Semi-Dwarf Cereal Mutants and Their Use in Cross-Breeding Ii

IAEA-TECDOC-307

SEMI-DWARF CEREAL MUTANTS AND THEIR USE IN CROSS-BREEDING II

PROCEEDINGS OF A RESEARCH CO-ORDINATION MEETING ON EVALUATION OF SEMI-DWARF CEREAL MUTANTS FOR CROSS BREEDING ORGANIZEE TH Y DB JOINT FAO/IAEA DIVISIO ISOTOPF NO RADIATIOD EAN N APPLICATIONS OF ATOMIC ENERGY FOR FOOD AND AGRICULTURAL DEVELOPMENT AND HELD IN DAVIS, CALIFORNIA, USA 30 AUGUST - 3 SEPTEMBER 1982

A TECHNICAL DOCUMENT ISSUED BY THE INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1984 SEMI-DWARF CEREAL MUTANTS AND THEIR USE IN CROSS-BREEDING II IAEA, VIENNA, 1984 IAEA-TECDOC-307

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It has become increasingly evident that the role of induced mutations in crop improvement extend r beyonfa s d their direct exploitatio w culne - s a n tivars n impressivA . e numbe f cultivaro r s already have been developed using induced mutant s gena s e donor r desirablfo s e traits e resultTh . s thus obtained imply an even greater potential of mutants as parents for recombination breeding.

The yield potential of cereal cultivars in particular, has been considerably increased through improved lodging resistance, whic s permitteha h d fuller exploitatio f wateo nd nutrienan r t inputs e mosTh .t important plant character associated with lodging resistanc s culi e m length. Mutation o reducet s d culm length (semi-dwarf height) are among the most common and easily identified amon e viablth g e genetic changes induce n cerealse othei d th rn O hand. , they have been rare in nature or have been selected against. Thus, only a few semidwarfing gene source e know ar sd use breedinn an i d f cerealss o likelgi t yYe . that onl a ysmal l portioe potentiath f o n l genetic variabilit r planfo y t height has yet been revealed for possible exploitation, even considering the mutant variation evaluate o datet d .

The use in breeding of only a small number of semi-dwarfing gene sources subjects these important food crops to risks of genetic vulnerability towards pest d diseasean s s associate y limitean df o wit widde e th ranghus e f genetio e c variation. It is also notable that certain defects were found to be associated wite semi-dwarfinth h g traits currently used, suc s incompleta h e panicle exsertion in rice and reduced coleoptile length in wheat.

In view of the potential risks of genetic vulnerability, and the fact that many induced semi-dwarf mutants havt eveno en been evaluate r theifo d r potential use in cross breeding, a Co-ordinated Research Programme on the Evaluation of Semi-Dwarf Mutants as Cross-Breeding Materials in Cereals was initiate n 198i d0 witobjective th h provido t e e cereal breeders with alternative source f gene o sr short-staturfo s e plant types e seconTh . d researc- co h ordination meeting of this programme was held August 30-September 3, 1982 at Davis, California. At the meeting, participants reviewed the status of genetic studies and the various aspects of breeding for semi-dwarf plant type in cereals, considered methods for evaluating and exploiting semi-dwarfing gene sources in cross- breeding programmes and made recommendations regarding future research.

The present publication includes the papers presented at the meeting, a summar f pointo y s discussed, list f semi-dwarfino s g stocks under investi- e gationconclusionth d an , d recommendationan s s reached. CONTENTS

Highly productive mutant genotypes in barley — Direct use in practice and in successive recombination ...... 7 A. Gustafsson, U. Lundqvist Cell sizceld elan numbe dwarn ri f mutant barlef so y (Hordeum vulgäre) ...... 9 1 . A.D. Blonstein, M.D. Gale Progres evaluatione th n s i breeding n i e us ,geneti d an , c analysi semi-dwarf so f mutants of barley ...... 31 S.E. Ullrich, CE. Muir Progress in the evaluation, use in breeding, and genetic analysis of semidwarf mutants of wheat ...... 9 3 . CF. Konzak, M.R. Wüson, P.A. Franks Production and evaluation of dwarf and semi-dwarf winter wheat mutants ...... 51 Z. Barabâs, Z. Kertész The effect of the Tom Thumb dwarfing gene on grain size and grain number in wheat (Triticumaestivum) ...... 63 M.D. Gale, J.E. Flintham Norie effece th dwarfinTh 0 f n1 o t g gene, Rht2, yield-biomasn o s relationship whean si t (Triticum aestivum) ...... 1 7 . . W/ . Snape, B.B. Parker Inheritance of culm height and grain yield in durum wheat ...... 79 FilevK. Yield performance of F3 progenies from a durum wheat cross involving two different semidwarfing genes: Rhtl and SD mutation ...... 91 Giorgi,B. Barbera,F. Bitti,O. CavicchioniG. Semi-dwarf mutant triticaln si whead ean t breeding ...... 1 10 . C.J. Driscott Genetic studie dwarn so f triticale mutants ...... l Il . NalepaS. Genetic and agronomic evaluation of induced semidwarf mutants of rice ...... 125 J.N. Rutger Evaluatio genetid nan c analysi semi-dwarf so f mutant ricn si e (Oryza sativa ) ...... L. 5 13 . M.A. Awan, A.A. Cheema, G.R. Tahir Agronomic characteristics of semi-dwarf mutant lines and gene analysis of semi- dwarfness in rice ...... 149 H. Yamagata, T. Tanisaka, Y. Okumoto, M. Nishimura Genetic evaluatio planf no t type variant desirablr sfo e physiological attribute theid san r use in the study of the physiological basis of yield in rice ...... 165 E.A. Siddiq, P.R. Ready Genetics of some induced and spontaneous dwarfs of rice and their utilization in cross-breeding ...... 197 E.A. Siddiq, A.R. Sadananda, V.P. Singh, F.W. Zaman semi-dwarf o The eus f mutant breedins sa g material ricn si e ...... 9 20 . P. Khambanonda, P. Pookamana, A. Sarigabutr Significance of semi-dwarf varieties of rice and their evolution through induced mutations ...... 9 21 . B. Bari, G. Mustafa, A.M. Soomro, A.W. Baloch Induced semi-dwarf mutants in upland rice ...... 225 A.M. Riyanti Sumanggono, IsmachinM. Kartoprawiro, P.S. Mugiono Characterization and evaluation of semi-dwarf mutants in Indica rice ...... 229 T.P. Ready, Vaidyanath,K. G.M. Ready Studie reducen so d height mutant ricn si e ...... 7 24 . P. Narahari, BhagwatG. S. A rapid seedüng test for gibberellin response in rice (abstract only) ...... 259 P. Narahari, BhagwatG. S. Effectivenes breedinf o s g short-stature rice cultivar mutatioy sb n inductio hybridiza. nvs - tion (Short communication) ...... 261 CM. Hu List semi-dwarf so f cereal stocks ...... 3 26 . Conclusion recommendationd san s ...... 1 28 . Lis participantf to observerd san s ...... 9 28 . HIGHLY PRODUCTIVE MUTANT GENOTYPE BARLEN SI Y- DIRECT USE IN PRACTICE AND IN SUCCESSIVE RECOMBINATION

A. GUSTAFSSON, U. LUNDQVIST Institute of Genetics, University of Lund and Svalöf AB, Svalöv, Sweden

Abstract

Three special cases of induced mutations in barley are discussed in this paper. They are denoted here as the Gunilla, the Pallas and the Mari cases, afte e threrth e named varietie whico t soriginae th h l mutants gave rise. The original mutants described represent just a small sample e induceth f o d mutants, man whicf yo h have been teste practicn i d d an e have been further studie basin i d c genetic d evolutionaran s y research. The three approved varieties have given rise to further recombination families, which also to some extent have been fused. mutane th f to caseo Tw Pallas- Mard san wer- i e directly usefun i l practic officialld an e y approved e thirTh . d case involve mutana d f o t special appearance - a "bushy type" with an intense blue wax coating and wit suprema h e lodging resistance mutane Th .s use developintn wa i d e th g Gunilla variety, which aros recombinatioy eb n breeding. This variets ha y been highly satisfactory in further gene recombination work. A similar situation has prevailed with regard to the Pallas and Mari families arising after gene recombination, too. Up to now, the Gunilla, Palla Mard san i families includ lona e g serie f releaseso officialld an d y approved varieties. Several of them represent valuable agricultural contributions with wide areas of cultivation. These three mutant wits- h their recombination o familiet d le s- greatly increased straw stiffnes higd san h grain production. Their phenotypic expression often corresponds to a dwarf or semidwarf descrip- mutante Mare th th f i o s- tiongenotyp e On . represent- e grousa f po gene d allelesan s which give ris profouno et d changee photoperioth n i s d (and partiall ythermoperiode th als n i o ) behaviour n factI . , often even such small changes have a fundamental influence on adaptation and distribution. Dat presentee aar d analysin properte th g lodginf yo g resistance with the backgroun plantf do , tille d internodran e structure methoA . f do partial back-mutation was worked out in separating traits generally muta- ting together methoe Th . Wettsteidn analysie vo adopte th . D r y nfo db s of erectoides mutations in barley was found to be appropriate in compli- cated case traif so t combinations.

Introduction analysin Ia n Swedisf so h Plant Breeding (Statens offentliga utred- ningar 1978:23 Björ. )Dr n Sigurbjörnsson (former employe PAO/IABf eo A Vienna beed )ha n invite discuso t d s induced mutatio tooa plann s li na t breeding. He remarked (p. 227) that "a considerable part of the world 'know how' in the area of mutation breeding is found in the Scandinavian countries t woulI . highle db y desirabl thesf i e e countries could unite in new efforts to improve this important technology against world starva- tiomakd bettet an ni e r know widn i n e circles" (translated from Swedish).

o exaggerationn Thi s i s . Different aspecte inductioth n so f o n mutations and their use in plant breeding had indeed been discussed at an early time. Fro scientifima c poin s fascinatin vief wa o tt wi watco t g h the successful creatio w variabilitne f o n cron i y p plant specie y irrasb - diation and chemical mutagenesis, not least in cereals and legumes. (See, for instance, the volume on "Mutation Research in Plants - Acta Agriculturae Scandinavica IV:38 1954). A brief resum e appropriatb her y ema e sinc mann i e y - circlein e th s duction of mutations in crop plants is still considered theoretical and vague in character, although in fact recent experiments have aimed at practical implication mosd an st certainly have given valuable results, both from theoretical and practical points of view, not least in species as barley, wheat, oats, ricd peasan e . Indee seriea d extractef so d mutants have obtained a wide distribution in cultivation. Even rapid progres A genDN ef o stechnique s doe r opinions ou not n i , , exclude future use of radiation and chemicals in mutagenesis. This is valid, too, for studiee spontaneouth f o s s mutation process. We plan to illustrate our presentation with a few induced mutants in barley, around which families of new variation have been established. They also demonstrat e induceeth d origi "semi-dwarf o n f charactersd "an their effects on adaptation and productivity, since this is the theme of the present meeting. In fact, much more data, not considered here, could have been included, dealin r examplfo g e with anthocyanin metabolisd an m disease resistance e prefew literaturt e refeo ,bu th t r o e rt th n i e field, published not least by IAEA in numerous, volumes.

The Gunnilla cas f lodgineo g resistance

This mutant gene (44/3; GUSTAFSSON 1947, 1975) was isolated in the late thirties after X-irradiation of seeds in Gull barley (Golden bar- deviatet leyI ). d strikingly from other strains studietime n th i e t a d the barley assortmen Swedise th f to h Seed Associatio Svalövt na e Th . seedlings became "bushy thein "i r early growt hculme th habi sd an devet - loped an intense blue wax coat. The spikes did not slope, as is the rule in Gull itself, but were more erect. In the mutant description, culm length was noted as less than in Gull barley. A most remarkable feature was indeed the outstanding straw strength (lodging resistance). The mutan brancs e testetwa th t ha d station Seee th d f Associationso , among them especially at the Vasternorrland station (circa 63°N) under its leader Dr. K. Viklund. At a board meeting of the Association (1971, p. 396) emphasizee ,h unique dth e propertie thif so s followe straith n i n- ing enthusiasti y (translatecwa d from Swedish): gueste "Somth f eso today may perhaps remember a visit to our branch station a really rainy summer day in 1945. In a short time 45 mm of rain poured down, and our cereal trials lodged entirely, felled to the ground, but four islands of one and the same strain remained erect. It is really somewhat of world history(I this n )variete i Th . stiflodga t y no s thafed wa strikingtdi - ly waxy mutant from Gull barley. It was perhaps the first time, this 26th of July 1945, that a clear proof was obtained concerning the immedi- ate practical function of mutâtional research**. "This blue-dewy mutant

8 from Gul s soolwa n incorporate recombinatioe th n i d n r systeou f mo station (Opa Veglx Majx a a derivatives)" evidenn A . w t ne resula s twa cross variety, give e codth ne numbe6410* A f 8- straw-stiffro , high yielding, erect, "short to medium tall" - which in 1970 was approved as an original variety, with plant breeders' right, under the name of "Gunilla barley". In a few years the variety became widespread and a well sold variety from Svalöf, still with a rather wide area of cultivation. After this success, Wiklund applied recombination techniques in orde o includt r e also other prominent varietie mutantd an s s inte th o North-Swedish barley programme. A description of results and their in- terpretatio n articlfouns a i n n i dGustafssoy b e . (1971)al t e_ n. Recom- binants were selected from the northern variety Birgitta, after crossing witmutane th h t mat-a** (Mari f Bonus)o , givin high-yieldge th ris o t e - ing early d Salvstrainan ea barleysEv s , later approve originas a d l varieties. The cross of the Norwegian variety Domen and the mutant Mari (see below) gave rise to the high-yielding and stiff-straw variety Kristina, which has supreme brewery properties. Kristina - as well as the other mutant cross derivatives mentione stils i d- l include recombinae th n i d - tion families. Another result obtaine Wiklund'n i d s recombination work came from the inter-crossing of the Gunilla and Mari varieties, combining their mutant genes. This led 1969n prominene i ,th ,o t t high-yielding variety "Pernilla", of semi-dwarf appearance: "with short medium long culms", also officially approved with plant breeders' rights (Wiberg 1982). Mare Th i genr earlinessfo e . lodging resistanc d photoperioan e d

insensitivity e MarTh i gene (mat-a. s isolate)wa 8 195n i ddirectld 0an y gave rise to a new original variety (Mari = matura and ri^gidus) which was approved i nvariet w 1960ne e wit.- yshorTh s it h t stra wimmediatel- y gaine- ex d ceptional interest owing to its markedly increased earliness compared with other cultivated two-row varieties, and its considerable straw strength mutane Th ."short-das i t y tolerant" (i.e., photoperiod insensitive). It produces a considerable amount of seed under extremely short- day (8-12 hours of light) (Gustafsson et al. 1982). The mutation is allelic witmutatioe th h n "erectoides 16", from Maja barley, combininn a g increas earlinessn i e , straw strengt higd an hh 1000-grain weight wite th h photoperiod insensitivity mentioned Maje Th a. mutan originalls twa y considered an erectoides mutant with rather dense ert-o16 ears, like the erectoides types of other gene loci. Erectoides 16 is indeed a semi- dwarf mutant in its characters. The Mari mutant (from Bonus), with a series of recombinants, has obtained a wide distribution and has been tested in several continents. The previously mentioned cross products comprise the varieties Eva and Salve, as well as Pernilla. In addition, the more southern Mona variet Hagberg). (A ymentionee b y ,ma backa ( d - cross variety involving mildew-resistant Monte Christo genes), as well as Kristina (a Domen Product). Both Mona and Kristina have the Mari gene incorporated in the breeding programme. Norwegian "Stange" and "Solid" barleys arose from the cross Ingrid x Mari (S. Frogner). The mutant Mari s includewa Finnisn i d h recombination work alss (Eeroha o d bee)an n a n ingredient in CIMMYT experiments (Gustafsson et al. 1982). In Swedish mutation work, more than 800 praematurum (early) mutants have been isolated wit higa h h numbe genf ro e locallelesd an i . Earli- nes barlen i s y cover "oligopolygenicn a s " system with mutations ranging from extreme to slight alterations of earliness. This is governed by difference e patterth n i sf physiologica no morphologicad an l l changes, where both profound and slight photoperiod reactions play an important rol adaptationn i e . Certain gene loci have been define r theifo d r distinct influenc n earlinesseo . Most characteristi matura-e th s i c a locus with the Mari mutant (mat-a8. also denoted ea* by Japanese scientists). Almost all praematurum types, compared with ordinary varieties, possess more or less shortened culms, and are, in fact, dwarfs or semi- dwarfs in classification.

The Pallas gene for lodging resistance and high-yielding ability

e so-calleTh d Pallas variet s firsywa t described internationallt a y the United Nations Conferenc Peacefue th n eo l Use Atomif so c Energy (Borg 1955). emutantal e Th . t gene (ert-k 3erectoide= 2 givin) s32 g riso et Pallas barley s isolate,wa 194n i segregatinda n 7i generatio2 gM n after X-ray irradiation of Bonas seeds in 1946. Pallas barley was approved as an original variety in 1955. Apart from its use in Sweden, Pallas became cultivated in Denmark, Great Britain and Ireland, as well Spainn ai smutane Th .s soo twa n incorporate seriea n i dvarietaf so l crosses furthewa d an sr improve geny db e recombinatio sucn i n h crossing (I. Wahlstedt and A. Hagberg). In this way, a series of new cultivars were introduce markete th n r instancedo , fo , Hellas, Visir, Senat, Rupal. In Canada, the recombination of Pallas with native material gave variete th ris o t ey Atlanta.

Concernin value th gcultivatiof eo Pallaf no s barley tako ,t e just one example Generae ,th l Seed Compan Swedef yo n (whic longeo hn r exists n aindependena s t organization para Svalöf s to i annuall) t f,AB bu y pub- lishe economin a d c survey coverin followine gth g details with regaro t d the Pallas situation (1978, p. 6): "Spain is a very large and imposing agricultural country barlee Th . y cultivation alone comprises three million hectares. The Svalöf varieties Pallas and Hellas have previously covere acreagn da circf eo 0 percent.a4 " This would mea Pallar nfo d san Hellas a very huge acreage for a sequence of years. Even in 1981 and 1982, after more tha year0 n2 existencef so , Palla Hellad san s maintainn a large area of cultivation (Wiklund 1982). Unfortunately, these varieties wer bret milder eno fo d w resistance. However, after gene recombination, several varieties with disease resistance were released (Visir, Sena Rupal)d tan . Recently mildew ,ne w resistance mutants have been introduced in some prominent varieties: Bonus, Pallas, Mari, Foma, Kristin varioud aan s type specificitf so degred yan e f resistanco e have been isolate testedd dan n spitI . f interestineo g result resistancef so beer fa ,n nono abls thef competeo o s et mha n eo markee th t witrecombinante hth s involving primitive source resistf so - ance. Bonus and Pallas show some differences in photo- and thermo-period reaction (Gustafsso 1977. al 258). t ,np e instancer ,fo , with regaro dt time of heading and the generative/vegetative efficiency (Gustafsson and Ekman 1967) average Th . e differenc stran i e w height betweeo tw e nth cultivars in Danish cultivation was for five years 2.4 cm. Pallas was definitely shorter than Bonus. The same holds true for numerous other erectoids compared with their respective parents. Many such types are of a distinct semi-dwarf charac- . Thiter s stand relatio n length e si intere numbee th th th d f o -srno an t nodes (cf. Ehrenberg et al. 1956). Bonus has five, six and seven inter- maie nodeth n n plancula so f percentmo 2 t d (11an ,7 ,8 respectively).

10 In comparable cultures, Pallas had five and six internodes (55 and 45 percent, respectively) articln a n I f 1954.eo , Wettstein analysed such character detailn i s , includin gr densitie ea dat n ao d crosan s s section areas from various erectoides of the parent strains Bonus and Gull alse H (Figo. studie1) . correlatioe th d n betwee degree th n f straeo w bending by weight and the cross section areas, especially of the apical internodes I and II. In a previous summary paper, results relating to internode number and lengths in early as well as erectoid mutants in barley were presented (Indian Journa Geneticf lo Pland an s t Breeding. pp ; 2 . , VolNo , .17 276-295) (Fig . Bonu 2) .suitabla s- e experimental materia hadl- , under normal field conditions, as indicated above, primarily plants with six internodes per main culm, less with five internodes per main culm and just a few with seven internodes. In mutant early 2 - which is a high- yielding mutant from Bonus with an increased loding resistance - all

plants examined had just five internodes per main culm. In Mari (ma_t-a 8 = early 8), 63% of the plants had five internodes per main culm and the remaining 37% six internodes. No early mutant studied had more thainternodesx si n A "gian. t mutation" contrarye th n ,o , also examined, developed longer straw with high numbers of internodes: 10% percent had 5 internode leadinr pe sd seveinternodex ha si g n% d 7 straw ha d % an s ,83 internodes. Straw lenght and grain yield increased parallel with the number of internodes Bonun ,i mutants sit itseln i s s a f(Ehrenber t al.ge . 1956 19). p , . Lodging resistance, yiel d adaptabilitan d erectoidef o y s mutants It was evident at an early stage of the mutation work in barley that the so-called erectoides mutants generally possess a high lodging resistance and that this behaviour is related to changes in straw structure, comprising culm lengths, number of internodes and tillering ability. Other characters also influence lodging resistance r instance,fo , cross sectio nculmse areath f ,so bundle diameter bendind an s g abilitiey b s weight (Wettstein, 1954). comparisoe Th primitivf no derived an e d wheat varietie corresd san - ponding barley types showed definite difference morphologican i s d lan anatomical structures (Fig. 3); for instance, Dala wheat, primitive and lodging, compared with Pondus wheat, derived and straw-stiff; on the other hand, Bonus barley: a lodging cross variety, compared with the erectoide whic, s14 mutanthd an lodg 3 s2 e less. These charactere sar directly related to differences in straw structure. Characteristic for lodging resistant varieties are long apical internodes (I and II) and short or missing basal internodes (IV and V). In wheat crose ,th s section area basaf so l internode smalle sar ; thee ar y definitely larger in barley. In fact, a modernization of both wheat and barley would be possible utilizing the experience gained from mutant erectoids, i.e., semi-dwarf morphology and anatomy. Wettstein (1954 alse ;se o Gustafsso Wettsteid nan n 1958) succeeded in inducing mutation and back-mutation in the ear density of erectoides mutants, improving both their adaptabilit lodgind an y g resistancen I . the preceding pages serie,a mutationaf so l change straf so w morphology

11 and anatomy have been discussed doubto N . , mutation experiments will provide further informatio n increaseo n d yiel d graian d n qualitn i y cereal specie method n welo s a ss la agriculturaf so l managemen f fertio t - lizers.

Aspects of mutagenesis Mutation analysis in barley indicates that the mutation process is t fullno randoa y m proces possibls i d tha an t si t govero t e n mutan- in t duction in some aspects already by radiations and mutagenic chemicals. Of the erectoid cases, for instance, the rather commmon ert-a and ert-c mutants arise after quite different kind mutagenif o s c treatments: ert-a mutants easily arise after chemical treatments (with epoxides, epimines, organic sulfonates ) verr concomitanw o wit fe yo n h t chromosome breaks; ert-c., on the other hand, arises more readily using irradiation, with consequen paraller o t l chromosome breakage (Gustafsson 1963; Perssod an n Hagberg 1969) e contrasTh . strikings i t . So far, no translocations having a chromosome break close to or at the site of the ert-c mutation, were found using chemical mutagens. This contrasts to the abundant cases of chromosome translocations appearing after irradiatio nX-raysr o wit- ft h , proton neutronsd an s . Reciprocal translocations involv o balancetw e d chromosomm genet eno break-o d d san rally harm the organism. Rather to the contrary: homozygous reciprocal translocations involving the ert-c. locus are highly productive (Gustafsson 1963). It may be emphasized here that among the mutations which inhibit wax formatio n spikesno , leaf sheath lear so f blades, distinct specificities have been found (U, Lundqvist), leading to an excess - or a deficit - of mutation e specifith n i s c gene loci, dependin e typ mutagenith f eo n o g c agent: radiatio chemicalr no slocue (FigTh s . .eer-i5) r instance.fo , gives ris numerouo t e s mutations with X-ray neutronsd an s almost ,bu t none with chemicals (ethylene imine or ethylmethane sulfonate). On the contrary, cer-j gives no mutants with neutrons, a few with X-rays and numerous ones with chemical mutagens. Apparently, neutron chemicad an s l mutagens represent opposite extremes as agents for the induction of mutation specifit sa c gene loci. Also highly interesting, and studied by U. Lundqvist and P. von Wettstein-Knowles, is the extreme specificity of the complex eceriferum locus comprising the three "sites" c_, £ and u ("a cluster gene"). Triplex and duplex locus changes readily appear with neutrons, are rare X-rayd an ethyl-methand wit- san h e sulfonat missine ar d gean after treatment with other sulfonates and ethylene imine. In his studies of erectoides mutants, Wettstein (1954) applied the back-mutation technique using radiation (Fig. 4). This approach is generally neglected presumablt ,bu y lead importano st t half-way reversionf so spike and stem characters, separate or together, as already stressed in papee th r cited. Finally evidens i t ,i t thadominance tth e relation manf so y genes vary with the genetic or environmental millieu. A series of heterozygous gradation erectoif so d characters were found ranging from super-dominance and dominance to semi-dominance, semi-recessivity and recessivity (cf. Ehrenberg et al.. 1956).

12 It may also be pointed out that among the numerous known eceriferum loci, there are some in which the mutated allele (alleles) is fully domi- nan expressionn i t n locuI . s Cer-y 7 neutron-induce1 y d allelic mutations of dominant character have appeared (U. Lundqvist). In loci Cer-n and Cer- w caseqfe f strictlo a sther e ar e y dominant mutation mutan. g e tTh . in this cas s induceewa y sodiub d m azide. Spontaneous dominant casef so "glossy ear" (eceriferum) have been discussed recentl Gymey yb r (1981). Distinct cultivars witcharactee th h r mentioned occu varioun i r s European spring barley assortments (Feronia, Dragon, Gula, Rapid, Rosie). Up to w theino r allelis d genman e locatiobeet no n s determinedha n .

REFERENCES

BORG, H., FRÖIER, K. and GUSTAFSSON, X. , 1955, Pallas barley, a variety produced by ionizing radiation: its significance for plant breeding and evolution. Proc. Second United Nations Conf. Peaceful Uses of Atomic Energy Z7 (1958): 341-349.

EHRENBERG GUSTAFSSON, ,L. WETTSTEINd an 1956. n ,A vo . . ,D Studien so the mutation process in plants - regularities and intentional control. Conf Chrom.n .o , Wageningen: Lecture 5:1-29. ZWOLLE, The Netherlands FROGNER 1977. ,S . "Stange ollriky N "- , toradet bygsor östlandetr tfo . Norsk Landbruk nr 5/18.

GUSTAFSSON . 1947,£ . Mutation agriculturan i s l plants. Heredita: 33 s 1-100. GUSTAFSSON 1963. ,A . Productive mutations induce barlen i d y ionizinyb g radiation chemicad an s l mutagens. Hereditas 50:211-263.

GUSTAFSSON, A*. 1975. Mutations in plant breeding - a glance back and looa k forward : Proc In Int.h .5t . Congr. Rad. Res., Seattle (1974). Académie Press, Inc.:81-85.

GUSTAFSSON, i., DORMLING, I. and LUNDQVIST, U. 1982. Gene, genotype and barley climatology. Biol. Zbl. 101:763-782. GUSTAFSSON, A. and EKMAN, G. 1967. Yield efficiency of the X-ray mutant Svalof's 'Pallas barley'. Der Züchter 37:42-46.

GUSTAFSSON, JL , EKMAN, G. and DORMLING, I. 1977. Effects Pallae th f so gen barleyn i e : phene analysis, over-dominance, variability. Hereditas 86:251-266.

GUSTAFSSON, A., HAGBERG, A. , PERSSON, G., and WIKLUND, K. 1971. Induced mutations and barley improvement. Theor. Appl. Gen. 41:239-248. GUSTAFSSON, A. und WETTSTEIN, D. von 1958. Mutationen und Mutations- züchtung : HandbucIn . Pflanzenzüchtun. hd Pare. gI y Berli. nu Hamburg. 2. Auflage: 612-690. GYMER, P.T. 1981. Glossy-eared cultivars. Barley Genetics Newsletter 11:19.

13 HAGBERG GUSTAFSSONNYBOMd , ,an A. . ,N , 1952,L . Allelisfff o l erecboides mutation barleyn i s . Hereditas 38:510-512.

LUNDQV1ST . 1975,U . Locus distributio f induceo n d eceriferum mutants in barley. Barley Genetics III: 162-163.

PERSSON, G. and HAGBERG, A. 1969. Induced variation in a quantitative characte barleyn i r . Morpholog cytogeneticd an y f erectoideso s mutants. Heredits 61:115-178.

WETTSTEIN. D. von 1954. The pleiotropic effects of erectoides factors d theian r bearinproperte th n o gf stra yo w stiffness. Acta Agric. Scand. IV. 3:491-506.

WETTSTEIN von. ,D , GUSTAFSSON EHRENBERGd un . ,A 1957. ,L . Mutations- forschung und Züchtung. Arbeitsgemeinschaft für Forschung des Landes Nordrhein-Westfalen, Heft 73:7-60. WIBERG, A. 1982. Pernilia körn - en ny utmanare fran Svalöf (Pernilia Barley - A new challenging barley strain from Svalöv) - Aktuellt fran Svalof 1:34-40. WIKLUND 1971. ,K . Norrländsk växtförädling (Plant Breedin Northern i g n Sweden). Sveriges Utsädesför. Tidskr. 81:395-413.

WIKLUND, K. 1982. Ett Svalöfs utlandsprojekt - Spanien. (A Svalöf project abroa Spain)- d . Aktuellt fran Svalöf 1:28-33.

flm car- density 7. interned« I internedT BJ « u.n4«h length 30 «0 28 38 -

26 36 2« 34 22 39 1 20 30

212*23 Eta « 21 £ 6 «* Crosaection -area bundle -diameter int.I n1 i.

46 H- 19 42

0212t X S « 6

Fig .1 Variatio allelef ert-locue no quantitativo t th s t a sa , sa e effect differenn so t phenotypic characters Bonus» + (B ., G+ - Gull, 28, 21, 23, 19, 6, 11 » erectoides mutants of Bonu Gulld san , -rj- double mutant ert-c1^11) (WETTSTEIN 1954; densitr Dateea f so y after HAGBERG, NYBOd Man GUSTAFSSON 1952). 14 Bonus 4U-

~" -] -, p 20- k -l ^ "U 0- iimFT iimsisi niismra 11% 87% 2%

Earl ya Early4

- - - 20 Iri IK II1IT II1KÏÏI 100% 100%

Early 8 40

20- 7^ k iijiiio i i IIY B ' ' 63% 27%

40- VJIdIII 1 -- 20- ^ m, k 10% 83% 7%

2 Fig. Relative internode numbe lengtd an r Bonuf o h s barle foud an yr Bonus mutants. The percentages beneath the diagrams denote the proportion of leading culms with 5, 6 or 7 internodes, respectively.

15 70 —

60 - h 50 - 0<

40 -

30 -

20 - 10 - 111 hllLIflfn nn l D1 P3 2 BB 2 3P 1D 4 t D P B 23 14 D P B 23 14 B 23 14 n III IV V

Fig .3 Above: Numbe lengtd ran f internodeho mair spe n culm: Dala wheat (D) compared with the more lodging resistant Pondus wheat (P), and Bonus barley (B) commpared with erectoides . 14 mutant d an 3 s2 Below: Culm cross section areas of Dala and Pondus wheats, compared with culm cross sections areas of Bonus barley and its lodging resistant erectoides mutant 23. (After GUSTAFSSO WETTSTEId Nan N 1958).

16 0______i m 6 3 4 3 2 3 0 3 8 2 6 2 4 2 2 2 Ährcndicht 0 2 8 1 c tu

10 II —

f 3 ï : i, ii B>, 1: ti, i1 R, £: R,» i R , [. , B R, E R, S' IV c 'c d 11 c d 111, i d £ 1 dVd 1

Fig. 4 Back-mutation techniques applied to split composite mutant characters thin ;i s case with regar fulo t dhalf-war lo y reversion f spiks o d steean m traits. d an 3 2 t Er reversion= ; 2 2 R (d Bonusd = B an an 1 s^ ;R E = erectoides 23). above: spike density below: internod etotaf o lengt % l n culi h m length

17 PERCEN MUTANTR CE F TO EACT SA H LOCUS C NORMALIZE R MUTAGENDFO S)

cuq izaazjntzej pgbe

SULFONATES

40 - 40

20 - 20 III III,,II,M ETH V LEIME- (MINE

40 40 20 lll.lll.llll.il 20 NEUTRONS

60 60

40 40

2O 20 111 J Li» X-RAYS

40 40 20 iilliLilLÉ 20 e u q i zj n t a« i p 9 »>

Fig. 5 Specificities of mutation frequencies of eceriferum genes are found after the application of different mutagenic agents (LUNDQVIST 1975). Compare for instance the mutation rates of genes i., j. and £.

18 CELL SIZE AND CELL NUMBER IN DWARF MUTANTS OF BARLEY (Hordeum vulgäre)

A.D. BLONSTEIN, M.D. GALE Plant Breeding Institute, Cambridge, United Kingdom

Abstract Sixteen height mutants, induce y sodiub d m azide treatmene th f o t two-rowed barley variety Proctor, have been use o investigatt d e th e relationship between the extent and nature of stem shortening with alteration n celi s l sizd celan e l numbere pleioth d -,an tropic effects of dwarfing genes on vegetative development and agronomic performance e studieTh . n epidermaso l cell number and cell e lengtdevelopmentallth n i h y earlies d latestan t elongated vegetative tissues - the coleoptile and peduncle respectivel - suggesy t that celprimare lth e numbeb y y deterrma - minant of plant height. One semi-prosträte and one erectoides mutant are used to illustrate different cell number/cell size strategie d theian s r relationships with gibberellin sensitivity, growth rat d lodginean g resistanc discussede ear .

1. INTRODUCTION e smal th s witA l al hgrai n cereals, barley breedere sar continually seeking sources of improved lodging resistance which will allow their crop to exploit the higher nitrogen inputs used in agriculture today. Progress in identifying suitable genetic source f stifso f stra bees wha n slowe r barlerfo y than ricd ean wheat and may be reflected, in Britain, in barley's relatively smaller average yield increases over the last few decades {!}. This paper reports part of a project in which an attempt has been made to examine how changes in cell number and/or cell size» are associated with altered plant height. Previous work with wheat varieties has indicated that shorter internodes {2} and coleoptile associatee ar } {3 s d wit reductioa h celn i n l number. The pleiotropic effects of height genes on developmental physiology and agronomic performance have also been studied to examine how these might relate to changes in cellular architecture. The dwarfs investigated fall into several categories thesf o o semi-prostrate- Tw . erectoidesd ean e ar - the phenotypes which have been most extensively exploiten i d commercial barley production e examplon d f eac,an eo uses i ho t d illustrat detain i e varioue th l s effect f theiso r different dwarfing genes.

19 . 2 GENOTYPE METHODD SAN S 2.1. Mutagenesis and mutant selection Mutants were induced in the spring barley variety Proctor using the sodium azide technique described by Kleinhofs et aZ.{4} From among 1500 M2 families sixteen mutants were finally selected.

The genotypes included one extreme dwarfs several semi- prostrate, erecto-Ldes nutansd an semi-dwarf e linon e d whican s h s tallewa r than Proctor. Tests of all el ism between the mutants have shown that the majority carry single independent genes, which give e th ris o t e differences in height from Proctor. Although conclusive evidence has not been obtained, it is probable, however, that the two semi-prostrates carry all el es at the same locus. 2.2. Growth conditions e resultMosth f to s were obtained from plants grown i n controlled environment cabinets. Similar cabinets were used in a serie f experimento s t conditionsa lighth 6 1 ,f o sfluorescen t supplemented by incandescent 675 yE cm"2 s~V 8 h dark, 15°C/10°C at 85% r.h. in 8 cm pots with automatic capillary irrigation. e lodginTh g scores were obtaine fiela n i dd experimenn ti which each genotype was replicated 16 times and each plot consisted of ten 1.16 m rows with plants at 5 cm spacing within, and 10 cm spacing between, rows. 2.3. Cell length and cell number measurements 2.3.1. Peduncle. Using plants grow controllen i n d environments, impressions wer stee th madm f surfaco e e usin saturatea g d solutiof o n polystyrene dissolved in 1:1 chloroform:toluene. Measurements wer e0 epiderma mad5 f eo l cells similan ,i r positions relative to stomatal files, in sections along the stem.

2.3.2. Coleoptile Coleoptiles were grown at 18°C in constant light for 5 days using a technique described by Myhill and Konzac {5}. DNA measurements were made of entire coleoptiles by extraction into 5% perchloric acid {6} and quantitative estimation made using a diphenylamine method modified from Giles and Myers {7}. Direct measurements unde microscope rth e were also madn eo cells matur f frocentre o th m m ee5 coleoptiles whic beed ha hn incubated overnight in 6% NaOH. Outer epidermis and parenchyma cells were measured separately.

20 4 Coleoptil2. e growth respons gibberellio t e c acid. Mature coleoptile lengths were measure n seedlingo d s grown in distilled water and in a 1 x lO'^M GA3 solution using the Myhil d Konzaan l c t 18°methoa constann C} i {5 d t light3 .GA response is expressed as percentage increase over control.

3. RESULTS 3.1. Cell numbe d celran le peduncl th siz n i e e Initial observations of the epidermal cells in the upper- most stem internode in several genotypes showed that cell length increased linearly from the collar to the node beneath. Therefore mean cell lengt s calculatewa h d fromid-poine th m f to a regression»as typicaa show r fo n l Proctor peduncln i e Figure 1. In addition cell numbers were estimated as the number of cells in a single file from top to bottom of the peduncle (peduncle length/mean cell length).

500 PROCTOR

400

Mean cell length. 206 Cell number , 822

300

Collar 10 Position tkmg peduncle (cm)

Figure 1. Changes in cell length along a peduncle of Proctor.

21 3.].1 genotypel Al . s The cell number estimates from the peduncle are very highly correlated with final plant height (Figure 2) while cell lengths show-no such relationship (r(1= .001 ) > .05) 6df p , . Thut i s appears that the primary effect of all the mutant height n celo s li numbers ale l le . This more resulth e s i tremarkable unexpectedd ,an , because the peduncle does not constitute the same proportion of total stem length in all the genotypes. Although peduncle length is correlated with plant height (r(1= .744 ) 6< .001)df , p , some genotypes have relatively long and others, notably the ereotoides mutants, relatively short peduncles when expressed percentaga s a f finaeo l plant height woule On .d expect, therefore, that these differences in relative length might be associated with differences in cell length and this is confirmed strone bth y g positive correlation (r(16 df)=.746 < .001 ,p ) between epidermal cell length and the proportion that the peduncle contribute o planst t height.

801 Proctor

70.

E èè 60.

40J rUôdfK 9J2(p<. 001>

30-

20. 300 400 500 600 700 800 900 Peduncle epidermal cell number LSD(5%)-80 Figure 2. The association between estimated peduncle cell number (along a single file) and final plant height for Proctor and sixteen height mutants growcontrollea n i n d environment.

Note e resultexperimento Th .tw f so s have been combine Proctod an d r is shown twice on the graph. Each point represents the mean of three replicates.

22 3.1.2. Semi-prostrate and erectoides semi-dwarfs Two of the mutants are semi-prostrate, having a more spreading juvenile habit than Proctor, and producing more tillers. The ear is lax, and as long as, or longer than Proctor's previoua n I . s stud Wettsteiyn vo Haah d } an r {8 n found four independently derived semi-prostrate types to be allelic, and the two Proctor mutants probably carry alleles at the same locus, whic elsewhers ha h e been calle w {9}sd d . o mutantstw e th ,f O 1282 uses i , d , referreherSP o s t ea o t d illustrate this phenotype. By contrast, ther mane ear y loc whict a i h mutationn ca s giv ereotoidese th ris o t e (ert) barley type {10}. Erecto-Cdes barley e characterisesar a reduce y b d d spike internode length, r dens makinbroadea d ean e th g. Thefrequentle yar y shorter than the parent and in many instances (though not all) this phenotype displays modified vegetative characters, especially thick upright stems, and acutely held leaves. Mutant 545 (ER) n examplia s f suce o er&oto-idesn a h form. It is possible that the semi-dwarfing mutant alleles in SP and ER, which segregate as single recessive genes in backcrosses with Proctor e associate,ar d with other simultaneously induced background mutations. However, the characteristics discussed below are typical of all the mutant lines in each group, indicating that thee almosyar t certainly pleiotropic effecte semi-dwarfinth f so g s themselvesale l le .

Tabl . I Phenotypee f Proctoso exampled ran semi-prosträtf o s erecd ean t dwarf mutants. Tall Semi-dwarf Semi-prosträte Erect s.e.d. Proctor SP ER Height (cm) 77.4 50.7 57.2 2.29 1 7. 5 .7 10.Tille . 8 4rno 7. Peduncle 21.7 23.0 15.2 .90 (% total stem length) Ear length (cm) 8.32 9.23 6.36 .270 Ear density (cm) .50 .51 .38 .01 Aw 0 n emergence15. 5 13.3 1.59 (days after Proctor)

Note characterl Al . s were score plantn o d s grow controllen i n d environment cabinets densitr mea e r internodEa th .nea s e lengti y on ef h o measured over ten internodes on one side of the ear from the fifth floret,

23 Five morphological character e summarisear s r Proctorfo d , SP and ER in Table I. While both semi-dwarfing genes reduce height, they are associated with different tiller numbers, stem architecture and ear morphology, indicating that they have quite different pleiotropic effect n planso t characters other than height. Over all genotypes studied the mean proportion or total stem length accounted for by the peduncle is 23.2 per cent. SP lies close to the mean while ER has a relatively short peduncle. Tabl showI I e s clearly that this differenc accompanies ei a y b d similar difference in cell size, with the epidermal cells in ER being just over half the length of those in SP. The smaller differences in cell number are related directly to the difference in final plant height between the mutants (Figure 2).

Tabl I I e Epidermal cell number d lengthsan pedunclen i s s of Proctor and semi-dwarf mutants SP and ER. Peduncle Mean cell Cell number length (cm) (length(ym)) (One complete file) Proctor 16.9 205.9 822 SP 11.6 3 56 206.9 ER 8.8 127.6 694 7 .6 14.8 LS% 5 D 7 87.2

3.2. Cell number and cell length in coleoptiles While the peduncle is the last vegetative tissue to elongate, the coleoptile is the first. Therefore, to span the stage f vegetativso e plant development coleoptile ,th s ewa chose r furthenfo r studie celn so l siz celd ean l number. Cell numbe s estimater wa wayso tw n .i d Relativ conA eDN - tents of the fully expanded coleoptile were used to provide a cell number ranking between the genotypes. However, this method, which is fast and relatively simple to carry out, necessarily assumes that there are no differences in the degree of endopoly- ploidy in this tissue among the genotypes. Therefore direct cell size measurements were also mad coleoptiln eo e epidermal and parenchyma cell partian si l digeste tissueth f so . Only the results for the epidermis are discussed below. An estimate f celo l numbee fil on f epiderma eo n ri l coleoptile cellth n i s e was obtained as coleoptile length/mean epidermal cell length. The DNA and the direct cell measurements gave similar results becaust ,bu e fewer genotypes were studied usine th g former technique only the macerations will be dealt with here.

24 The relationships that were found with the peduncle were also found to be generally true for the coleoptile. Thus, ther a correlatio s ei f coleoptilno e length with plant height coleoptilf o < .05 d p = .516(r(1 )an < ) df 51 ,e.0 epidermal cell number with plant height (r(15 df) = .572, .01 < p < .05), but no correlation between epidermal cell length and plant height (r(1= .244 .05)) > 5df ,p . R E d 3.2.2an P S . Although coleoptile length is generally positively related to plant height, SP has a relatively long coleoptile (23.3 mm for a plant height of 50.7 cm) while that of ER is relatively short (18.7 mm for a height of 57.2 cm). As with the peduncle, these differences are strongly associated with differences in cell length (Table III) while the differences in ultimate plant height between the two mutants relate most closely to e differenceth celn i s l number estimates, whether these ar e obtaine y direcb d t observatio e derivear r o n d froA DN m measurements.

Table III. Coleoptile length, and cell number and cell length estimates in Proctor and examples of semi-prostrate and erect dwarf mutants.

Coleoptile Epidermal Epidermal Relative length cell length cell cell (mm) (um) Proctor 20.7 380 54.4 1 SP 23.3 460 50.8 .83

ER 18.7 356 52.4 1.02

s.e.d. 0.78 16.38 2.12 .074

from digests from DNA measurements

Coleoptile growth has been shown to be associated with its respons o variout e s phytohormones respons{11}GA n I . e tests, both SP and Proctor showed 3 similar responses .over their control lengths of 24.0 and 21.5% respectively, while ER gave a much reduced respons f 11.6eo % (sed 2.14%)= , indicating thae tth shorter reflecR cellE f o s ta lowere d potentia r expansiofo l n rather than unexpressed potential due to the absence of endogenous gibberellin.

25 3.3. Plant height durin. g ER developmen d an P S n i t The fact that the percentage of stem length accounted for e pedunclebth y P (relativelS f o s y R (relativelhighE d an ) y low) differ, implies tha e reversth t e relationships muse b t true for some of the other lower internodes. Indeed, an analysis f growto h rate thesn i so genotype tw e s shows that they attain their semi-dwarf stature by quite different developmental routes (Figure 3).

80 HEIGH d LEAan TF APPEARANCE DURING DEVELOPMENT ————— 78cm

57 cm

50cm

l! * E

20 C 60 80 Maturity Days

Figure 3. Rates of leaf appearance and changes in height of Proctor and examples of semi-prostrate (1282) and erect (545) dwarf mutants grown in a controlled environment.

Note. Points on curves represent the appearance of successive leaves witlargee th h r symbols indicating leaved an 7 s . Heigh10 t measurements wer leae th madf o ligulet e s as they appeared, with the stems held normal to the ground, and at maturity, to the base of the ear.

26 Over the first period of growth (during the appearance of the first five leaves), ER increases in height only slowly while SP has a growth rate indistinguishable from Proctor. Afte rP slowS lea , 5 sf dramaticall d finallan y y accelerates during the extension of the last internodes, while ER displays an accelerated increase in height during the emergence of leaves 7 to 10 but slows again at the end of vegetative growth. The relative lengths of the SP and ER peduncles therefore reflec rate tth f extensioe o tissuee th f no , implyings i s ,a reasonabl d confirme ean e relationshipth y b d s discussed above, that cell lengt mainls 1 h functioa y f degreo n f internodeo - ex e tension. Similarly at the very early stages of plant growth during which the coleoptile extends, ER (with a relatively short coleoptile) is growing very slowly relative to SP and Proctor. A prediction from these results would be, therefore, that in the early stages of stem extension the stem internode woulR E f do s have shor twoulP S cell d d an shav e cells similaf o r lengt Proctoro t h . . 3.4. Lodging under field conditions. In a field trial with plants closely spaced in small plots lodging scores were obtained for all genotypes. In general plant heigh directls i t y relate genotype'a o t d s propensito t y lodg < .05) p e < = .577.(r(1 1 ) Howeve,.0 df 6 r botsemie th h - prostrate mutants were worse than expected from this relation- e erectoidesth l al shid an pmutant s wer e moseth t lodging- resistant. Table IV demonstrates clearly that SP, which was considerably shorter than ER in the field, lodges almost as badly as Proctor, while ER is acceptably stiff strawed.

Table IV. Mean height and lodging scores for Proctor and examples of semi-prostrate and erect mutants. Tall Semi-dwarf R E s.e.d. P S Proctor Height (cm) 83.8 56.1 70.3 .8 1 Lodging score 4.5 4.3 1.1 .54

Note. Lodging scores, 0 = none, 9 = complete.

possibls Ii t e that stem strengt functioa s i h f cellulano r architecture. If this is so, it is clear that cell number is not the component involved in the difference between the semi- prostrat d thean eerectoide thae b sty mutantscelma t li d ,an e plansizth n tei tissues that collapse during lodginn a s i g important factor.

27 4. CONCLUSIONS 1. Amon a samplg f barleo e y semi-dwarf mutants, when measured in tissues as diverse as the coleoptile and the peduncle, cell numbert celno l t length,bu e closels founb , wa o t d y associated with final plant height. . 2 Cell size withi a tissun however, is e , closely relateo t d the extent to which that tissue has elongated. Thus the relatively short GA3 insensitive coleoptiles of some mutants have smaller cells than those found in the longer GA3 sensitive coleoptiles d relativel,an y short peduncle e alsar s o associated wit a decreash epiderman i e l cell length. 3. The better lodging resistance of evecto-ldes over semi- prostrate mutants cannot relat o differencet e celn i s l number, but might be associated with structural properties of the stem (and possibly roots) that are a function of cell size.

Acknowledgement This wor s carriekwa whilt e senioou d th e r author hela d Cooperative Awar Sciencn i d d Engineerinean g postgraduate studentship between the Genetics Department, Cambridge University and the Plant Breeding Institute.

5. REFERENCES {1} SILVEY, V. The contribution of new wheat, barley and oat varieties to increasing yield in England and Wales 1947-78. Journal of the National Institute of Agricultural Botany IS (1981) 399. } NILSON{2 , E.B., JOHNSON, V.A., GARDNER, C.O. Parenchyma and epidermal cell length in relation to plant height and culm internode length in winter wheat. Botanical Gazette 119 (1957) 38. {3} ALLAN, R.E., VOGEL, O.A., BURLEIGH, J.R. Length and estimated number of coleoptile parenchyma cells of six wheat selections grown at two temperatures. Crop Scienc e(19622 ) 522. } KLEINHOFS{4 WARNER, ,A. , R.L., MUEHLBAUER, F.J., NILAN, R.A. Induction and selection of specific gene mutations in Hordeum and Pisum. Mutation Research 51 (1978) 29. {5} MYHILL, R.R., KONZAK, C.F. A new technique for culturing and measuring barley seedlings. Crop Science 1 (1967) 275. {6} BURTON, K. A study of the conditions and mechanisms of the diphenylamine reactiocolorimetrie th r nfo e estimation of DNA. Biochemical Journal 62 (1956) 315.

28 {7} GILES, K.W., MYERS, A. An improved diphenylamine method for the estimation of deoxyribonucleic acid. Nature 206 (1965. )93 } WETTSTEINN HAAHR{8 VO , ,V. . ,StudieD inducedn a f so , high-yielding dwarf-mutant of spring barley. In 'Barley Genetics III' ed. H. Gaul (1976) 215. } ALI{9 , M.A.M., OKIROR, S.O., RASMUSSON, D.C. Performance semi-dwarf o f barley. Crop Scienc (19788 e1 ) 418. {10} ULLRICH, S.E., NILAN, R.A., BACALTCHUK . ,PlanB t height improvement in barley. In IAEA-TECDOC-268 "Semi-dwarf cereal mutants and their use in cross breeding" (1982) 73. {11} WRIGHT,S.T.C. A sequential growth response to gibberellic acid, kineti d indolyl-3-acetian n ce whea th aci n ti d Coleoptile (Triticum vulgäre L.). Nature 19O (1961) 699,

29 PROGRES EVALUATIONE TH N SI BREEDINGN I E US , , AND GENETIC ANALYSIS OF SEMI-DWART MUTANTS OF BARLEY*

S.E. ULLRICH, C.E. MUIR Department of Agronomy and Soils, Colleg Agriculturf eo e Research Center, Washington State University, Pullman, Washington, United State Americf so a

Abstract

Breeding for reduced height In barley (Hordeum vulgäre L.) to primarily reduce lodging susceptibility Is ongoing In the Washington State University barley breeding program o semi-dwarTw . f winted an r spring cultlvars have been released and a number of advanced lines are being considere r releasefo d . Several semi-dwarf source e utilizedsar ,

including those from induced mutant n 'Jotund i s rol an i 'P l,ne

1 1 'Valtlcky' additionn I . , ove0 putativ20 r e mutants have been selected e pasith n t four years fro 2 sodiuM m m azide-treated population f locao s l cultivar d advancean s d lines. Thes e evaluateear e pedigreth n I d e breeding program and some have been incorporated into male sterile facilitated recurrent selection populations develope r reducefo d d height. The Inheritance of dwarfism In one mutant in the cultivar 'Advance s determinewa 1 e controlleb o t da singl y b d e recessive gene. Introduction evidens II t t from reviewing breeding program d frosan m evaluating uniform regional nursery entries, that decreasing plant height primarily o reduct e lodgin a majo s i gr goa barlen i l y (Hordeum vulgär) L. e cultivar developmen e Uniteth n I td States. e Thi truth s i sn i e Washington State University (WSU) program when considering culitvarr sfo

* Scientific Paper No. 6341. Project No. 1006. Some of this research conducted under IAEA Research Agreement 2690/R1/CF.

31 production In both the Irrigated and higher rainfall non-Irr i gated

areas. The objectives of this presentation are to relate the progress in semi-dwarf cultivar development and semi-dwarf mutant selection and evaluatio t WSUa n . Advanced Breedi ng Progress Several semi-dwarf type e include ar se lis th f barle o tn i d y cultivars commericialIy produced in Washington and the Pacific Northwest. Amon e sprinth g g types e 'Advance',ar , 'Kombar' d 'Gusan , ' and winter types include 'Boyer', 'Hesk' and 'Mal1. These were described earlier CO. Among the new lines under advanced testing in e V/Sth U breeding o prograsemi-dwarftw e ar m s (Tabl . SelectioI) e A W n 10698-7 2-roa s i 6w malting type resulting fro crosa m s between Klages and a line derived from the Induced semi-dwarf 'Valtlcky' mutant [2l.

TABLE* I. AGRONOMIC PERFORMANCE OF ADVANCED SEM I-DWARF BARLEY LINES AND

CULTIVAR CHECKS, 4 LOCATIONS IN EASTERN WASHINGTON, 1980 AND 1981

Cultivar/e !in Type Plant height Lodging Yield -cm- -%- • -kg/ha- WA 10698-76 M , 2 , S 71 0 5200 Advance S,6,M 86 4 4900 e pto e t S S,6,F,C 91 10* 5100 WA 2905-75 W,6,F 77 13 5500 Boyer W,6,F 92 23 5000 Kamiak W,6,F.C 98 30 4400

Type symbols spring= :S Winter= ;W 2-row= ;2 6-row = ;6 ;M malting; F = feed; C = normal height check

32 The other selection, WA 2905-75, is a winter feed type derived from a semi-dwarf Selection, 68-1448, from the U.S.D.A. World Collection. The agronomic performance in Washington of these lines is compared with normal height check CSteptoe' and 'Kamiak') and the most grown semi- dwarf cultivars (Advanc d Boyeran e Washington i ) e nline Th (Tabl s. I) e have performed well in trials thus far, showing good lodging resistance and yield A numbe. f otheo r r less advanced semi-dwarf lines froe th m pedigree breeding program are in tests also, with a number of semi-dwarf sources represented including 'Jotun', n 'Beracinducea d an 1d 'Pirol ine' mutan - AnothetCO r breeding approac hU breedin WS employe e th gn i d program is male sterile facilitated recurrent selection, MSFRS C33 Crossing and selecting was commenced In 1982 In a number of populations including Composite Cross XXXII intentionally compose f short-staturedo d barley- CO s From recent research conducted at WSU, it was concluded that the semi-dwarf source r sbreedin ou use n i d g prograt causno d e di mstan d establishment problems suc thoss a h e experienced with some semi-dwarf wheats £53. Even when coleoptlle length f semi-dwarfso s were significantly shorter than thos f taleo l cultivars, field emergence rates and final stands were not adversely affected (Table II). Correlation coefficients between coleoptlle length and stand establishment traits and plant height and stand establishment traits were generally non-significant. Mutant Selection and Evaluatlon r severaFo l years semi-dwarf mutants have been selecte 2 sodiuM n I d m azi de-treated population f establisheso d cultivar d advancean s d breeding line f gooso d yiel d qualitan d y potential. Table III depict e numbesth r of putative semi dwarf mutants selected in various spring barleys In 1980 and 1981. The number of mutants selected as plant rows and advanced to

33 o>-<- cu OX X I I T3 13 X: xi rr;^3 er. -c~o o u u cnx: ro XI CM— o o c o - j r\ w f - o ,•*r r -* m es) L. •«?vCOr^r^c-ju~\c»\ococOK^ ITl CL CO i/7 CT M^ ^ C* u M* ^ f C0 ï M1 i^ n i M ' r ^ •o co c Lu m J T U DJ 3 T •O O) .s: uuuuuxt'oxtxiu in en C Xt X) XI XI X) (D U O ID J3 "O (D O c •— '»cr>\CTr»'ïir>r~rNjOK> 0 O aI.. tOCNCaOCSIKstNCMCNOOttO ii to CL CL CO in

O I X - •« A O ) ) fl > 0 CL — 0 ( I I 3 T c I X O I 3 T I : x n i u 3 UT «o 3c — — — u •o Ki • K\ in in O co • fi CO a> a CL .C..VO.....KV* in cocr-vov cnr^cncoco— » r o— CO îc 4- in x: u u •o o 0> U I XX I I XX I I XX ) I XX >

10 g n O O) U XI 0 < - H ) O > X D ( > O ^ gg in •o o Oî»-r-«fMt»-'O®T>ir> o> a c (0 O a. r^c^intn • «omr-o «o r- 10 in JK co i_ « — co « u 4- — o o c -O T3 J3 J3 •*- XI J3 "OU) •*- in ' 4- a M C M C n i Cô Mô rn ~i C •» CL V CO 0) O l— i H- in € o o !_ o u > t o u CM T3 0> X C •O IO Ut • •««£»•••••. • fl) O) O "to X — IO CM o -o O LU O) •o c <0 CL .••»••••••*. • — X CO L. 4- «I x: u o uT u IO — «9 U 3 T I X>X CO — en na t (OXITU J • ' a

• •••«••••••ft • o in CL a> co o> o aX •a « en o u -o o u u £ s» XtXIXIXIXIUXlXt f I X I a e in m § re • ••••••••••• • i_ f"* U^ (N< <^ ^^ ^0 f"^ \Q \Q \f\ «••• <^ C^ in n L •o a c •o ^ «• r». c a •5 (D t. » X t X I X O J I X Q J I X o 2 a> a

u. • ••••••••*••• • » * 2 CL a a> • o % tf 4 C* ^ f 3 ^ t of""*3 O ^ C * î**~ ^ * ^ ^ • *" | Ps ^ ^ ^ GO — •O M •o £ o> o I

CLf •o a, o +- III XI I XI I -4-11 c to ffi O) en c o c r»tor»cor—f-i^r^of-r-r» «•o 0» 4- a - c So f — CO wl t +• E uO —Ok o> I o> f o To3 c e s - « o u a - i - r c u « i- J « X U - -t B ( > ) 0 1 . > - C „•£ o> o locxtr^jCM— o. (o ^ « xi C T3 8 (O o 9 _ o o • + —n 0) o in i! a r n in in/twin «AS win ~~uat Z a LU CO o I 34 TABLE III. PUTATIVE SODIUM AZIDE INDUCED SEMl-DWARF SPRING BARLEY MUTANTS

SELECTE 198N I DD 198 0AN D THEI AN 1 R DISPOSITION

Parent cultlvar/ Mutants Di sposi tion 1 ine Type se 1 ected Rows Pre . yiellIm d selected trial entries

1 IW . 1980 Advance 6-row 32 17 12 Morex 6-row 10 4 2 WA 9037-75 2-row 28 9 4 WA 9044-75 2-row 30 12 5 1981 Crée 6-row 3 1 Dickson 6-row 7 3 Manker 6-row 29 11 Andre 2-row 2 1

preliminary yield trials are also Indicated. In 1982, again a number of putative semi-dwarf mutants were selected In 8 spring cultlvars and

lines. Short plants have readîly occurred tn the M2 populations and selection has been based on relatively good agronomic appearance in addition to plant height. Straw strength, fertility, and head type have been major factors In selection. Some of the selections have been of e erectoideth s type most ,bu t have not. Selectio evaluatiod an n f o n semi-dwarf mutants continues in the WSU program. Several of the newly selected sem!-dwarf mutants have been cross bred with other breeding lines and culitvars. Inheritance of the seml- e mutant e dwarth variet th f o n f i s e ytrai on Advancn i t s determinewa e d

35 tal e 2 fro o icrossesF nth ltw m o e crost tin A 12336-7s On W .e s wa 7 darker x Blazer). The F£ frequency distribution for plant height was

continuous, but two distinct populations (height classes) were apparent . Assumin(Fig1) . g that Advance itsel a semi-dwarf s i f o semi-dwartw , f genes should have segregated in a 9:3:3:1 ratio as the result of this cross. However, if additivity did not occur and one gene was epistatlc r 9:3:o ove e other7 4th r 9: rati a , o would occur. Since normal Advance (87 cm) was closer in height to Sel. 12336-77 (94 cm) then to the Advance Dwarf (53 cm), a 9 (Tall) : 3(Aa'vance type) : 4(Advance Dwarf type) rati mors i o e likely, wit e tald Advancth han l e type genotypes blending togethe e populationth n i r e resulTh . t woula 12: e b 4d (3:1) ratio. Separatin e populationth gm resultec 0 n acceptabl7 a n t i a ds e 3:1 ratio (Chi-square analysis P=0.05). The second cross analyzed was a backcross to Advance. The Fj plant height frequency distribution was again continuous in which two distinct populations occurred (Fig. 2). Separating the distribution at 70 cm resulted in a 3:1, normal :semi- dwarf ratio (Chi-square analysis P=0.05). Base n theso d es wa dat t i a concluded that this Advance mutant has a single recessive gene for semidwarfing. Again assuming that Advance is a semi-dwarf, it appears that additivito n y betweeo dwarfintw e nth g sources occurree geneth d s an d involved are independent. Incidently, 10 and 27 Fj plant rows from the WA 12336-77 and Advance crosses, respectively, were selected in 1982 for advancemen e breedinth n i t g program. Genetic.analyse f semi-dwarso f mutants induced in the WSU program will continue.

36 ADVANCE DWARF x SEL. I2336-77 60r

52 n = co 36 Q. fe 28

UJ 20 00

1 12

0 40.1 45.1 50.1 55.1 60.1 65.1 70.1 75.1 80.1 85.1 90.1 95.1 100.1 105.1 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 -K» -110 PLANT HEIGHT (cm)

Fig. 1. Plant height 12 frequency distribution from the cross Advance

Dwarf x Sel. 12336-77 darker x Blazer). The mutant and normal

parents' plant height were 52 and 94 cm, respectively.

ADVANCE DWAR Fx ADVANC E 60

44 185 n= CO

! 36 CL fc 28 tr £ 20

1 .2

0 40.1 45.1 50.1 55.1 60.1 65.1 70.1 75.1 80.1 85.1 90.1 95.1 KJO.I IO5.I -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -K» -105 -110 PLANT HEIGHT (cm)

Fig . 2 .Plan t heigh F t frequency distribution frocrose th m s Advance » 7 ^ Dwarf x Advance. The mutant and normal parents' plant heights were 54 and 87 cm, respectively. 37 REFERENCES

O ULLRICHC , NILAN , E. BACALTCHUK A. . . S , R , , "EvaluatioB. , d an n

genetic analysts of semi-dwarf mutants of barley", Semi-dwarf

Cereal Mutants and their use in Cross-Breedlng, (1981), IAEA-

TECDOC-268, Vienna. 73 ,

[2] HAAHR, V., WETTSTEIN, D. VON, »Studies of an induced, high-yielding

dwarf-mutan f sprino t g barley". Barley Genetics III, Procd 3r .

Int'l Barley Genetics Sympo. (GAUL , Ed)H. ,, Thtemig, Munich (1976)

215.

£33 RAMAGE, R. T., Comments about the use of male sterile facilitated

recurrent selection, Barley (19814 New2 . . sI 52 )

[4] RAMAGE, R. T., THOMPSON, R. K., ESLICK, R. F., Release of Composite

Cross XXXI I, Barley News I. 12 (1976) 9.

Ü BACALTCHUK[5 , ULLRICHB. , StanE. . S d. establishment

characteristics of barley genotypes of different plant heights,

Crop Sei. 21 (1983).

38 PROGRES EVALUATIONE TH N SI BREEDINGN I E US , D AN , GENETIC ANALYSI SEMIDWARF SO F MUTANT WHEATF SO *

CF. KONZAK, M.R. WILSON, P.A. FRANKS Departmen Agronomf o t Soilsd yan , College of Agriculture Research Center, Washington State University, Pullman, Washington, United States of America

Abstract Studies with induced mutant semi dwarf f wheao s t indicate that some reduced height genes have goo dbreedingn i potentia e us r . fo l Most common wheat mutant semi dwarfs studied so far require some modification through crossin d reselectioan g t thosbu nf duru eo m show more promis r direcfo e t use. Simple genetic test crosses indicat e induceth ef o dtha l mutanal t t semi dwarfing genes (reduced height = Rht) so far tested for all el ism segregate independently of the 'Norin 10' semi dwarfing factors Rht, and Rht9. The mutants tested include Karcagi 522M7K, Karlik 1, and Burt M8"6~6. Earlier tests indicated that Marfed Ml (CI 13988), Magnif 41 Ml (CI 17689), and Burt M937 (CI 15096) carry single semi dwarfing genes also independen f thoso t e from Nori . Transfe10 n e induceth f ro d mutant semi dwarfing genes to a common spring wheat background, 'April Bearded1 I 7337) progresn (C i s ,i f near-isogeni o o develo st t se a p gent Rh ce tester stocks.

. 1 INTRODUCTION Induced mutants with reduced height have yet played a limited role in the development of new, high yielding, lodging resistant wheat cultivars by recombination breeding. Even so, as productive reduced height mutants or their improved cross-bred derivatives become more readily available, there is already evidence that wheat breeders will exploi e desirabltth ther fo m e attribute sd sprin re the y havee gma y Th .whea t cultiyar 'Siriuss 'wa developed in the Federal Republic of Germany by crossing an induced short straw mutant with an experimental line. This cultivar achieved commercial Unitestatue th n di s Kingdom, BRD, Luxembourg Francd ,an e [1] seemt ,bu o st have had little further use. More encouraging, however, is the evident potential of Karlik 1, a reduced height mutant induced in the USSR. While never exploited directly, Karli s alreadi 1 k parena y f threo t w higne eh yielding hard wintere d r wheat cultivars, 'Odesskaj d 'Odesskaian * 75 a a Polukarlikovaja1 developed and released in the USSR [2], and Mv 8, develope released an d Hungarn i d y [3]. Interestingly, Karli , induce1 k d using nitrosomethylurea, was the female parent of all three cultivars. Because this mutant has been distributed widely over the world via the International Winter Wheat Performance Nursery program, it likely will prove increasingly importan reducea s a t d height gene n sourceow r Ou . preliminary genetic breedind an s g studies suggest that factn ,i , Karli1 k does have a good plant type and evidently no serious negative traits that

* Scientific Paper No. 6490. Project Nos. 1568 and 4029. Some of this research was conducted under IAEA Research Agreement 2690/R1/CF.

39 canno e compensateb t r readilyfo d . Odesskaj a vigorous s i 5 7 a , strong strawed, semidwarf cultivar with high tillering capacity, large hard red grains, improved spike size and productivity compared with Karl i k 1. No doubt these derivatives will prove even bette s parenta r r furthefo s r breeding. In durums, the potential is equally or even more promising. 'Castelporziano' (PI 347731), a reduced height mutant Cp B132 from 'Capelli', was released as a cultivar in Italy [4] and has since become a o cross-breparentw f o t d cultivars, 'Tito d 'Augustoan ' Italn i ' y [5,6], and three cultivars, 'Miradur1, 'Attila', and 'Grandur' in Austria [7,8,9]. Castelporziano supplie e cytoplas o th (Augustod tw r fo m , Miradure th f )o five cultivars. Our experience also indicates that Castelporziano will be a widely useful reduced height gene source for cross-breeding, and the derivatives suc s Attila h d Granduan a r should prove even bette s gera r m plasm. Several reduced height mutants of durum recently induced at Pullman likewise seem promisin r breedingfo g , includin 6521A W g , registered under the name 'Cargidurox n behalo 1 f Washingtoo f n State Universitr fo y production in France, by Gavadour-Cargill [10], and more recently from 'Edmore' (CI 17748) and 'Vie' (CI 17789) now in field trials. Our past experience using semidwarf mutants of the hexaploid wheats induced at Pullman has so far not proved as successful as hoped. Perhaps ia largn e measure this beeha sn becaus e havw e e produce o many—wels d l over 200 [11]—and have invested considerable effort evaluating them and learning ways to single out those which may be most promising for breeding. Thus, the indications shown by our earlier genetics studies of some mutants have not as yet materialized in the development of a cultivar competitive with those carryin e Rhtth gr Rht,o « alleles from Nori0 1 n derivatives. In fact, most of the mutants we singled out for breeding and genetic studies have appeared to carry undesirable features as background or associated with the mutant gene along with their desirable attributes. e mosth t r partFo e undesirabl,th e features have been difficul o modift t y through recombination breeding [12]. It appears now rather likely that we may have selected for exploitation mutants that were too dramatically changed, since our current experiences offer greater encouragement that the mutant w includeno s n breedini d g experiments wil e exploitablb l futurn i e e cultivars [13,14]. This paper describes recent progres breedinn i s d genetian g c analyses with some promising semidwarf hexaploid wheat mutants.

2. MATERIALS AND METHODS 2.1. Genetic and breeding stocks—origin and description Most of the studies discussed involve analyses of the mutant Karcagi 522M7K which is a reselection from a genetically unstable line obtained originally from Viglas Hungarn i i y [15]. Karcagi 522M7 s induceKwa y b d gamma irradiatio y seeds dr e mutan f Th o .nculms ha t s about three-fifths the length of those of Karcagi 522. Its spikes are long and lax, but its culm e largear s diametern i r , more spreadine leave e baseth th d st ,an a g are thicker, wider, and darker green than those of Karcagi 522. It also is later maturin highls i d yan g susceptibl o stript e d leaan ef rusts, thouga h comparison with the parent stock has not been made. Burt M864569A 0(W s induce )wa Washingtot a d n State University using gamma irradiation and first described in 1966 [11]. Burt M860 had received little attention previously because it was obviously a multiple mutant. Besides its semidwarf trait, it also has a dense wax bloom on its spikes

40 and reduced winterhardiness, therefore a lower yield performance. However, Burt M86 s long 0ha x spike la , s abou tparens equait o tt l stock, good straw strength d generallan , y good plant type traits. Some other stocks used in genetic or breeding studies reviewed here e brieflar y describe Tabln i d . I e 2.2. Breeding studies The mutant Karcagi 522M7K was crossed with the tall, hard red winter wheat selection KS 745826 and F« plant heights based on the length of the longest culm were recorded. Thfs cross was made also to improve the genetic backgroun reducen i d d height derivative f Karcago s i 522M7KA . large sample of both tall and semi dwarf rust resistant single plant progenies was grown in F^ and a selected sample grown as spike progenies 3 iF n Reselections were made in lines from crosses involving the semidwarf mutant Magnif 41 Ml described earlier [2,3]. Additional new crosses have been made with this mutant, but segregation details from those crosses were not recorded. 2.3. Evaluation of genetic dominance relations of Karcagi 522M7K Crosses with Karcagi 522M7K were made by one of us (PAF) using as female parents a series of the tallest available hexaploid wheat accessions, as well as four triticales differing in plant height. The F, and parental plant heights were recorded. 2.4. Gene interaction studies Additivity, dominance, epistasis d interactionan , s among reduced height and possible increased height genes are being investigated in the Fo and later generations of some crosses, mainly involving Karcagi 522M7K and Burt M860. 2.5. Height measurements Plant height, actually culm height s determinewa , o waystw n :i d 1) length of the longest culm on each plant and 2) estimated average culm maturl lengtal f eo h culm n eaco s h plant e estimateTh . d culm lengts wa h used primarily as supporting information, but occasionally segregation patterns have been more easily recognizable from the estimates. 2.6. Constructio f neao n r isogenic stocks s agreeA e drecen th upo n i tn FAO/IAEA meeting, promising mutant semi dwarfing genes are being introduced into a single line of CI 7337, a tall, late, semi-spring wheat, April Bearded e receiveW . d recently also stock f Rhtso p Rntg e ApriRhtd th ,an n l, i Bearded background, . GaleD . M ,share Plan. Dr dty b witBreedin s u h g Institute, Cambridge.

3. RESULTS AND DISCUSSION Intensive investigation progresn i e ar s s wito inducetw h d mutants, Karcagi 522M7K, a hard red winter wheat, and Magnif 41 Ml (CI 17689), a hard sprinre d g wheat. Thes o mutantetw s show unusuan i l e promisus r efo breeding. However, neither is yet available in a polished genetic

41 TABL . I ESOM E OTHER STOCKS USE BREEDINN I D GENETID AN G C STUDIES

Name or Other Market GA, Coleoptile Method of Accessio. No n Identification Rht Genets) Class1 Response Length2 Breeding Origin

CI 12696 Burt rhtg HWW + ML Cross WA CI 15076 Bur t M937 rht^ rhtg HWW + ML Y- induced WA

A76-545 m Thumb/7*BurTo t Rht3 rhtg HWW VS Backcross WA CI 17776 CI 13438/Burt 937, Sel. 87-Rht,1 ? HWW + M Cross WA X

CI 14483 Coulée Rht0 rhtg HWW S Backcross WA CI 13438 Sel1 10 . Rhtj (rhtg?) HWW S Cross WA

4k CI 17689 Magnif 41 Ml Unidentified HRM S -l- MNH induced WA N» KS 745826 SD 69103/Atla0 s5 None HRW + L Cross KS — Kar1 k li Unidentified HRW ? ? MNH induced USSR

PI 428521 Hobbit Rht2 +? SRW S Cross UK CI 15267 Marzotto Rhtg? +? SRW + M \ Cross IT CI 7337-UK April Bearded None HRI + L Cross? UK white» M = spring r ,S o winte= d hardM ,= re = H r ,R (strongly responsiv o vernalization)t e . 2 VS = very short, S = short, M = medium, L = long. mutane Excepth r t tfo semidwar I 17869f(C Magnil M ) 1 describe4 f d earlie semidware rth [12]f o l f,al plan t types described above have notably shorter leaves at the seedling and/or tillering and later plant growth stages as compared with taller phenotypes or parental stocks. background suitable for effective use in recombination breeding. The Karcagi 522M7K mutant appears to have good potential if its associated wide, thick leave d tendencan s y towards spreading e changedgrowtb n ca h . This mutant is distinguishable throughout the season by its leaf characteristic d growtan s h pattern e originaTh . l mutant stoc s alsi k o highly susceptible to local forms of both leaf and stripe rust. In contrast e Magnil mutantM th , 1 4 f , which likewise shows promise for breeding, carries some undesirable features also present in the original Magni 1 unde4 fr environmentou r s maiw It lo n. s defecit s i t numbe f fertilo r e florets/spikelet d thian , s trai s wel a ts incomplet a l e grain filling and tough glumes are common in its cross progeny. However, an unusual feature of this mutant is that its reduced height trait is not evident until near spike emergence. Moreover, unlike most reduced height mutants, the Magnif 41 Ml plants do not have shortened leaves, nor is the peduncle unusually shortened as might be expected, compared with Norin 10 derivatives carrying RM, or Rhtp [13]. Genetic and breeding studies with this mutant were described earlier [14], therefore, onla y brief mention wil e mad b lf mor o e e recent research with this mutant semi dwarfing source. 3.1. Use in breeding As yet, only a limited number of crosses have been made between the two mutants and locally adapted, high yielding spring wheat lines. Karcagi 522M7 s beeha Kn crossed wit S 745826K h ,higa h protein, strip d leaan ef rust resistant, tall hard red winter wheat line obtained from Dr. E. G. Heyne, Agronomy Department, Kansas State University, Manhattan. KS , Crosses of spring wheats with Karcagi 522M7K have so far not produced anything of interest, largely because of the very strong winter habit trait e mutantth f o . However, recent crosses have included more strongly spring types in an effort to overcome that problem, while the near-isogenic stocks being developed in April Bearded background should provide a back-up. The cross mentioned above with Kansas hard wintere d r wheat, managea s a d selecte * bulF d k population, doe f sinteresto appeae b o t thit rA . s stag f advancemeno e t appeari t s that this cross shows evidenc f moro e e recombination than first estimated on the basis of the F2 results, which showed a strong 3 semidwarf to 1 tall segregation (Fig. 1). Observations on F-, and F. progenies indicate that infrequent recombinant plants can be isolated which are either shorter or taller than the original Karcagi 522M7K t non,bu e appeae talleb o t rr thae talth nl parent S 745826,K n I . som . plantF e s there reductioa appear e b o t sn lea i n f widtht bu , assuranc n thieo s point must await further progeny line tests. Perhape th s most important new information from the f* progeny observations is the modifiability of this mutant. More erect recombinants occur, but all of e shorth t progeny appeae late-maturinb o t r g like Karcagi 522M7K, indicating the need to incorporate also earliness genes as modifiers. The new results suggest that Karcagi 522M7K germ plasm can be improved through recombination and selection, and that the mutant likely can be made useful in breeding. Considerin e numbeth g f improvemento r e madeb o ,t s however, it is not surprising that few if any plants yet recovered carry the desired changes. The mutant Magnif 41 Ml has been used in several spring wheat crosses f whico o h tw , were subjecte o intenst d e selectio d reselectionan n . These crosses included either the Rht; or Rhtp sources of semi dwarfing, however, and we are optimistic tnat it will be possible to isolate a high yielding two-gene, short semidwarf type for use under irrigation. There is yet a possibility that some of the better yielding, single gene, semidwarf height reselections isolate y carr mutane ma d th ygenet Rh t . 43 901- KS745826/Karcagy 522M7K 80

70 7 57 n=

K 60

of 50 U_ O Oi 40 mLU 30

- 10196 -- 10691 - III86 - - 11681 - 12176 - - 12671 - - 13166 - -61 - 56 - 51 - 46 - 41 - 36 0 5 13 0 13 5 12 0 12 5 11 0 11 5 10 0 10 5 9 0 9 5 8 0 8 5 7 0 7 5 6 0 6 5 5 0 5 5 4 0 4 HEIGHT OF LONGEST CULM (cm) Pig. 1. Segregation for culm height in F_ of the cross KS745826/Karcagy 522M7K. Average height of KS745826, 115 Karcag, cm y . 522M7cm 2 6 K

New crosses have been made with this mutant to improve it as germ plasm before its further use in cross breeding. Recombinants from the earlier advanced crosses are being used intensively in breeding. GA sensitivity tests can be used to determine if the Magnif 41 Ml mutant trait is carried y lineb s shorter than typica r Rht.fo l d Rht.an p 'single gene1 semi- dwarfs t talle,bu r than 'two gene1 semi dwarfs, since onle Rht.th y d .an Rhtp genes in these crosses are associated with GA3 insensitivity. However, evidenc f progreso e effortn i s o improvst e backgrounth e e th f o d Magnif 41 Ml mutant Rht gene is already available, since several new semidwarf derivatives of a cross with 'Mahratta1 (CI 8500) have been recovered which have yielded competitively witr highesou h t yielding local cultivars bot 198n i h 1 (one test 198d )an 2 (four tests). Because these selections carry no germ plasm from locally adapted materials, we are optimistic that their potential can be exploited effectively to achieve yield advances in further recombination breeding. 3.2. Construction of near-isogenic stocks e numbeTh f genero s controlling plant heigh differenn i t t genotypes may vary and thus complicate and reduce the precision of test cross analyses. Therefore, to obtain better materials for genetic and other studies, we have initiated work to develop Rht gene tester stocks in a standard spring wheat background. Beginnin 1981n i g , crosses between a n April Bearded (CI 7337) selection provided by Dr. M. D. Gale and the

44 semi dwarf stocks Karcagi 522M7K, Marfed Ml (CI 13988), and Magnif 41 Ml (CI 17689) were made. The first backcrosses were completed in 1982 and at leas o mortw t e backcrosses wil e madb l e before selections wil e takeb lr fo n preliminary test crosses. Additional Rht genes, including those from mutant stocks, Burt M93I 15076(C 7 ) with rht. plus rht,. Burd an ,t M86 4569A gent 0(W rh e ) w pluwitne sa h rht weTTas ß,a s BurI (C t 12696) with rhtg, wil e introduceb l d inte Apritn o l Bearded background e opportunitth s a y allows. Apri n ideala Beardet l no sprins i d g whear fo t r purposeou , however, sinc t seemi e o havt s a strone g vernalization response in our environment. 3.3. Genetic studies 3.3.1. "Test" crosses with stocks carrying other semi dwarfing genes The Karcagi 522M7K stock and several other mutants were crossed with each other and with sources of genes Rht,, Rht0, and Rht,. The F, and F~ of these crosses have been '""•""™grownj . ^ .""" ' Als"'"£ o included in the crosse e Marzottoar s , representin e Italiath g n semidwarf type which differs from the Norin 10 types [16], the Bezostaja mutant Karl i k l, and Burt mutants M860 and M937 (rht.), but measurements on the Fp plants have not yet been analyzed. TaBle II presents observations on the F~ which suggest independence of most of the Rht gene combinations. Only in the cross Burt M860/Burt M937 is there a suggestion of an Rht gene association, and this may be an artifact caused by a chromosome structural alteration, because in some crosses of Burt M860 studied earlier, F progeny with sterility or reduced vigor were observed. 2 Earlier studies [13,14] showed that the semidwarfing genes carried by Burt M937 (CI 15076), Magnif 41 Ml (CI 17689), and Marfed Ml (CI 13988) differ from Rht, and Rhtp. Because Rht, and Rht., are closely linked e mutanth , t genes must also differ genetically from Rht,. e resolvinTh ge crosse poweth f o rs studied her s limitedi e t bu , useful information on probable genetic associations and on dominance was obtained. Genetic interrelationships, especially with regar o additivitt d y and epistasis, should be more evident when the culm height data are available. 3.3.2. Tests of dominance and additivity e generallTh y reduced heighplant, F f o ts from crosse f Karcagso i 522M7K/tall whea d triticalan t e stocks indicate t gensRh ethae th t present in this new semidwarf mutant is unusually dominant (Table II). w casesfe a Onl ,n i ye.g. , crosses witwheae th h t 'GorkowschankaI (P ' 294987o triticalestw d )an R 623 possibld ,CZ ,an y 'Ouanillo 168' thers ,i e evidenc , planeF thae tth t heigh greates i t r tha e Karcagn th tha f o ti 522M7K line, suggesting that even heterotic effecte tallnesth f so s alleles generall e suppressedar y . Moreover 2 population,F s from most crosses with Karcagi 522M7K, including those described in Table II, but also others still under investigation, show high frequencies of short plants and low frequencies of tall plants, as expected in the segregating progeny of a strongly dominant reduced height gene source. Even so, the Rht gene in Karcagi 522M7K still is subject to epistatic effect f co-dominanso t alleles, including possible height- increasing alleles present in some genotypes. This is indicated by results fro smala m d latelan number« F generatio f ro n population e havsw e observed (not shown) which support the evidence for infrequent intermediate height F^ progeny. Thus, in certain F« progenies of crosses with tall

45 TABLE II. OBSERVATIONS ON F POPULATIONS FROM CROSSES BETWEEN SEMI DWARF OR SHORT STANDARD HEIGHT STOCKS

Rht Factor Genetic Cross Dominance Association Observations, Conclusions

Karlik 1/Karcagi 522M7K Rec + Dom No Low frequency tall, double short; independence Reciprocal Dom + Rec No do

Kareagi 522M7K/Burt (rhtgplantw fe , )s do taller o thaN n Burt c ; DoRe m+ independence

Karcagi 522M7K/Tom w tailsThumb/7*BurFe , doubl o N te (Rhtshort 3m ); Do independencf - m Do e Reciprocal o d o N m Do Do m+

Marzotto (Rhtg?)/Karcagi 522M7K o N Som m ReceDo segregant?+ s talle r shorteo r r than ON parents; independence

Burt M860/Karcagi 522M7K Rec? + Dom No Some segregants taller or shorter than parents; independence

Karcagi 522M7K/Burt M937 (rht o N j Som ec Re segregant + m Do s talle r shorteo r r than parents; independence

Coulee (Rht2)/Karcagi 522M7K o + N Semi m -Do Some segregants talle r shorteo r r than m Do parents; independence

1 (Rht^/Karcag10 Sel. i 522M7K Dom + Semi- No Some segregants taller or shorter than Dom parents; independence

Karcagi 522M7K/Hobbit 2 gen g e Se short, independenco N Semi- 4 m - Do e Dom

Burt (rht,)/Karlik 1 o N Some segregant c Re 2 s taller, some shorter than parents; seg. grass clumps; independence TABLE II (Continued)

Rht Factor Genetic Cross Dominance Association Observations, Conclusions

Karlik I/Coulee (Rhtp) Reo N + Semic - Some segregants taller or shorter than Dom parents; independence Karl i k l/Sei. 101 Rec + Semi- No Mostly taller than Karlik 1, none as Dom tal s Burta l w shorte,fe r than Karlik; more tha gene2 n s seg? Burt M860/Burt M937 (Rht.) + ? c Re 2 Very few Burt height, seg 2 gene short; linkage or chromosome aberration? Burt M860/Coulee (Rht,)* Rec + Semi- — ? Se gen2 g e short w Bur,fe t height; Dom linkag r chromosomo e e aberration? Burt M860/Burt 1 Rec w grasfe sg Se clumps, mostly Burt height, 1/4 M860 height; single rht gene + D (grass clump dwarfing) gene? Burt M860/Sel. 101 (Rhtj)* o Semi1 RecN , - Seg 2 gene short, few Burt height; Dom independence, some aberrant plants identified reduced height genes ;reducea d height gene presen Marzottn i tRhte b s reporte a py oma r fo d Sava and Mara (Gale et al. [20]), since their semidwarfing traits have a common generic origin (see Dalrymple [16]). parents, plants of intermediate height also are present, and in one combination R 1215/Karcag6E , i 522M7K (6ER . 121121No 5= Braunschweig Wheat Genetic Resource Collection), the frequency of intermediate height F 2 progeny may make up half the population. Also, the bulk-selected single spik S 745826/KarcageK progene th f yo i 522M7K populationn i w no , F4, are generally about equal in height to the parents, but some progenies include plants thae distinctlar t y shorter thae Karcagth n i 522M7K stock, and a smaller number of progenies include plants of intermediate height. Consequently, in spite of the apparent single gene segregation observe r thifo d s cros evidens si t (Figi t, .tha1) e th t backgroun e parentath f o d l stocks differ t leasa n y additionaa b st l paif o r reduced height allele t additivels ac whic n ca hd co-dominantl an y y wite th h reduced height gene of Karcagi 522M7K. Only in retrospect can it be suggested that the wide distribution of height levels among the F« progeny of this cross represents more than the effects of environmental variabilit e quantitativth n o y e expressio e planth tf o n height character. s seemA s typical alsr mosfo o t other majo genest Rh rheighe ,th f o t recombinants carrying two or more reduced height factors is less than fully additive, whereas heterotic effects seem less than with other Rht gene stocks (Table d II)an I .s 3.3.3. Test crosse o identifst y genes carrie speciay b d l lines F « populations were grown in 1982 of crosses involving an apparent Rht, gene recombinant line and appropriate testers. Line 87-1 was isolated earlier from the cross CI 13438/Burt, as a tall, Burt height line with GA insensitivity. Lin3 e 87- unusuas 1i l becausgenetis it f eo c origi d apparenan n t recombination of traits [12,13]. Later analyses [14] suggested that Line 87-1 carries Rht, from CI 13438, which is responsible for its GA insensitivity e height-reducinth t bu , g effec f Rhtto ,suppresses i y b d 3 the epistatic action of a height-increasing gene. If, as suggested, the height-increasing gen s linkei e d with Rht, d opposin,an g allelee ar s carried respectively by CI 13438 and Burt, infrequent recombinants such as Line 87-1 might carr couplingn i y o alleletw e ,th s with opposing effects. However crose ,th f Linso e 87-1/Burt segregate w plantfe a f Rhtdo s , height, whic he expecte b woule sam t th eno df i d'tallness * allels wa e present in both parents. This may indicate that the gene responsible for the tallnes f Linso e 87- y hav1ma e been introduced intcultivae th o r from another source by a chance outcross or that it came from CI 13438. At this stage, height measurement n singlso et precis plantno e ar es enougd an h influence y heterotib d c effectsdifficuls i t i o o ,determins t plantf i e s taller than Burt also have e populationsegregateth n i t e crosou dTh . f so Line 87-1 with 'Coulee1, a related Rhtg carrier, segregated plants obviously short enougcarryine b o t h g Doth Rht Rht,,d ,an , confirm- ing that Line 87-1 carries Rht,. However, "tfie cros f Linso e 87-1/CI 13438 also segregate w plantfe a df apparentlso y Rht, height, which likewise should not occur if both parents carry Rht,, and similarly no plants taller than Burt could be detected. The numoer of identifiable plant f Rht(o s ,o heightt w f thilo o „ so )F froto crose s mth s wa distinguish between linkag two-gena d an e e segregation, considerine th g quantitative nature of the height measurements and the strong effects of environment. More detailed data are being sought via F line analyses. Resolutio genetie th f no ccombinatioe th basi r sfo f traitno s presenn ti 3 Line 87- counterparts I 17776it 1(C d )an , tall Rhtg carrier, Lin0 2 e (CI 17775), from the cross Coulee/CI 15076 are important to an understand- ing both of the action of Rht, and Rhtg, and of the genetic origin

48 of these important height-reducing genes [16]. The height-reducing actions of Rht, and Rht2 are completely suppressed in these stocks, both extracted from studie[17]u H y ,b s whil e their associate insensig GA d - tivity is largely, if not totally, unaffected. Moreover genetia f i , c utilizatio A bloc6 o t k s nphysiologicalli y responsibl e expressioth r fo e f reduceo n d heigh carriery b t f Rhto s , and JNrt,, [18-20], then genes which epistatically suppres e reduceth s d height expression, but not the GA response, must act via an as yet unknown mechanism. We believe that further studies of Sel. 87-1 and Sel. 20 can provide usefu knowledgw e ne genetil th physiologicad n o ean c e l th base r fo s semi dwarfing phenomeno n wheati n .

REFERENCES

] [1 HOESER , WENISCHK. , , SprinK. , g wheat, Sirius, Mutation Breed. News!. 9 (1977) 14. [2] LYFENKO, S.F., ERINYAK, N.I., FEDCHENKO, V.P., SOZINOV, A.A., HEIFETS, A.M., Triticum aestivum, Odesskaja 75, Odesskaia Polukarlikovaja, Mutation Breed. Newsl (19794 J. .. 11 ) ] [3 SZILAGYI , SZALAYG. , , TriticuD. , m aestivum , Claudia8 v M , , Mutation Breed. Newsl. J.6 (1980) 17. ] [4 SCARASCIA-MUGNOZZA, G.T. linee i Du ,efrumentd o duro ottenutr epe mutazione indotta, Notiziario CNE N^ (1968 . 3 ) [5] BOZZINI, A., BAGNARA, D., Creso, Mida e Tito: nuovi grani duri dalle eccellenti produzioni, Informatore Agrari (19740 2 o . 1 ) ] [6 BAGNARA , PORRECAD. , , ROSSIG. , , L.B., Durum wheat—Augusto, Mutation Breed. Newsl. _10 (1977) 14. [7] HANSEL, H., TrTticum turgidum conv. durum, Probstdorfer Miradur, Mutation Breed. Newsl 3 (1979J. .. 20 ) [8] HANSEL, H., Triticum turgidum ssp. durum, Grandur, Mutation Breed. Newsl. _16 (1980) 18. [9] ADAM, J., Triticum turgidum ssp. durum, Attila, Mutation Breed. Newsl. 16 (1980) 18. [10] KONZAK, C.F., Triticum turgidum ssp. durum, Cargidurox, Mutation Breed. Newsl (19831 2 . ) [11] KONZAK, C.F., MILAN, R.A., FROESE-GERTZEN, E.E., RAMIREZ, I.A., "Physical and chemical mutagens in wheat breeding", Proc. 2nd Int. Wheat Genetics Symp. (Heredita , Suppl.)2 s , Berlingska Boktryckeriet, Lund (1966. 65 ) [12] KÛNZAK, C.F., "A review of semidwarfing gene sources and a description of some new mutants useful for breeding short-stature wheats", Induced Mutations in Cross-Breeding (Proc. Adv. Group Vienna, 1975), IAEA, Vienna (1976. 79 ) [13] KONZAK, C.F., "Induced mutations for genetic analyses and improvement of wheat", Induced Mutations—A Tool in Plant Research (Proc. Int. Symp. Vienna, 1981), IAEA, Vienna (1981) 469. [14] KONZAK, C.F., "Evaluation and genetic analysis of semi-dwarf mutants f wheat"o , Semi-Dwarf Cereal Mutant n Cross-Breedin i Thei d e an sUs r g (Proc. Meet. Vienna, 1981), IAEA, Vienna (1982) 25. [15] VIGLASI , Short-straweP. , d mutant f Karcago s winte2 52 y r wheat induce y gammdb a rays, Acta Agronomica (Hung. 7 (19681 ) ) 205. [16] DALRYMPLE, D., "Development and spread of semi-^warf varieties of e Unitewhea th ricd n ei an dt States internationan A . l perspective", . DepartmenUS . f Agricultureo t , Offic f Internationaeo l Cooperation and Development/U . AgencS . r Internationalfo y Development, Agr. Economic Report 455, Washington (1980C D . , 30 )

49 [17] HU, M.L., Genetic analyses of semi dwarfing and insensitivity to gibberelli hexaploin i 3 A n d wheat (Triticum aestivum e . L m Thell.), Dissertation, Washington State University, Pullman (1974) 75 pp. [18] GALE, M.D., MARSHALL, G.A., Insensitivity to gibberellin in dwarf wheats, Ann. Bot. 37 (1973) 729. [19] GALE, M.D., MARSHALL, G.A., The nature and genetic control of gibberellin insensitivity in dwarf wheat grain, Heredity J5_ (1975) 55. [20] GALE, M.O., LAW, C.N., MARSHALL, G.A., SNAPE, J.W., WDRLAND, A.J., "Analysis and evaluation of semi-dwarfing genes in wheat including a major height reducing gene in the variety 'Sava'", Semi-Dwarf Cereal Mutants and Their Use in Cross-Breeding (Proc. Meet. Vienna, 1981), IAEA, Vienna (1982. 7 )

50 PRODUCTION AND EVALUATION OF DWARF AND SEMI-DWARF WINTER WHEAT MUTANTS*

. BARABÂSZ . KERTÉSZ , Z Cereal Research Institute, Szeged, Hungary

Abstract

A special research programme for evolving and evaluating dwarf wheat forms resistan o lodgint s gwa Cereae th carriet la Researct dou h Institute, Wheat Division, Szeged, Hungary .o tal Seetw le d th lot f so winter wheat varieties Jubilejnay Partizankd an O a5 a were expose ^°Cof o o gamm dt y .ra aWit h irradiatio 1500f no 0 rad 6°Co all of MI plants grown in the field were almost totally destroyee th 1982n n i aboud I 198n i d.an % 050 t greenhouse the number of lost M]_ plants was insignificant. Only small number of plants died both in the greenhouse e fielth andn i dwhe n they were irradiated with 500O rad. treatmenA t with this lower dos irradiatiof eo n probably may hel e breederpth selection si winter fo n r hardiness. 97 dwarf wheat lines already established were analysed for height character by a top cross method using the variety Jubilejnaya 50 as a tester. Height data of the simultaneously grow2 ? d nan parenta_ F] e welth s la s la offsprings indicated that the majority of them were recessive, except 3 cases where dominant or semi-dominant dwarfism was observed. Noteworthy is the MX 158 a new semi-dwarf variety candidate, heighn 60-6i m normat 5c a t l stand and resistant to all the main diseases here /powdery milde d rusts/wan grais protei.d It an n n productior npe unit are alss i a o very good. Some genetically lesser-known dwarf sources were investigated in a complete crossing diallel test.

The importance of dwarf varieties in Hungary

The wheat production of Hungary nowadays is about three times greater than befor Secone eth d Worl lase dth t Warn I . five years average ,th e yield ranged between 4.2-4.8 metric tons/ha. The recently finished harvest in 1982 records 7-8 highese th t/hs a at yiel f farmsdo 10-1d ,an 1 t/hn i a breeding nurseries.

Research supported by IAEA under Research Contract No. 2731/RB.

51 Hungary is among the first 3 or 4 countries in the world which are able to produce high average yields for more than one million hectares even with an unfavourable distribution of precipitation. Though this quantity representr spe onle on y worle th cen df t o whea t production s importanc,it beyons i e d question. Hungary is the only socialist country that is able to export wheat. e relativelWar e y poo regards ra s both mineral resources and power supply. Wheat is only our renewable "convertible currency". But the arable land suitable for wheat growing is limited. Thus the raising of the grain yield per unit area is practically a form of "struggle for life". So we have to suffer the consequences: it is only a secondary question, or sometimes questioa t no allt na , whaf increasinprice o tth s i e e th g metric ton/ha yield. For this reason, all theoretical and practical possibilitie f improvinso productivite th g unir pe yt area, deeply circumstancesr interesou n i s tu : e.g. "non race- -specific" disease resistance researcr ,o hybrin ho d wheat, part of which is the semi-dwarf programme. known s eass i i produco s t yt A ,i e dwarf wheatsa t ,bu dwarf lin es talle whicit s goo a s ra ds hi sister linen si respect of its gene x environment interactions as well, is a really astonishing success. r "wheaOu t belt goos "ha d soil condition extremeln a d san y high fertilizer level, i.e. 4-500 kg active NPK/hectare. The height of our wheat cultivars varied from 85 to 125 cm. Near harvest there frequently occurred spells of strong winds and stora m destroye greatee dth nurserr firse parou th f tn to i y day Junef so extene .Th f lodginto r continenta ou n i g l climate is see Tabln i n . I e Altogether, only about 16% Of all genotypes studied were more or less lodging resistant, but scarcely more than one percent, 4 out of 354 showed distinct lodging resistance. The cultivars studied and their parent lines come from more than 6O countries > so these figures are perhaps characteristic conditionsr toou . wels Ii t l known thalodgine tth g tolerance relateo dt dwarfness and both the lodging and the height have a certain relatio yieldine th o nt g ability correlatione .Th s between these three characters resulting from the study of 120 representative population experimente parth s s a f to s mentioned are presente Tabln i d. II e e correlatioTh thin i n s experiment between heighd tan lodgin clears i g . Becaus yiele eth d doedepent sno heightn do , probabls i t i y usefu produco lt e dwarf cultivars, thouge hth loss of yield caused by severe lodging was seemingly not high.

INTRODUCTION Our project is one of the research projects supported IAEe bth yA whic specias hha l theoretica practicad lan l aims, inducing crossing_and introducin wels a gcomparins la d gan evaluating, semi-dwar dward fan f line cross sa s parents» These include well-known dwarf varieties, such as Norin 1O, Tom Thumb, Krasnodar 1, etc., as well as recently induced dwarf mutants.

52 MATERIA d METHODan L S To achieve our objective we used single Co gamma ray irradiations of dry seed conditions with 50OO and 15.000 rad, and made crossings /diallel p cross ,to r geneti fo / c analyses. The work :is being carried out along different lines of study. I/ Materials e greenhousgrowth n i n e under controlled conditions; a quicker approach with limited dimensions in experimentsC d an A,B . 2/ Materials grown in the nursery; taking longer but with a greater opportunit mutatior fo yF d nan C researcC , AA - h experiments. This procedure aim producint a s g practically useful dwarf cultivars, fropoine th m vie f t o breeding f wo , as well as valuable, genetically new dwarf sources, too. The experiments involve compilee ar d Tabln i d e IIId ,an divided int group4 o s: A and AA. Producing genetically new dwarf wheat forms by gamma rays B Crossing programme and diallel test of "old" dwarf lines p crosTo sC C analysi d an C s with Jubilejnay teste0 a5 f ro dwarf wheat lines. F Improvement of semi-dwarf productive cultivar candidates

RESULT DISCUSSIOd San N Experiment A and AA. Producing genetically new dwarf wheat forms by gamma rays Today most of the local and foreign wheats growing in Hungary are 80-10 talm havOd c lan relativelea y good standing ability. Among other seriesa cultivarf so growe sar n i n Hungary with a good quality grain yield, excellent winter hardines adaptatiod san n ability witt ,bu relativelha y long stem, 100-12 e.gm 0c . Jubilejnay Partizanka,thesd an 0 a5 e ar e preferentially grow poon no r harvese soilth s .mechas A ti - nized, the importance of evolving semi-dwarf versions of these cultivars is being stressed. In a part of our mutation program, these two cultivars, the Soviet Jubilejnaya 5O and a Jugoslav Parti- zanka, were treated with two doses: 5OOO and 15.0OO rad 6°Co gamma rays, in air dry seed conditions. Greenhouse work Two thousand. M3 plants of these varieties were selected for reduced height in the greenhouse /Experiment A-4/, in October, 1981. The percentag f dwarfo e s (shorter tha 5 cm. 4 ns rathe )wa r highn i , both cultivars 3.6-4.0% respectively /Table IV./. Progenies of all of these will be grown as ear-rows for evaluation and further selection in the nursery.

53 Th 2 selectioeM e nurserth n i ny /Exp. AA-3mads wa /e last August proportioe .Th f dwarfno s mucswa h less here /Tabl. eV/ nexe Th t generation wil plantee le nurseryb th n i dd ,an partly in the greenhouse, too, to select those dwarf mutants and to test them in a top cross and to obtain some information on their genetic background. Figur show1 e distributioe o sth tw heighe e th th f f tno o varieties witwithoud an h t gamma irradiatioratie Th o. 2 M n i n of average dwarfe selecteth th o f t so e d plant bettes i s r for both cultivars» The untreated Partizanka is shorter than the untreated Jubilejnaya and also its own treated M2 population. The variabilities of the untreated and treated populations were different. The effect of irradiation of winter hardiness Winter hardiness decreased significantly afte highera r dos f irradiationeo worts i t h.I considering tha 1980/8n i t 1 e fielth n di experiment botf o _ h M] cultivar e th s s exposeo dt 1500O R of 6°Co resulted in complete destruction during the winter. The untreated control and the M]_ treated with 5000 rathesf do e cultivars survived without e samdamagth en i e field. Treatment wit 15.0Oe , 5OO 0 hwel th s als d Oa s Olra a o resulted in survivals in the greenhouse without loss in winter. To study these results more carefully experimene ,th s twa repeated the following winter 1981/82 with exactly the same material. We realized again that the 15.OOO rad irradiation populatio_ M] mad plante e th th e f nso more susceptible th o et frost wintee .Th r loss less wa previou se th tha n i n s year, but barely half of the plants survived compared to the control, this_year o /Tabl,to e VI/.

Experiment B. Crossing programme and diallel tests of "old" dwarf lines Some of the identified and non-identified dwarf mutants, originating partly fro earlier mou r programme, partly from foreign varieties for which we lack genetic information, were studied in crosses. The diallel mating of these was e greenhouseth carrien i t dou . Becauswide th e f eo rang n ei the flowering time of the lines involved, the first set of hybrids was attained August 1981 and finished within February 1982 completA . t /withouese t reciprocal thesf /o e hybrids along with the parents was put into the experiment for the diallele analysis. The set of wheat cultivars studied was as follows : Bulgarian dwarf, Karcag M 522iA , Krasnoda putativ, C4 (Karlir1 v M e, 1) k apomictic Thumbm To d .,an crosp To Experimen s. CC analysi d an tC s with JubilejnayO a5 tester of dwarf wheat lines One hundred wheat lines, all shorter than 70 cm, were selected in 1980 froregular mou r nursery lines. Although their dwarfness was genetically not fully understood, their phenotypic yield factors were promising /Experiment CC/.

54 97 dwarfs were successfully crossed in 1981 in the greenhouse with the excellently adapted, but tall and unsuitable combiner. Jubilejnaya 5O as a tester /CC-2/. The hybrid seeds obtained were divideds growe wa th onct ^ na F n i e.e th Par f to greenhous 1981n i e . Afte greenhouse rth e harvest, F^ e ,th 2 populationF s along with their parental lines were planten i d e nurserautume th th n f lasni o y t year /Experimen. 3/ t The aim of this analysis is to find among the many lines and types those which combine welt lno wito testee d hth d ran destroy its favourable qenotypical characteristics. The majority of the dwarfing factors in the tested combinations proved recessive,with some exceptions /Experiment CC-4/. From the originally selected 97 lines^ 35 were more or less promising combiners. 3 of these proved partly dominant or the F, was phenotypically more similadware th fo rt parents , thae th n tester. Many were intermediate or recessive. Plant heights of e fouplant2 parentsF th r d f typicaso an I ,F l combinatione ar s show Figurn ni . e2 Because both parental lines of these combinations were nea o optimat r environment ou n i l , probabl w groune f a ypo hybride th s coul obtainede db , with phenotypes even neareo rt the optimal. We are planning to repeat this work with new parentals, too. First of all>within the framework of this IAEA research wor obtaio kt dwarw nne f form scrosp sucto sa h system will be studied. The new dwarfs obtained from A and AA experiments, will also be crossed with the Jubilejnaya 50 in the greenhouse at thif o sthd yeaeen Experiments/2 C- r d /C- an p crosl to se .Th FI will be planted also in the conditioned greenhouse for preliminary evaluation /Experiment C-3, C-4/. Experimen Improvemen. tF semi-dwara f to f productive cultivar candidate lase Iyear2 th n t1 duruo winteo tw stw md ran whea t cultivars have been produced by our group, all taller than 80 but less Beside. cm thaO sn10 this, many thousand semi-dware th f so f winter wheat lines have been tested. They were developed either by crossing, using the famous dwarf sources /Norins, Karcagi 522, Tom Thumb, Oleson, Minister Dwarf, etc./ or by induced mutation methods /!/. But all of these newly developed lines, as do the original sources, have at least one or more important unfavourable characters. These affec yiele tth d potential, adaptability, disease susceptibility, root systems, drought tolerance and winter hardiness, head-, seed- and stem characters, growing period, physiological equilibrum, etc. It seems that after 1O year's selection work our group recentl bees yha n abl mako et e some chang thisn i e . Recently a dwarf wheat was developed, which is the result of the last 3 years' work, a real breakthough in this field. This line is th158X eM , nicknamed "Mini Manö Englishn /i " : Mini-Manuel/, an up-to-date productiv s selectewa 8 e15 ddwarfX M fro e m.Th the combination of Arthur-Sava /Roussalka - NS 171.2 x F3O.74, crosseo Americans e on f so Yugoslaviano ,tw Bulgariae ,on d nan e RomaniaOn n line heighs .It 65-7o f t camm 0c e largely fro 171.2S N m . vers It y good yield potentia s inheritelwa d perhaps froe mth averagn o s i Sav Roussalkad e8 aan 15 30-35 X M %e .Th shorte r

55 and has a yield 15% higher than the best adapted variety, Jubilejnay whic, 50 a h cover wheae th s t f abouo acreag% 25 t n i e Hungary« Our data have shown that the MX 158 has a similar seed protein conten commerciao t l cultivars. Thuproteis sit n yield per unit area is outstanding. But its test weight /75.5 to 78.2/ and 1000 seed weigho 41g t winte d O /an /3 t r hardines e lowesar r than the control cultivar. Its good disease resistance to all 3 dominant fungi of our region mildew, stem- and leaf rust is inherited gooa fro s dm ha bakinArthur 8 15 gX .M quality,it s farinographic value bein whic, 2 gA h originated probably from the F30-74 Romanian line which is A^ quality. Becaus wintee th e r hardines seed san d charactere th f so MX 158 are only average, it is planned to improve these inducen a character f o dy mutatiowa y sb n technique. a Thi s si good step, becaus coult ei d produce some chang thesn i e e characters without alterin genetis git c backgrouno to d drastically. s registerewa 8 M15 X offician di l preliminary state tests this year.

REFERENCE

Viglâsi P., 1968. Short strowed mutants of Karcag 522 winter wheat induce gammy db a rays. Acta Agronomica 17:2O5.

56 TABLE I. LODGING PERCENTAGE OF DIFFERENT GROUPS OF WINTER WHEATS, Szeged, 1981/82.

Experiments No. of Lodging-resistant geno- Lodging population4 l al n si types % replications IWWPN 30 92 1 /Maris Madler COMECON /Socialist countries nursery/ 25 87 0 0 Hungarian cultivars and lines 179 76 2 /GK Boglâr, GK IldUco/ Hungarian "Blue Birds" 120 83 MinK /G i Man1 o /M.Manuel/

Total 354 X 84 4

TABL . CORRELATIONEII S BETWEEN DWARFNESS, LODGIND GAN YIELD IN WINTER WHEAT VARIETIES /n = 120/

Szeged, 1981/82

height x lodging r = 0.544 height x yield -O.09= r 7 lodgin yielgx d r = -0.239

57 TABLE III. COMPILATIO RESEARCE TH F NO H WORK CARRIED OUT 198 0198- 1

Year Month No. G REENHOUSE No. NURSERY of of exp. WORK exp. WORK

1980 10. A-l MLi plantinD SS n gi AA-1 M-, plantinD SS n gi F-l conplex dwarf populeition plantinw Ro r gEa 12. CC-1 line selecting for top cros testesO 5 wit j rhJb 1981 /fro~ 02M . m2 A-lA- / planting in SSD 04. CC-2 crossin crosp to sr gfo with Jbj 5O /A-2o 06M w .Ro /3 r planA- Ea n ti 08. l dialleB- l mating involving dward ol f mutants 1O. A-4 M3 /A-3/ selecting for /fro2 M AA-d m2an AA-1 I M / into height SSD P-2 plan yielt t1s d tesf to complex dwarfs /F-l/ 12. CC-3 Jbj 5O top cross exp. crosses'81.0e th 198f o 2 d en 02. 8l B- /B-l/ 04. O6. 08. B-2 planting of the "old" dwarf AA-3 selection of M-^ for varieties /B-l/ diallel dwarfness /from AA-2/ F-3 2nd yield test of complex dwarfness /see F-2/ 5 A- . 1O planting Mo /from AA-3/ AA-4 plant of M^j dwarfs /from an /A-44 dM w / Ro int r oEa A-4, AA-3w / Ro int r oEa C-l plant crosses of new dwarregisteo t f4 Mxl5f F- ro w 8d varieties /A-4, AA-3/ from F-l,2,3. 12. B-3 harvest and evaluatio ncrosp ofto s0 5 harves CC-j 4Jb t B-2 "old" diallel C-2 top cross mating /C-l/ 1983 02. C-3 top cross Fi planting C-2/ 04. 06. C-4 top cross /new dwarf varieties/ harvest, evaluation /C-3/ 08. - Report of the research and breeding work

58 TABL . PROPORTIOEIV DWARFF , GREENHOUSE3 NO M N I S , 1981

Untreated 5,00 d 15,000ra d 0ra Jubilejnaya 50 3,8% 3,6% 5,5% Partizanka 4,6% 3,7% 6,2%

TABL PROPORTIO. EV DWARFF NURSERY, 2 NO M N SI , 1982

Untreated 5,000 rad

Jubilejnaya 0,1% 0,1% Partizanka 0,3% 0,1%

EFFECE TH TABLGAMMF TO . EVI A IRRADIATIO SURVIVAN NO L RATES OF M! PLANTS. 1981/82, Szeged, in field condition Check 5OOO 15.00O rad Jubilejnaya 5O 1OO% 98% 48% Partizanka % 10O53 %% 98

59 plant frequency

30 -

20 -

height cm 31 36 41 46 51 56 61 66 71 76 81 86 91 96 101

FIGUR . E1 DISTRIBUTIO PLANF N0 T HEIGHT JUBILEJNAYF SO D AAN PARTIZANKA AND OF THEIR M3 SELECTED FOR SHORT CULM FOLLOWING SEED TREATMENT WITH 5.000 RAD GAMMA IRRADIATION

60 cm cm 90- d* 90 " cS1 80 - 80'

70- 70 - F 60. f ? X 60 - 1 50. 1 50 - çft 1 1 1 40- 1 40 - 1 l ! 11 i l I 'cm 40 50 60 70 80 90 40 50 60 70 80 9O

KDJ dw-NS88 50-TPR34j Jb x 6 0 GK618 x McNAIR 1782

cm cm F 90 - cf* 90~ l/" F2 I 80- 80- 1 ' 70 . 70- V 1 1 1 , 60 . 1 60- 1 1 $ 50- 1 50- i ' 1 40- i > 40 - ', i ! i M— -r • i i i i i i i 1 cm 40 50 60 70 80 90 0 9 0 8 0 7 0 6 0 5 4O RSK-NS171-2 RSK-RN12 x RNA3/ZG 2396

FIGUR . E2 INHERITANC SOMF O E2 F TYPICA D DWARFISF EAN O X LF N HI CROSS COMBINATIONS

61 THE EFFECT OF THE TOM THUMB DWARFING GENE ON GRAIN SIZE AND GRAIN NUMBER IN WHEAT (Triticum aestivum)

M.D. GALE, J.E. FLINTHAM Plant Breeding Institute, Cambridge, United Kingdom

Abstract

m ThumTo e b Th dwarfing gene, RhtS, likrelatee th e d genes RhtlRht2d an fro pleiotropis m ha NORI , 10 N c effect n indivso - idua yieldsr ea l d grai,an n protein concentrationsn A . experimen s conductetwa whicn i d h tiller numbe planr rpe d tan grain number per spike were restricted to ascertain whether reduced grain size and protein content are primary or secondary competitive effects in near-isogenic lines. The potential r graifo n growt s e identicashowb hwa t o t nrh RhtSn d i l an genotypes when grain set was restricted, indicating that the primary increaso effecgene t th s ei f to e spikelet fertility. Nitrogen accumulation within the grain was also affected by inter-grain competition but decreased nitrogen yields per plant indicated that reduced protein levels are, in part, a primary effect of the gene. Analysis of individual grain yields withi t spiken rh Rht3 d san showed tha e gentth e affected developmental 'dominance' relationships within the spike. 1. INTRODUCTION In wheat (Triticum aestivum), the three dwarfing genes, RhtlRht2d an fro mRht3d NORIan 0 fro1 Nm Thumb mTo , have been associatee showb o nt d wit n increasea h d numbe f smallero r varietan i r grainea lr comparisonspe s , e.g. Borlaug {!}, Clements et al. {2} and in better genetically defined material {3}. In experiments with random lines produced from single hybrids, groups of Rht homozygotes were compared with rht lines in similar average genetic backgrounds to provide results on ear yield components such as those shown in Table I {4}addition I . n dwarf lines exhibi treducea d grain nitrogen Table I. The relative effects of Rhtl, Rht2 and Rht3 on ear yield components. rht Rhtl Rht2 RhtS Plant height 95 cm -15.8 -14.4 -43.3 0 5 Grai+16.13n no./ea; r+20.7 % +38.8% 4.1- 4.8- %% g 4 -13.85. % 100 grai t nw Note. Measurements made on spaced plants of F^ random lines, homozygou tale th l r comparesfo d witdware th h f allele, derived from hybrids of Maris Huntsman (rht) with Sdl (Rhtl), Bounty (Rht2) and Minister Dwar meane fvaluet th (Rht3). rh s e e ovesar Th r all three tall groups, in all cases the dwarfs differed significantly from their respective tall controls {fro. m4} 63 level, although not always reduced nitrogen yield on a per unit cropped area basis {3} purpose experie .Th th f eo - ment describe destabliso t her s ewa h whethe effecte rth f so these dwarfing genes on grain size and protein content are primary effects, which should therefore be considered by the breeder in choosing a suitable genetic dwarfing system for his programme entirelr ,o y secondary competitive effects, caused e increasebth y d fertility withi spikee th n . e threTh e gene e closelsar y related genetically, Rhtld an Eht2 being homoeoalleles on chromosomes 4A and 4D {5} and RhtS bein n alternativa g e Rhtle allelth t locua e s {6> threl .Al e alleles are associated with gibberellin (GA) insensitivity and have qualitatively similar pleiotropic effects. However Rht3 is quantitatively more extreme in all respects and therefore provide n ideaa s l test syste r analysi me pleiotropifo th f o s c effects on development of these genes. e techniquTh f artifialleo y reducing grain numbeo rt investigate grain growth potentia wels i l l established {7,8,9} and is exploited here to observe the effects, on grain size and nitrogen content, of progressively decreasing inter- grain competition. . 2 GENOTYPE METHODD SAN S 2.1. Near-isogenic lines t linerh Rhts d s an wer e extracte intermediatn a t da e stage of a backcrossing programme to develop isogenic lines. The winter variety Minister Dwarf was the Eht3 donor and was hybridised and backcrossed three times to the tall spring variety April Bearded RhtZ/rhte Th . hétérozygotes thus obtained obtaio wert d e nfe the l botnse h type homozygotef so s which were then sel fed once more to provide the experimental lines. This procedure was carried out in duplicate to provide a tes backgrounf to d genetic homogeneit expectes wa d o an yt d provide genotypes with homozygous April Beardet a d s ale l le 15/16th e loct linketh no i f so d with RhtS. 2.2. Experimental methods Thirty-two plants of each genotype (16 of each duplicate), excluding guards, were grown in two identical controlled environment cabinets. Environmental condition r growtfo s h wern ea 18 h photoperiod at 150 W m"2 at 15°C and 5 h dark at 10°C. Relative humidit maintaines cen r wated ywa pe tan 0 r8 t a d supplied continuousl y capillaryb y wick o individuast l pots containing 0.91 John compost2 Inné . sNo . In each cabinet, eight plants (four of each duplicate) were assigne randot a d eaco t mfouf o h r treatments control, 1 : , allowe t graitilleo t se d nd ran freely partiall, 2 ; y degrained, all florets removed three days after anthesis except the two basal florets in the central 12 spike!ets of each spike; 3, partially detillered, all shoots except the first two removed as they appeared , combine4 ; d degrainin detilleringd an g , leaving a maximum of 48 grains per plant. 64 At maturity all spikes were harvested and freeze dried to a constant 6 per cent moisture before assessing either ear yield component r individuao s l grain weight t positiona s s within the spike. Nitrogen contents were measured using the micro-Kjeldahl method described by Starr and Smith {10K

3. RESULTS AND DISCUSSION In comparin t genotypesg rh Rhts d an e contro,th l plants showed similar qualitative difference o thosst e found under field conditions with random lines grown as spaced plants or small drilled plots (11}. Rhts plants had more tillers (9.7 7.25v 5 s.e.d. 0.52 mord )an e smaller grains thae th n comparable tall rht plants (Table II). No differences were found in overall yield per plant.

3.1. Mean grain size As expected, treatments 2, 3 and 4 progressively decreased yields and grain number and increased mean grain size (Table II) showing that grain size is restricted by competition both between tiller d betweean s n e samgrainth e n o s spike. However, this effect is greatest within the ear because, although yields were decreased more by treatment 3, the improvemene th markegraio n n s i ti t s na dno siz s ewa degrained plants treatmenn I . , althougt4 h grain numbers were

Table II. The mean effects of degraining and detiHering treatments on yield and its components in tall and dwarf near-isogenic lines. Tall, rht Dwarf, pht3

Grai. no n Yield Grain Grai. no n Yield Grain Treatment /plant /pi ant(g) wt (mg) /plant /plant(g) wt(mg)

1 3 ± 2 8 32 2 t 10. 0 5 1. 37.16 227 .± 1. 0Contro t l 1 10.1. 33.4 9t 1. 8+ 6 1 ± 5 20 9 8 0. 47. 1. ± 3t 7 7. 4 1 i 3 Degraine. 2 16 d 8.9 i 0.8 43.6 ± 1.5 1 1 ± 4 17 6 4 42.0. 1. 4 74 2 6. 3 .9 ± Detlllere 5 14 d 6.9 ± 0.5 39.6 t 1.4 2 ± 2 4 1 2 54.0. 2. t 5i 5 2. 2 t 5 4 Combine. 4 d 1 57.3 0. 2. 1. ± 4 7 i

Note l values confidencAl X : 95 ,4 e limits meane ,ar f eigho s t plants.

not quite equal because of some sterility in the basal florets, grain size was at least equalised indicating that grain growth potential is not restricted in the dwarfs. These result e consistensar t with thos f Radlseo d an y Thorne {9} who showed that degraining had a greater effect in the Rht2 variety Hobbit compared with the tall variety Maris Huntsman. Percentage increase her s greate Rhtse ewa th n ri plants becaus e graineth s were smalle e controe th th d n i ran l

65 same in treatment 4. Brocklehurst {12} obtained similar results d attribute,an greatess hi d t response o degrainint s g to increased numbers of endosperm cells. In this experiment, thosn ai s y Radleb e d Thornean y ,e thith e sb appearo t t no s case becaus e graith e n size difference e controlth n i s s only became apparen 0 day5 t s post anthesis {13}, long after cell division in the endosperm has ceased.

-3.0

PERCENTAGE NITROGEN uo N -2.0 60- k ai S o» s -1.0 * 50-| e "5 GRAIN WEIGHT e

40-

I 100 200 300 M« an grain number p«r plant e effecTh Figur f artificall to . 1 e y reducing grain number r planpe n graio t n siz d graiean n nitrogen level in tall and dwarf near-isogenic lines of wheat.

Note. RhtS plants (•»•), vht (o,a). Treatments; 1, Control, DegrainedZ ,Detillered3 Combined,4 meae Th n. grain weights are those of the two basal florets of the 12 central spikelets only, grain nitrogen being estimate e samth en i dgrains . Each point represent meae f eighth so n t plants.

66 e lineaTh r relationship between grain size (the meanf o s grain n basa i sd secon an l d florete centrath n i sl twelve spikelets d grai)an n numbe n Figuri r 1 indicatee s tha e initiath t l difference between the genotypes in the control plants can be entirely explained in terms of within-plant competition which became limiting in the RhtZ genotypes late in grain development. 3.2. Grain nitrogen content e relationshiTh p between grain nitrogen percentagd an e grain number is also shown in Figure 1. Clearly, since the removal of competing grains increased nitrogen content, com- petitio s likeli n o account ye differenc th r muc fo tf o h e between RhtZ (1.20%(1.40%t rh d )an , s.e.d. 0.04) genotypes. However e non-linearit,th e relationshipth f o y s indicates tha t leasa t e otheon t r facto s involvedi r . In addition, however, it appears that there is an effect of RhtZ unrelated to intra-plant competition since nitrogen yield per plant is decreased in the dwarfs both in controls (130. 7v 148. 0s.e.dg m . 0.21 treatmend an ) t4 (66. 570.v 3 s.e.d. 0.21). This may be due directly to the effect of RhtZ n plano t size than e ,dwarfi th t s hav a esmalle r nitrogen source than the tails. 3.3. Spike conformation The degraining experiment can provide information on the effect f increaseso e th dn o fertilit t dwarfe no th t n bu si y initia l e increascausth f eo grain i e n number. Figur show2 e s the origins of grain yield within the spike in Rhts and rht lines. This data was obtained from spikes in treatment 3 in rht3 Rht3

Spikeiet Number (basal-»distal) Figure 2. Hi thin-spike yield conformation in tall and dwarf near-isogenic lines. Note. Mean yields were obtained fro ear6 r mgenotyp1 pe s r efo basal (o,»), second (A,A), third (a,«), fourth (0,4highed an ) r order (v,v) florets. 67 yieldr ea whic e sth hwer t confoundeeno d with differencen si shoot number per plant. Two differences between the genotypes are clear. Within spike!ets e dwarf th e basan th i s, l grain e e smallear sth d an r higher order florets contribute more yield than in rht plants. Thi demonstrates i s d clearle thirth dy b y grains whice ar h smaller than the two basal grains in the tails and the largest in the dwarfs, just as was demonstrated by Radley {14} in a varietal comparison betwee Rhtln na carrie a tall d A ran . similar differenc apparens ei t withi e spikwholea th n s n ea I . rht plants grain yield drops off rapidly above spike!et 15, while in the RhtZ plants yield loss in this region of the spike is more gradual. In addition the dwarfs have, on average, more on e fertile distal spike!et thae tailsth n . Both these effects, alon e spik th alond g e spike!ean e th g t indicate a similar shift in 'dominance1. The source of this mora n i e e synchronouli shif y tma s anthesis within spikelets and along the spike in dwarfs {Radley, pers. comm.}. In this way the grains in higher order florets and at the top of ears will be more competitive than if they had started growth a few days behind. Ther insufficiens ei t informatio o speculatt n e th n eo underlying mechanism involved, but it seems possible that the origi e relateb hormonas y i n o othema t d d ran l shiftn i s apical dominance associated with the NORIN 10 and Tom Thumb dwarfing genes such as the unusual effects of applied GA on tiller production describe Galy b Marshald ean l {15}.

. CONCLUSION4 S 1. The dwarfing gene Rhts is pleiotropically associated with increased grain set within the ear. The gene increases the fertilit f distayo l florets withi e spikele e relath nth -d tan tive productivity of upper spikelets within the ear. 2. The associated reduction in mean grain size is entirely attributable to inter-grain competition. 3. The associated reduction in grain nitrogen content is only partially attributable to competitive effects, and nitrogen yield per plant is reduced by the gene. e genetiTh . c4 relationships betwee NORIe nth 0 RhtZ1 Nd an semi-dwarfing genes indicate that qualitatively similar effects can be found for these two economically more important alleles.

Acknowledgements This work was carried out as part of a postgraduate research project and will be reported more fully elsewhere. JEF gratefully acknowledges the support of the Home Grown Cereals Authority durin studentships hi g .

68 . 5 REFERENCES {1} BORLAUG, N.E. Wheat breeding and its impact on world food supply. Proceedings 3rd International Wheat Genetics Symposium (1970) 1. {2} CLEMENTS, R.J., CROSS, R.J., SANDERS, P. Effect of sowing rate on the growth and yield of standard and semi-dwarf wheat cultivars w ZealanNe . d Journa f Experimentao l l Agriculture (1974) 139. } GALE{3 , M.D effecte Norie .Th th dwarfin0 1 nf so g genen o s yield in wheat. Proceedings 5th International Wheat Genetics Symposium, Delhi, 1978 (1979) 978. {4} GALE, M.D. The role and potential of dwarfing genes in wheat. Proceedings of the International Symposium on w GeneticaNe l Approache Croo t s p Improvement. ,ed K.A. Siddiqui (1982 press)n )(i . } McVITTIE{5 , J.A., GALE, M.D., MARSHALL, 6.A., WESTCOTT. ,B The intrachromosomal mapping of the Norin 10 and Tom Thumb dwarfing genes. Heredit 0 (1978y4 . )67 {6} GALE, M.D., MARSHALL, G.A. The chromosomal location of Gcdl and Rhtl, genes for gibberellin insensitivity and semi-dwarfism, in a derivative of Norin 10 wheat. Heredity 37 (1976) 283. {7} BINGHAM, J. Investigations on the physiology of yield in winter wheat y compariso,b f varietieo n y b d an s artificial variatio grain i n n numbe r earpe r . Journa Agriculturaf o l l Science, Cambridg 8 (1970e6 ) 411. {8} RADLEY, M.E. Factors affecting grain enlargement in wheat. Journa Experimentaf o l l Botan 9 (19782 y ) 919. {9} RADLEY, M.E., THORNE, G.N. Effects of decreasing the number of grains in ears of cvs Hobbit and Maris Huntsman winter wheat. Annals of Applied Biology 98 (1981) 149. (10) STARR, C., SMITH, D.B. A semi-micro dry-block and automated analyser technique suitabl r determininfo e g protein nitrogen in plant material. Journal of Agricultural Science, Cambridg 1 (1978e9 ) 639. {11} FLINTHAM, J.E., GALE ,Thumm M.DTo e b .Th dwarfin g gene, Shts, wheatn i . EffectII . n heightso , yield an d grain quality. Theoretica Applied an l d Genetics (1982) (in preparation). ) BROCKLEHURST02 , P.A. Factors controlling grain weighn i t wheat. Nature 266 (1977) 248. {13} FLINTHAM, J.E. The physiological role and plant breeding potential of the Tom Thumb dwarfing gene in wheat. PhD Thesis, University of Cambridge (1981) 181. {14} RADLEY, M. The effect on wheat grain growth of the removal or ABA treatment of glumes or lemmas. Journa Experimentaf o l l Botan (19812 3 y ) 129. {15} GALE, M.D., MARSHALL, G.A. Insensitivit gibberellio t y n in dwarf wheat. Annal Botanf so (19737 y3 ) 729.

69 THE EFFECT OF THE NORIN 10 DWARFING GENE, Rht2, ON YIELD-BIOMASS RELATIONSHIPS IN WHEAT (Triticum aestivum)

J.W. SNAPE, B.B. PARKER Plant Breeding Institute, Cambridge, United Kingdom Abstract The genetical relationship between total above ground plan y weightdr t (biomass yield ) an whea n i ds bee tha n examine crosa n i ds betwee o Europeatw n n winter varieties using random F6 lines homozygous for Rht2 and its alternative 'tall1 allele, rht2. Withi Hhtze rht2d th nan genotype groups ther s sigewa - nificant genetical variation for biomass and all productivity components, showing that ther s heritablewa e variatior fo n these characters independent of the dwarfing locus. Further, withi e groupth n s strona ther s ewa g positive correlation between productivity components and biomass indicating the importance of biomass variation in determining yield variation. However significano n ther s ewa t difference betwee genoe th n - type groups for grain yield although Rht2 reduced vegetative yield d thereforsan e cause n increasa d harvesn i e t index. Consequently Rht2 would appear to reduce "nonproductive" rather than "productive" components of biomass. The implica- tions of the results for biomass and yield selection in breeding programme discussede sar .

1. INTRODUCTION Recent experiment barlen i } d hav {2 yan whean e i s} t{1 suggested that genetical improvements in yield brought about y planb tthiK U breedin se centurth n i g y have e ariseth y nb increas e proportioth n ei f grai no weighy dr n t relativo t e total above groun weighy dr d t (biomass). Essentially, improvement has been achieved by increasing harvest index. generae Th l consequenc f thieo s progressio bees nha n that modern varietie e highesar r yielding with shorter strat wbu have littlo increasn r eo overaln ei l biomass over their forebears. However, increases in harvest index have a physiological limit. In wheat, for example, Austin et al. {1} cal- culat limiea 60%f to . They have proposed, therefore, that future genetical gains in yield will depend on detecting and exploiting genetical variatio r biomasnfo s production. In wheat, recent increase harvesn i s t index have been greatly influenced by the introduction of major dwarfing genes into breeding programmes, particularly the Norin 10 genes, Rhtl and Rht2. In consequence it is important to determin effecte eth f thesso e gene yield/biomasn so s relationship thao s t strategie r increasesfo d biomass production, whilst maintaining semidwarf habitformulatede b n ,ca .

71 e presenTh t paper report resulte experimenn sth a f o s t forming par f biomasto s investigation e Planth t a s Breeding Institute. This was carried out to examine the genetical relationship between Rht2d productivitan y componenta n i s cross betwee o higtw n h yielding European winter wheats.

2. MATERIALS AND METHODS The cross between the varieties Sava and Hobbit 'S' was chose r investigationfo n . successfua Sav s i a l Yugoslavian variety which, unde K conditionsrU semidwars ,i staturen fi , earl d witan y h high tillering capacity.a s Hobbii ' 'S t sister a successfulin f o e l serie f higso h yielding, Rht2, semi dwarfs developed at the Plant Breeding Institute.

Random F6 lines between these varieties were developed by single seed descent (SSD). Initially three generations of SSD were practised from F2 to F^. Subsequently, F5 plants were grown under spaced plant conditions to provide Fg families for the present investigation. Each F6 line was the product of a separate F2 plant.

The individua 6 lineF l s were characterise r seedlinfo d g GA sensitivity to identify homozygous Rht2 (dwarf) and rht2 (tall) genotypes {3}. Twenty two of each genotype were chosen for the present investigation. These were grown in a randomised block experiment consisting of five replications. In each block, each lins representewa e singla y b d e plo, tof 11 plants with plants sown 10 cm apart within plots and plots spaceapartm c 0 3 d. During maturityt growta d han ,ranga f eo agronomic character s measureswa eacn o d h individual plot. At harvest, plots were cut at ground level and sheaf weights measured. Four random leading tillers were then take r detailefo n d measurement f individuaso l tiller productivity components and the remainder threshed to provide plot grain yield and vegetative yield data. All data were converted to individual plant or single tiller measurements for analysis.

3. RESULTS AND DISCUSSION 3.1. Yield/biomass relationships within Rht2rht2d an groups. o examinT geneticae eth l variatio r planfo n t productivity components an analysis of variation within and between Rht2 and rht2 genotype groups was carried out (Table I).

72 Tabl . eI Analysi f varianco s f variatioeo n betwee withid nan n rhtRhtd 2an 2 groups.

Mean Squares Item df Biomass/ Height Ear No./ Grain Yield/ Vegetative Harvest plant (g) (cm) plant plan) (g t Yield/ Index/ plant(g) plant

Between groups 1 773.4 11105.8*** 0.85 2.2 965.6 732.7*** Within groups 42 1093.2*** 419.6*** 13.12*** 207.7*** 392.9*** 58.9***

Between Rht2 lines 21 1145.7*** 329.0*** 14.63*** 231.4*** 371.7*** 58.1*** Between rht2 lines 21 1040.8*** 510.2*** 11.62*** 184.0*** 414.0*** 59.8*** Error 172 55.6 7.9 1.54 19.4 16.6 5.2

Significance level * <0.00** : 1

Table II. Correlations between biomass and productivity components within Rht2 and rht2 groups Productivity Component Genotypes Plant Ear No./ Grain Vegetative Harvest Whole Grain yield/ height plant yield/ yield/ Index/ tiller tiller plant plant plant weight

Rht2 0.74* 0.77*** 0.97*** 0.92*** -0.08 0.78*** 0.64** rht2 0.51*** 0.59** 0.92*** 0.98*** -0.36 0.78*** 0.64**

Significance levels: 0.05-0.0= * 1 ** = 0.01-0.001 *** = <0.001 Considering differences withi genotype th n e groups first, ther s significanewa t genetica le product th variatio l al -r fo n ivity characters measured. This indicates tha thin i t s cross there are genes segregating for whole plant biomass and its components which are independent of the variation at the Nht2/rht2 locus. Biomass is therefore amenable to selection in the same way as other productivity characters. Examination of the relationship between plant biomass and productivity components within the Rht2 and rht2 groups (Table II)shows tha componentl tal e highlsar y correlated with whole plant biomass except harvest index/plant. The correlations between biomas d graian s n yield d biomas,an d vegan s - tative yield are expected to be large because of the element of autocorrelation. However there were also strong correlations between grain yield vegetativd an s e yield 0.9f o sd 2an 0.83 for the Rht2 and rht2 lines, respectively. Hence larger plants have higher grain yields and also vegetative yields, and harvest index can remain constant over a range of yield values. This result support e ideth sa that selectior fo n increased biomass will increase yield potential. However selectio r higfo n h harvest index with high yiel y limima d t the potential of genotypes as parents for further yield advance y selectinb s g against gene r higsfo h biomass which have potential for yield improvement. e stronTh g correlation between plant heigh yield an t d that has been commonly found in segregating generations of crossecorrelatioe th probabls i whean o si t } e {4 tf ydu no both of these characters with whole plant biomass. This gives further support to the idea that selection for "tall dwarfs" should improve yield {4,5}. 3.2 Differences between Rht2 and rht2 genotypes. meae Th n performanc Rht2e rht2d th an f eo genotype r sfo whole plant and single tiller characters is shown in Table III. Firstly expecteds ,a primare ,th y effeco t Rht2f to s i reduce plant height thin ,i s averagn crosa y sb f 14.eo . 2cm However this doe t affecsno t yielding abilit d thero n an y s ei significant difference betwee genotype nth e group r graisfo n yield/plan r graito n yield/tiller. agreemenn i Thi s i s t with other studieeffece th Rht2f f } whertso o dwarfin{5 e eth g gene has been neutrae foun b havo t o dt er o lonl smalya l positive effect on yielding ability. This is because a pleiotropic effec o increasRht2t f t o s i numbe e th e grains/eaf ro t rbu this is balanced by a corresponding decrease in grain size. Secondly, there is a highly significant increase in both whole plan d singltan e tiller harvest indiceKht2e th n i sgeno - types. This indicates that Rht2 causes a reduction in vegetative yields and therefore of overall biomass, though the reductio wholf no e plant biomass doereact sno h statistical significance. This suggests tha effece tth Rht2f t o bion o - mas independens si strone th f gto correlation between biomass and yield found within the genotype groups. Presumably the biomass reduction is a consequence of a reduced amount of

74 Table III. Mean performanc f Rht eo d rht 2an 2 groups.

(a) Whole plant characters Biomass/ grain yield/ vegetative yield/ HI/ Height Ear No./ Genotype pi ant (g) plant(g) plant(g) plant (cm) plant Rht2 48.52 22.79 25.65 47.11 87.6 9.77 rht2 52.27 22.99 29.84 43.46 101.8 9.65 Significance of difference NS NS NS *** *** NS

(b) Single tiller measurements

Whole tiller grain yield/ vegetative yield/ HI/ grai0 5 n Grain Number/ Genotype weigh) t(g tiller(g) tiller(g) tiller weight(g) ear Rht2 5.783.15 2.62 54.38 2.35 67.2 rht2 6.493.40 3.09 52.37 2.63 64.7 Significance of differenc* e NS * * * *

Significance levels S N 0.0: 5 * = 0.05-0.01 *** < 0.001 straw since ear number is unchanged. It would appear therefore thae strath t w biomass component either doet conno s - tribute a great deal to grain filling or that Rht2 conditions a higher production rat f photosynthateo e which compensates reducea r fo d amoun f producinto g tissue. Physiological studie f carboo s n translocation during grain filling would suggest that the former is more likely since the major con- tributors of carbon for grain filling are the flag leaf and the ear itself {6}.

3.3. Model r biomasfo s s selection The effect of the Rht2/rht2 locus on the yield/biomass relationship thin i s s cross suggests that biomase b n ca s partitioned into "productive nonproductived an " " components where only the productive element contributes to grain fill- d inthereforan g e yield (Figure l,a) n thiO . s model Rht2

Yield/Biomass Models

Grain Productive Yield Biomass

Nonproductive

Productive Grain High Yield Biomass Genotype

Nonproductive

Grain Productive High Yield Biomass Genotype Nonproductive

Figur . e1 Relationship s between biomass componentd san grain yield.

76 reduces the nonproductive component and consequently harvest index increases without a change in average yield. Thus when genotypes with high biomass are detected it may be necessary to determine if the genetical variation present for biomass will contribute to the productive rather than the nonproductive component. Only if genotypes contribute to an increase in productive biomass will the e usefub y s parenta l o t s produce yield increases (Figuree basie l,b)th th f o sn .O present results selectio r higfo n h biomass genotypes which have large amount t contribut no f straso y ma w yielo t e d increases because little or no increase in productive biomass is obtained (Figure l,c). Given that useful high biomass genotype e identib n ca s- fied a strategy for increased biomass selection when Rht2 e dwarfinisth beinx fi g o t genuse earls n i i ed y generations and selec r "largtfo e dwarfs procedure th - " e sugnsstey db Gale and Law {3} in selecting "tall dwarfs". This strategy should increase yield whilst maintainin a higg h harvest index and should also conserve genetic variatio r planfo n t biomass.

4. REFERENCES

{1} AUSTIN, R.B., BINGHAM, J.t BLACKWELL, R.D., EVANS, L.T., FORD, M.A., MORGAN, C.L., TAYLOR . Geneti,M c improvement winten i s r wheat yields since 190 associated 0an d physiological changes, Journal of Agricultural Science, Cambridge 94 (1980) 675. {2} RIGGS, T.J., HANSON, P.R., START, N.D., MILES, D.M., MORGAN, C.L., FORD, M.A., Compariso sprinf o n g barley varieties grown in England and Wales between 1880 and 1980, Journal of Agricultural Science, Cambridge 97 (1981) 599. {3} GALE, M.D., LAW, C.N., The identification and exploitatio f Norino semi-dwarfin0 1 n g genes, Plant Breeding Institute Cambridge Annual Report 1976 (1977) 21. } LAW{4 , C.N., SNAPE, J.W., WORLAND, A.J. geneticae ,Th l relationship between height and yield in wheat, Heredity 40 (1978) 133. {5} GALE, M.D., The effects of Norin 10 dwarfing genes on yield, Proceedings Fifth International Wheat Genetics Symposium Delhiw ,Ne , 1978 (1979) 978. {6} AUSTIN, R.B., JONES, H.G., The physiology of wheat, Plant Breeding Institute Cambridge Annual Report 1974 (1975). ,20

77 INHERITANC CULF EO M HEIGH GRAID TAN N YIELD IN DURUM WHEAT*

K. FILEV Institut Geneticsf eo , Sofia, Bulgaria

Abstract

Results from a study of GA sensitive and GA insensitive durum wheat mutants and cultivars in relation with their culm height and 1000 grain weigh e presentedar t . With increasing culm height A responsG e th , e also increased. A positive correlation between plant height and GA response was found. Crosses were made between durum wheats and the F and F_ progenies were analysed .A differen t inheritanc d segregatioan . F ~ F n i en i n was obtained in crosses of a semidwarf, GA insensitive [l] line with GA sensitiv ) line(S e s differin heightn i g , medium (93.2cm d tal)an l (133.5cm). Ireciprocaa n l cross, semidwar witI - fsemidware h th mediu , S - mf typs wa e dominant in F1, suggesting that their semidwarfing genes were not allelic. Whesemidware d talth nwerS an - le I crosse- f n intermediata d e inheritance in F.. was observed. In the F- generation from crosses semidwarf - I with medium witS - h semidwar phenotypia , I - f c dihybred segregation 9:3:3; s observed1wa . In crosses gemidwarf - I with tall - S different variation curves were obtained. Semidwarfs with high productivity were a facobserve , tF» n i d indicating that lodging resistant lines with high yields coul e selectedb d .

Introduction

e nee o Th increast d e durum wheat productivit o develot d an yp lodging-, disease- and cold-resistant cultivars requires genetic investigations aimin develoo t g w formpne s which coul e use b dn cross-breeding i d . Experimental mutagenesis research bot Bulgarin i h a [l,2othen i d r]an countries [3,4], has yielded several durum wheat mutants and cultivars s importani ant i d t that thee studiedar y e mutant.Th s represent valuable stocks useful in breeding programmes for the development of new cultivars [5~\. Breeding for lodging resistant cultivars requires investigations concerning the nature of the mutants and cultivars produced so far, both for their GA sensitivity and for their reduced height genes. Strampelli's Akagomoughi wheat derivative A sensitivG e ar s] whil[6 e e those developed later by Valleg Zitelld whicn i an gene a ] th he [7 i Nori 0 (Daruma1 n s )wa introduced are GA insensitive. The genetic diversity created in durum wheat is considerable. Mutants obtained and cultivars have been distinguished A sensitivityG bot n heighn i i h d an t . However e interrelatioth , f o n gibberellin sensitivit d semidwarfinan y n durut clarifiedi g ye mt wheano s i .t [8,9]. e presenth f o t m investigationai e Th , therefore o studt e s th y ,wa GA response of some mutants and cultivars in relation to their height and 1000 grain weight, and the inheritance of plant height and yield in crosses between semidwarf and medium height plant, and semidwarf and tall plants.

* Research was supported by IAEA under Research Contract No. 2688/RB.

79 Material d methodan s s

Eight mutant line d fouan s r cultivar f duruo s m wheat were analyser fo d A responseG . Seedlings height measurement A responsG d an s e data were collected after growing seedlings in distilled water at 10 ppm GA„ solution for 7 days e dard theith nan k 7 dayn s under light accordin methoe th f Myhilo o t dg d an l Konzak [lO]. In addition, we made a parallel supplementary investigation placin e germinatinth g g seed s7 days onlr ,fo y e dareithe r th undeo kn i rr light gibberellin and in water as a control. Crosses were made between durum wheat a cultivaline d an s f o r winter habit differin A n heighresponseG i g d an t e firs.Th t lins wa e 15/4-2 semidwarf -I (71.3cm) mutant, induced at the Institute of Genetics, Sofia, using gamma radiatio , see F ncombination i d n /788 x(Montanar Val)/x i . Second Ambra, mediu S (93.2cm- m ) mutan s inducewa t d using gametophyte irradiation of N 788 and followed by crossing with Castelporziano . 1522no . an,cv dtalS (135.5cm) — l - plantF e .th s grown were harvested and each spike progeny was sown separately in 4 m rows spaced 30cm. The parents were sown in two replication of 2 rows. The highest tiller of F and F_ plants was measured. Segregation for plant height in F„ was recorded. Fifty to sixty plants of each parent were measured. Segregation for plant height in F„ was recorded. Fifty to sixty plants of each parent were measured.-The individual plants were threshed separately and their grain yiel s recordedwa d .

Results and discussion

Results of gibberellin treatments at different illumination and duration of the 12 durum wheat mutants and cultivars having different plant height are presented in Table I. Some of these cultivars, as Valnova is A insensitiveG , while Castelporzian A sensitiveG s i o e foun.W d also that mutants (15/4- d Zeverjana2an ) with short culd largan m e grainA G e sar insensitive. The three comparative trials indicated that the greatest elongation of the plants is produced in the dark, a fact also observed by other authors [8] n cas.plante I th egrowe ar s n under light elongatioe th , n e wateth n ri contro s lesi l s whilee gibberellith n i , n solutios i t i n considerable. Plant elongatio e dar mucth s i kn hi n more pronounced, botn i h the water control and in the gibberellin solution. Therefore, the differences between the treatments are smaller. GA insensitivity is evident both in the dark and in the light. With increased culm height, the GA response increased also e foun.W positiva d e correlation between plant height, and GA response: for the treatments under light r=0.89^* for the treatments in the dark r=0.83** and for the treatments in the dark and under light for day4 1 s r=0.81**. Results presente Tabln i d provI e e tha n investigatioa t n lastin day7 g quits i s e sufficien asseso t A sensitivitysG . n importanA t observation whic he presen notee oughth b n o i t dt investigatio s thai n A e groutinsensitive G th botth f o pn n i hi d an e A grousensitivG f o p e plants, considerable variation existed regarding their GA response. Lines were observed, suc s 15/4-9a h , which occupie n intermediarsa y positio d coulan n e describedb s serai-sensitive.[MS]a d . These differences give e presumtiogroundth r fo s n that crossing cultivars with varying levels of GA insensitivity and GA sensitivity may lead to a different genetic performance. e chosW e froe stockth m s analysed A insensitivG e ,th e semidwarf mutant 15/4-2 A sensitivG e ,th e Ambra medium planA G e t th size d an s sensitive cv. No 1522, a typical tall variety, and crosses were made among them.

insensitiveA G I- sensitivA G - S ; e 80 Results concerning the mean culm height of the parents and the mean F plant height are presented in Table II. The variation coefficient of f 15/4-o cul F m 2Ambrx e heighd Ambrth an a n x 15/4-ai t a shows that the variatio s slighti n . Greater plant height variatio s observei ne th n i d F of the semidwarf 15/4-2 x the tall cv.No 1522. In this combination, the culm height of F. is intermediary to the parents. These results indicate that considerable difference e observear s F dependinn i d n whetheo g r thA sensitivG e e paren s mediui t n heighi m r typicallo t e y th tall n I . first case patterth e f inheritanco n e with semidwarfness dominans wa t observed, while in the second an intermediate inheritance of culm height was found in F.. . Measurement culthe m of sheighcros plantF~ the of stin s 15/4-2, (semidwar Ambrx ) I a presentee - f(mediu ar . 4 ) S d Fign - mi dan 1 . e phenotypiTh c segregation rati f planto o e expecte s closth i s o t e d ratio of 9:3:3:1. The chi-square analysis gave a good fit for a segregation = 0. 204/0.95 < P^ 0.99) . A similar picture is observed in the F„ segregatio crose th sf o nAmbr a (mediux 15/4- ) S 2- m (semidwar) I - f (Fig.2 and %). The phenotypic segregation ratio of plants is close to the expected ratio of 9:3:3:1. The chi-square analysis shows for segregation = 3.866 (0.2 P 00.5 . Thes0) e results shopresence o indépendantlth w tw f o e y segregating gene pairs 6 presen. d Fig measuremente an th t3 . f culo s m height in F„ plants from the cross 15/4-2 (semidwarf - I) x cv. No 1522 (tall - S). The segregation of the 259 F_ plants proves that in this cross a greater rang n culi e m heigh s foundi t . variatioThe n curvdemonstrateF~ of e s botvariatiothe h to due n environmental condition e variatio th o geneti t d e an s du nc causess a , e approximatth wel s a l e numbe f geneo r s controllin e giveth g n characters. e e variatiographTh th f o s n curves presente, dP« sho, heighe P th w f o t F. and F~ and give information concerning the mode of inheritance when parents differing in height and GA sensitivity are used in the crosses. The variation curves of the cross 15/4-2(semidwarf -I) x Ambra (medium - S) s evidene showi ar t n FigI i nvariatio. t. F. 4 . tha e th t n curve almost coincides with that of P., which gives grounds for the presumption that the inheritance f semidwaro f culm heigh s dominanti t . a cleaThi s i sr indication that the two semidwarfing genes are not allelic. This is confirmed by the phenotypic segregation ratio in F„. In crosses 15/4-2-1 x Ambra-S and Ambra-S x 15/4-2 - I shorter progeny than the shortest plants from the semidwarf parent were found. The degree and frequency of transgression was 7.7% and the frequency 2.27«. For the cross Ambra x 15/4-2, the degree of transgression was 6.27» and the frequency 0.9%. In the F_ generation, a great number of transgressive forms were obtained. In crossing GA insensitive (15/4-2) semidwarf plants with GA sensitive (1522) tall plants, different variation curves were observed, (Fig.6). The F~ variation curve has three or more peaks which gives ground r presuminfo s g tha n thii t s case more tha 2 segregatinn g gene pairs are present. Zitell d Martinan i ] note[7 i d thaundesirable th t e combination of short culm, low 1000 grain weight is one of the factors limiting the a sourc s f Nori a o f shor o e0 e 1 n us t culm. However, today, durum wheat cultivars having a short culm and large grains have been developed [l, 7, 12, 13]. e graiTh n yield perplant produce crossee th n i ds 15/4-x I 2- Ambra-S, Ambra- x 15/4-2-S d 15/4-2-1an 1cv.Nx o 1522-S indicatee th s existenc f considerablo e e diversit r sei;.idwarfo y f plants with high grain yield (Fig. 7,8,9). This shows that plants with suitable culm height and high yield can be selected by plant breeders. The Data concerning the relation between plant height and grain yield (Fig.7,8,9) show that a great number of F~ plants have a high yield surpassing the parental forms. It is possible to select plants with a culm

81 height withi e rang th d witnf 70-8 o an e hm 0c ver y high yield e chanceTh . r fo s selection are greater in the crosses of semidwarf with meduim height plants or the reciprocal lower chances for selecting high yielding plants exist when semi-dwarfs are crossed with typically tall plants. In this combination 9Fig.9) however vers i yt i , evident that individual plants wit a 70-8h m 0c culm height produce very high yield e resultTh . s for _ progenieF m s confirmed the above mentioned result d wil an e presentesb l a late n i dr paper. A tesG te Th performe _ seedF n o sd revealed that progenies wit e lowesth h t culm height obtained wer A insensitivG e d thosan e e withighese th h t culm height ones were GA sensitive.

Conclusion

Results obtaine e studth y b d demonstrate considerable differences in GA sensitivity existing in durum wheat lines and cultivars. It becomes evident tha A insensitivG t e semidwarf durum wheat mutants d cultivaran s having large grains coul e succesfullb d y use n breedini d g programmes aimin o develot g p lodging resistan d higan th yielding cultivars. With increased height, the GA response increased also. A positive correlation between plant height and GA response was found. The mutants or cultivars situated on the borderline between the GA insensitive and the GA sensitive are considered semi-sensitive. (MS). The genetic analyses made by us, to assess the mode of culm height inheritance, prove thae typ f th segregatioto e s determinei n e heighth y tb d of the parental forms. The results showed that the semidwarfing gene of mutants 15/4-2-1 and Ambra-S were not allelic.

REFERENCES

) (1 FILEY, K.A«," Induced mutatio duruf no m wheat with useful biological and economic charactera"»Genetic and cytogenetics in plants,(Jubilee Research Session,Sofia 1981),Sofia(1961) 161. (2) FILEY ,K.A."Utilisation of induced mutations and gamma radiatio cross-breeäinn ni duruf go m wheat", Induced Mutations A Tool in Plant Research,(Proc.Symp.Vienna 19ol )lAEAYienna (1981) 504.

(3) BOZZINItA.,BAGNARA,D.,MOSCONItG.,ROSSl,Z.,SCARASCIA-MOGNOZZA,G.f "Trend resultd san duruf so m wheat mutation breedin Casact ga - cia" Geneti breedind can duruf go m wheat(Proc.Symp.Bari 1973)» Bari(1973) 339.

82 (4) NAGL,K.,"Mutation experiments in durum wheat",Mutations in Plant Breeding II(Proc.Panel Vienna 1967),IAEA Vienna (1968) 293« (5) SIGUKBJORNSSCN,B.,MICKE,A.,"Philosophy and accomplishments of mutation breeding",Polyploidy and induced mutation in plant breeaing(Proc Meetingo tw f .o s Bari 1972),IAEA Vienna (1974) 303 • (6) KQNZAX,C,F.,"A review of semidwarfing gene sources and a description of some new mutans useful for 'breeding short- -stature wheats"»Inducet mutation Cross-breeding(Procn si . Advisory Group Vienna 1975) IAEA Vienna (1976) ,79.

) (7 ZITELLI,G.HARIANI,B.M.,"Realationships between dwarfness Agronomid (Norian ) nlo c trait durun si m wheat usen di breeding work(Proc. 4-th Wheat Gen.Symp.Columbia 1973)» Columbia 1973 ,617. C8) KONZAK,C.F.,SADAM MIR.,and DONALDSON ,E.,»Inheritance and linkage in durum wheats of semidwarfing genes with low response to gibberellin A~" Genetic and breeding of durum wheat(Proc.Symp. Bari 1973)» Bari (1973),29. ) (9 GALE,M.D GREGCRY,R.S.,"d an « A rapid metho earlr fo d y generation selection of dwarf genotypes in wheat"«,Euphytica 26(1977) 733- (10) MYHILL,R.R. and KONZAK,C.P.,nA new technique for culturing and measuring barley seedlings" Crop.Sei.7 (1967) 275» and , QUICKS. . J , (11) GALE,M..D.,MARSHALL,G.A.,GREGORI,R.S^"Norin 10 semidwarfism in tetraploiè wheat and associated effect on yield. Euphytica 30(1981)347-354.

83 (12.) SüARASCIA-i'IÜGNOZZA,G.T.»BA&MARAtD.,BOZZIHIfA.,«Mutagenesis applied to durum wheat:Resuits and Perspectives"»induced Mutation d Planan s t Improvement(Proc.study group 1972)> IAEA Yienna(1972) 183.

(13) ZITBLLI,G.,"Ned YALEGan . ,J A w high yielding italian durum wheat varieties",Geneti breedind an c g durum wheat(proc. Symp. Bari 1973)Bari (1973) 373«

TABLE I. GA RESPONSE OF DURUM WHEAT MUTANTS AND CULTIVARS WITH

DIFFERENT CULM HEIGH 100D TAN 0 GRAIN WEIGHO T THREE TH E LIGHT

TREATMENTS .

Mutantd an s Culm 1000 A reactioG n in % to water GA Cultivars. height grain control sensitivity cm weight g 7 days 7 days 7 dayn i s in light in dark dard an k 7 dayn i s Norin 10 light

Norin 10 62 35.6 105.2 100.1 99.6 I

65/1 65 32.4 104.4 99.3 95.2 I

15/4-2 70 52.0 101.2 98.2 85.4 I

Zever jana 72 50.6 99.7 99.4 97.7 I

Val no va 74 57.8 105.1 97.7 103.4 I

15/4-9 78 57.3 115.5 105.7 106.2 MS

Castelporziano 90 46.4 125.7 119.2 122.6 S -

Ambra 93 50.8 130.4 119.8 123.5 S

Lozen 76 95 52.2 118.8 112.7 115.3 S

65/2 105 46.1 126.2 112.4 121.9 S

1522 132 54.0 129.8 116.4 119.8 S

788 135 58.1 135.5 124.8 128.1 S

I - insensitive; MS - medium sensitive; S - sensitive 84 TABLE II. DATA MEAN CULM HEIGHT IN PARENTS AND HP O GENIES

Mutants and Number of Culm height Standard Variation cultivars x S + M deviatioplants n coefficient

15/4-2 - semi dwarf -I 4 8. 52 2 71.1. £ 3 11.78 Ambra - medium - S 0 9. 55 2 95.1. + 2 9.66 152 2- tal S - l 56 133.5 * 1.5 11.5 8.60

Fl 15/4-2- 1Ambrx S - a 29 72.5 * 0.9 4.9 6.76 Ambra- S x 15 A- 2-1 2 6. 25 2 74.1. * 8 8.29 S - 22 5 1 15/4- x I 2- 26 90.3 * 2.3 11.9 13.17

I — GA insensitive ; S - GA sensitive IM) tt 70 "t XO K5 •«) 9.1 UNI Mir. 110 Cnlin hciKlH (nu(

Fig. 1. Longest tiller h eight (cm) of F2 plants (n=32i) from the cross 15/4-2 (semi-dwar Ambrx ) l a - f(mediu . ) S m-

60 65 70 75 80 85 90 95 100 105 110 US 120 125 130 Culm height (cm)

Fig.2. Longest tiller heigh F plantt f (cmo ) s (n=224) froe mth 2 cross Ambra (mediuz 15/4- ) S m2- (semi-dwar. I) - f

86 63 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 Culm height (cm)

Fi g. 3. Longest tiller height (cm) o£ F2 plants (n=259) from the cross 15A-2 (semi-dwarf - I) x 1522 (tall - S).

65 60 55 50 45 40

35 30

20 IS

10 5

» I 3 11 0 11 5 10 0 10 5 9 0 9 5 8 0 8 5 7 0 7 5 6 0 6 5 5 Culm MfeM (cm)

Fig,4. Distributio 2 parentf ^ P culno P d md an an heighsA P f o t and F« Progenies from the cross 15/4-2 (semi-dwarf - I) x Ambra (medium - S).

87 5 13 0 13 5 12 0 12 5 11 O M 5 10 0 10 5 9 0 9 5 8 0 8 5 7 0 7 5 6 0 6 5 5 Culm height (cm)

Fig.5. Distributio ^ parent^ f P culP- no d d man an s heigh ^ P f o t

an 2 ProgenieF d s froe crosmth f Ambro s a . (mediux ) S m- x 15/4-2 (semi-dwar. I) - f

IÜ

35 r" P - 20

5 15 0 15 S U W l- 5 13 0 13 5 12 0 12 5 11 O H 5 10 0 10 5 9 0 9 5 8 W 5 7 0 7 5 6 0 6 5 5 Culm M{ht (cm)

Fig . 6 . Distributio , parent^ P. F d lud u ian e an s heigh ^ f P no f o t and Fg Progenies from the cross 15/4-2 (semi-dwarf -I) x 1522 (tall - S).

88 32

I/I 24 ob 20

£16 Ambr : ;*. © '. *«• •.. . .. a .v v;...:-.'•• • •'.'o ..•:•.••••. •• J 12 15/4-2../• • " ' . . •; ..' E

60 70 80 90 100 110 120 cm

Fig, .7 Relationship between culm heigh pland an t t y yielP n di population of 15/^-2 (semi-dwarf - I) x Ambra(medium-S)

^ 24 V) *•• è 20 "O 16 •.**•"• .• .••*. '©Ambra 15/4-2e//. .;•• : ; / H 12

60 70 80 90 100 J10 120 130 140cm

Fig«8. Relationship between culm height and plant yield in F2 population of Ambra(medium - S) x 15/4-2 (semi-dwarf - I),

89 32

^20

i, 16 15/4-2 •.* «.*0 v. I 12 •©1522 « 8

60 70 80 90 100 110 120 130 140 150 cm

Fig.9, Relationship between culm heigh pland an t t 2 yielP n di population of 15/4-2 (semi-dwarf - I) x 1522 (tall - S),

90 YIELD PERFORMANC 3 PROGENIEF F EO S FRO MDURUA M WHEAT CROSS INVOLVIN DIFFERENO GTW T SEMIDWARFING GENES: Rht 1 AND SD MUTATION*

B. GIORGI . BARBERAF , . BITTIO , . CAVICCHIONG , I Divisione Tecnologie Biologich Agrarieee , Laboratorio Produzione Alimentar i Baseed , ENEA, FARE, Casaccia, Rome, Italy

Abstract

Those present-day durum wheat cultivars suite highlo t d y fertile areas necesssarily have reduced height. This target has been achieved e mostlexploitatioth y b ye Nori th 0 gen 1 nf o ne Rhtl. Other genetic sources for semidwarfism have been found through mutagen experiments. The cultivar TITO has a reduced height from a semidominant SD mutation induced by gamma rays transferre parentse th f de o Cappelli froth ,e on m . Another cultivar, mutant CPB132, released earlie s Castea r l Porziano, CRESO, well known to Italian farmers, carries Rhtl as a major height-reducing gene. These cultivars were crossed to evaluate the effects of the two SD genes. e presencTh f theso e ee discriminateb gene n ca s gibberellia y b d n test at the seedling stage. All plants carrying Gai/Rhtl are insensitive whereas all the others were responsive to GA. F, families were selected by a GA seedling test for a spaced planted field trial. Each line was replicated 5 times and the following characters were measured or computed on an individual plant basis: plant height, number of tillers, biological yield, harvest inde d graian x n yield. Plants analyzed werf o e three types: i) semidwarf gibberellin insensitive; ii) semidwarf GA responsive and iii) tall GA responsive. These three classes correspond to three group f genotypeo s se presenc baseo th independen tw n o df o e t , analysesF d genean e firs « Th s evidenceF .a s te grouth y b dp comprises both homozygou d heterozygouan s D genesS e o Th tw .s e plantth r fo s second group has only one SD gene and is GA responsive. The third group includes only tall plant sD genes S wit e numbeo n hTh . f planto r s that fall into each group was close to the expected ratio of 12 : 3 : 1. Tito is about 10 cm taller than Creso, has a lower number of tillers, larger spikes, more grain r spikeletspe a lowe t r,bu 1000 kernal weight, so that the two cultivars are similar in yield potential, via their similar balanc f yielo e d components.

The three F~ populations showed, as expected, a strong positive correlation between heigh yieldd an t . However, differences were found among the overall means of the F, families. In particular, the homozygous F- lines carryin Gail/Rhte th g l allele showe highea d r yiel r planpe d t compared to both the semidwarf and tall GA responsive F_ populations, indicating that the Norin 10 Gail/ Rhtl gene must have beneficial pleiotropi r linkeo c d effect n otheo s r characters, particularl componente th y s

* This researchewore parth a f s ki o t s carrie t withidou framewore nth FAOe th f ko / IAEA Co-ordinated Research Programm Evaluation eo Semi-dwarf no f Cereal Mutantr sfo Cross Breeding.

91 of yield. This however does not necessarily mean that other SD genes, including those induce y mutagensb d , mus e discardedb t t simplI . y implies that other yield component character se manipulate b hav o t e d in way o compensatt s y associatean r fo e d differencism beneficial effects on yield. This task seem havo t s e been accomplishe n breedini d e th g . Tito e higcv Th .h numbe_ lineF f o sr which performed better than Creso suggests that further improvement e combinatio th e mad b y b en ca s f traito n s o cultivarstw froe th m .

Introduction

The most remarkable event in the history of wheat breeding, very likely, is represente e shorth y tb d straw revolution. Plants with short stature d stilan l stra e resistanar w o lodgint t d bettean g r adapte o intensivt d e managemen d higan th production conditions than tall cultivars, besides being more suitable for combine-harvesting. The result has been increased yield with the concurrent decrease in the height, as demonstrated in most wheat growing countrie worlde th f .o s Lookin e evolutiog th bac o t k n of modern wheat varieties t appeari , s thaprocese th t r reducinfo s g plant stature as a means of increasing yield was tremendously accelerated by the introduction of Japanese wheat germplasm. First, Ingegnoli in the beginning of this century brought a few Japanese varieties of common wheat to Italy, so that N. Strampelli in 1913 could cross Akakomugi, Shirobozu, Akabozu and Sumagawa Daruma with the tall and late land variety Rieti and in 1920 released the cv. Ardito, the first semidwarf and early variety [i]. After World War II, S.C. Salmo n 194i n 6 imported into North America5 ,1 seed Norif an o d 0 1 n other varieties of this type [2]. The first wheat breeder in USA who used Norin 10 and other semidwarfs extensively was O.A. Vogel. A series of crosses including Norin 10 X Brevor and Norin 10 X Baart were made at Pullman (Washington) in 1949. The transfer of Norin 10 genes for dwarfnes duruo t s m whea s accomplishewa t Borlauy b d g (Mexico d Lebsoc)an k (North Dakota breediny )b g programmes initiate n 195i d d 19564an , respectively [5,6]. The semidwarfism of- the Italian bread wheat varieties is also controlled by two major genes which are located, according to C.N. Law, on the chromosomes 2D and 5B (7B) [?]. The former genes are associated with gibberellin insensitivity, the latter are associated with a normal response to gebberellin. These two genetic semi-dwarfing systems so far have been exploited at different times and in different areas so that at the moment it is difficult to say whether the Norin 10 genes per se definately have pleiotropic positive effects over other semuwarfing genes, even though the first studies point to positive effects of these genes on yield. No cultiva f commoo r n wheat presently grow n Itali n y carries Nori0 1 n genes. A different picture comes from the list of durum wheat cultivars. Three different sources of short straw genes are present in this crop. Cultivars Creso, Valnova, Karel and many others have one semidwarfing gene, Rhtl, coming from Mexican material introduce e earl Italn th i d yn i y sixties and used in different breeding programmes. A second group of cultivars such as Lambro, Granato, Gabbiano and Ringo are semidwarf types due to the oresence of plant height reduction gene(s) from Akakomugi transferred through hybridization witcommoe th h n wheat varieties Mentana, Mara, Marzott Acciaiod an o A thir. d grou f cultivaro p s suc s Castela h - porziano, Castelfusano, Casternuovo and Casteldelmonte are the result of the direct use of short straw mutants, whereas Tito and Augusto derive from a cross-breeding programme involving mutants and the tall American variety, Lakota. The cultivars Creso and Tito, as representatives of the firs d thiran t d group respectively, have been crosse analyzed an d? F n i d

92 and F- to study the relationship between two different semidwarfing sources and yield. Materials and Methods

Both Creso and Tito have been bred at Casaccia Nuclear Center, CNEN (now ENEA). e firsCresth s ti o semidwarf, gibberellin insensitive variety widely grown in the central part of Italy. It is high yielding and has a high 1000 kernel weight. Tito is about 10 cm taller and 3-4 days later than Creso t showI . s good cold resistance, elastic culms an higa d h yield potential [8]. Three hundred F~ grains along with fifty grains from each parent were sown in Jiffy-pots in December 1980. In the second fortnight of January 1981, 250 uniform plantlets were transplanted in the field 30 cm apart. At maturity, all plants were harvested and the heights were recorded before each plan s threshedwa t . Becaus f biro e d damage e yielth r , pe d plan „ s plantmeaninglessF wa t 0 25 s gavf o et .ou enoug Onl3 16 yh seed to proceed further with GA seedling tests and with a spaced plant field trial. Thirt , seedF y s from eac „ planF h t were soake n distillei d d water an aftery d da lef e ,t Th seedovernigh . C s 4 wer t a te transferred between two sheets of filter paper, arranged in a special plastic rack and placed icontainea n r 0 witp.p.m1 a h . GA., solution. Seedling development took place in the growth chamber at 20 1 C and with a photoperiod of 18 hrs. light and 6 hrs. dark. The GA- solution was replaced twice during the growth period. After 8 days, seedlings were classified into two groups: GA- insensitive and GA_ responsive on the basis of internode elongation and the general etiolated appearance of the seedlings. In this way, the F_ plants were classified as homozygous insensitive, homozygous responsiv heterozygousd an e . Thirty-siA G x insensitiv A responsiv G _ familieF e4 4 d , an familiesF e s werea user fo d spaced plant field experiment e seconTh . d - progengrouF f o p y allowed the distinction between semidwarf plants carrying the SD mutation and tall plants wwith no SD genes. Each F_ family was sown in rows of 12 plants, spaced 10 cm within and 20 cm between rows. A split-plot, randomized- block design with heights as the main plots and individual lines as sub-plots was used. Each F- progeny was replicated 5 times. The end plants in each row were discarded to minimise edge effects. Sowing started on December 12, s completewa d 198an 1 d afte 3 daysr . Fertilizatio s dornwa a with ammonium nitrate applie a 3 timed r fo s tota g nitrogek l 0 amoun 15 hectarer pe nf o te followinTh . g characters were measured or computed on an individual plant basis: plant height, tiller number, biological yield, harvest index and grain yield. Weeds were controlle y hanb d d pulling.

Result d Discussioan s n

Plant height of F2 plants showed a wide variation with individuals shorter and individuals much taller than either parent (Fig.l). This is a clear indication that the two semidwarfing genes are not allelic. The GA„ test performed on F- seeds revealed that out of 163 F~ plants, 36 were homozygous insensitive, 83 segregated sensitive and insensitive and 44 were homozygous responsive. The chi-square analysis gave a segregatior fo goot fi d n rati f 1:2:expectes o a 1 d from previous work [9]. A small fractio f abouo n t 10-12 plants were shorter than Creso, indicating the presence of both semidwarfing genes (Fig. 1). By combining the F_ plant height distribution with gibberellin tes t_ seedsF dat n o a, three group f plantso s coul e detectee correspondinb d th d an d g segregation ratios

93 of 12:3:1 are expected on the assumption of two independent genes hypothesis. Out of 163 plants, 119 had one or two doses of the Gai/Rhtl gene 2 plant;3 d gai/rhtha s l geno doses tw D mutane S r wito ;e e th th on gen n i e 12 plants were double recessive, that is, with no SD genes. The number of plants observed in each group was in good agreement with expectations as shown in Table 1. In the presence of tie Rhtl allele, the effect of the D mutatioS s additivi n e wit a hcapacit o reduct y e plant height furthey b r . aboucm 5 1 t

The mean height of the GA insensitive F- families ranged from m witc n overala 7 h7 o t l 2 mea6 f 70. o nwhic, 4e cm clos s th i h o t e plant height of Creso, 71 cm (Fig.2, Table 3). The mean height of the GA responsive and semidwarf F_ families varied from 78 to 88 cm with an overall mean value of 82 cm. Plant height of Tito was 82 cm. The tall FT families had a plant height of 121 cm, ranging from 108 to 135 cm. Significant genetic variation was found among F~ families belonging to each of the three plant height genotypes as shown in Table 3 and Figure 2. Other characters, particularl e yiel r planth y pe d t show variation between lines. The positive relationship between plant height and yield is similar to that found previously by different authors in both common and durum wheat [10,11]. As to the yield potential, the F, Gai/Rhtl families ranked first wit a smalh t consistenbu l t advantage ovee gai/rhtth r . F l families carrying the SD mutant gene. The tall F_ families were significantly less productive than either semidwarf population. Plants carry- e Rhtinth gl gen d moreha e tiller a better plan pe d s an tr harvest index compared with rhtl plants, independent of the presence of other dwarfing genes. However, plants wit a relativelh y short stature seeme havo t d e better features thae talth n l ones, other than their greater lodging resistance (Table 3). Biological yield was practically unaffected by the prescence of other dwarfing genes, whatever be their nature. However, Creso yielded slightly more biomass and strikingly showed a less favorable harvest index tha o cultivarntw Tito e mord Th .ha s e or less the same yield potential but different plant architecture and physiological characters resultin a simila n i g r balanc f compensatino e g yield components n centimeter.Te f heighso t increas n advantaga s i e e for -the cv. Tito in terms of yield but is at the same time a drawback, bein e uppeth g r limit compatible with lodging resistance. Lookine th t a g A responsivG d semidwaran e - familieF f s (Fig.2) appeart ,i s thaTite th to type is nearly the best expression among the group of 32 randomly selected lines. More chance r improvinfo s g Creso see exiso t m t amone th g A insensitivG _ familieF e s sinc _ lineF groua e5 s f o p(Fig.2 ) performed better than the best parent. The Gail/Rhtl gene has a dramatic effect on the heigh f duruo t m wheat. Consequentl t seemi y s rather difficulo t t selec r "tall-dwarfsfo t " beyon certaia d n limit e tallesTh . , familF t y scored in this study was only 77 cm.

n conclusioI n evidenc a pleiotropi f o e c positive effec n yielo t f o d the Norin 10 gene Rhtl has been presented. However, the SD mutant gene incorporate . Titcv oe appearth n i d s also suitabl breedinr fo e g high yielding varieties provided thae yielth t d component e adjustear s o t d compensate for the different association of effects on yield as shown by the present results.

94 REFERENCES

[I] STRAMPELLI, N., I miei lavori: origin! e sviluppi, i grani della Victoria (1932) 48.

] REITZ[2 , L.P d SALMONan . , S.c., Origin ,Norif o historie 0 e 1 nus d an s wheat. Crop Science 8 (1968) 686.

[3] BORLAUG, N., Wheat breeding and its impact on world food. Proceed. 3rd Int. Wheat Genet. Symp. (1969) 1.

] LEBSTOCK[4 , K.L., Transfe f Norio r gene0 1 ndwarfnesr fo s duruo t s m wheat. Crop Scienc (19633 e ) 450.

[5] GALE, M.D. and MARSHALL, G.A., The chromosomal location of Gai 1 and Rhtl genes for gibberellin insensitivity and semi-dwarfism in a derivative of Norin 10 wheat. Heredity 37(1976) 283.

[6] GALE, M.D., LAW, C.N. and WORLAND, A.J. The chromosomal location of a major dwarfing gene frow Britisne m n Norii h0 1 nsemi-dwar f wheats. Heredit 5 (19753 y ) 417.

[7] LAW, C.N., SNAPE, J.W. and WORLAND, A.J., Intraspecific chromosome manipulation. Phil. Trans Soc. .R . 2 (1981Londo29 , 8 )n 509.

] BOZZINI[8 BAGNARAd an . ,A , Creso ,D. , Mid Titoe a , nuovi grani duri dalle eccellenti prestazioni. L'lnform. Agrario 35 (1974) 20347.

[9] BLANCO, A. and SIMEONE R. Genetic Control of Gibberellic Acid Insensitivit n Semidwari y f Durum Wheat (Triticum durum Desf.). Z. Pflanzenzüchtg 88 (1982) 185.

[10] LAW, C.N., SNAPE J.W. and WORLAND, A.J. The genetical relationship between heigh d yiel an twheatn i d . Heredit 0 (19784 y ) 133.

[II] JOPPA, L.R., Agronomic Characteristics of Near-Isogenic Tall and Semidwarf Line Duruf so m Wheat. Crop Scienc 3 (19731 e ) 743.

95 TABLE 1. SEGREGATION RATIO 0F F PLANTS IN THE CRESO X TITO HYBRID INVOLVING TWO SEMIDWARFING GENES

Génotypes I Rhtl/Sd s r o D rhtl/SD or sd rhtl/sd | Plant 1 : 3 : 12 \

VO | Expected Ratio 12 Os I F plants expected 122.3 30.6 10.2

I | F plants observed 119 32 12 ! 1,85

* SD = Semidwarfing mutant gene incorporated in the cv. TITO. TABLE 2. MEANS FOR NINE CHARACTERS OF TWO DURUM WHEAT CULTIVARS CARRYING TWO DIFFERENT SEMIDWARFING (SD) GENES

v Chara^ c ters Semidwarfing No. of Ear Plant Tillers Spikelets Grains 1000 Biomass Harvest Yield \. Genes Plants Emergence Height per per per Kernel per Index per Time Plant Ear Spikelet Weight Plant Plant Cultivars >v \ cm g g g

1 1 1 1 1 1 1 1 0 8 Gai/Rht1 CRES| Ol 15 May 71.5 4.74 20.4 2.39 60.5 | 31.3 011.5| 0.387 1 1 1 1 i i *» ** * «ft *• 1 i TITO SD Mutant 80 18 May 82.0 3.86 21.8 3.69 46.5 28.95 0.39 11.29

1 ! 1 1 1 1 1 1

) * tl : They indicate significant differences between two cultivars at P ^ 0.05 and 0.01 respectively. TAB. 3. MEANS FOR FIVE CHARACTERS IN RANDOm GAl/Rhtl

. ^X Characters No of Plant Tillerf o . No s Biological yield Harvest Yield height per per plant per plant F3 Index . Parent^v d san Families cm plant F Familie\ ^ s g- g- 3 ^N.

CRESO 71.5 4.74 31.30 0.37 11.58

00 ** ** TITO 82.0 3.86 28.95 0.39 11.29

o o 0 o o o F Families Rhtl 34 70.4 4.22 29.11 0.38 11.06 3 0 ** 0 o * 0 00 * F Families rhtl Short 32 82.2 4.01 28.86 0.35 10.10 3 00 ** 00 •»# o 0 #* 0 0 ** F Families rhtl Tall 32 121.1 3.26 28.50 0.30 8.55 3

* 1) These symbols refe significano rt t differences between Rhtrhtd an ll genotype P 0.0 t sa 0.01d 5an , respectively.

00( The circles: indicate the presence of significant genetic variation between lines within genotypes. 10 CRESO - Plant Height Distribution

TITO »t " "

20 Homozygou2 F n InsensitivA G s e Semidwarf Plants >- V_cJ O) £* Homozygous GA Responsive Semidwarf Plants

0 10 5 0 0 7 115 130 Plant heighm c t

Fig.1- Plant height distributio 2 populatioF a n ni n fro e CRESmth OTITx O cross

. Gai/RhM P3 Semi-Dwarf (SO) families o gai/rhtl Pj families with a SO mutant gene 14 A gai/rhM fall families 13

o» • 12 •«$$ n

* / / 2 8 / Ul 2 ° //A 7

0 12 0 11 0 10 0 9 0 8 0 7 0 6 130 140

MEAN F3 PLANT HEIGHT (cm)

Fig.2. The relationship between yield per plant and height of 3 P$ populations from the

cross CRESO with TITO 99 SEMI-DWARF MUTANTS IN TRITICALE AND WHEAT BREEDING

C.J. DRISCOLL Departmen Agronomyf to , Waite Agricultural Research Institute, Glen Osmond, South Australia, Australia

Abstract

The triticale lines Beagle and DR-IRA have been subjected to ionizing

irradiation and chemical mutagenesis in order to produce semi-dwarf

mutants m talc d m .DR-IRundec an l0 0 Beaglr10 8 A averags i e e field conditions. A bulk then pedigree method is currently represented by 158

single plots of M,. (or in some cases M) mutants that are from 5 to 35 cm ? shorter than the control variety. The shortest mutants are 65 cm in

height. Forty of these mutants are also earlier flowering than the control

varieties. Replicated yield testing will be conducted on confirmed mutants

in 1983. Respons o gibberellit e c aci f theso d e mutants will alse b o

determined. e CornerstonTh e male-sterility mutant (mslc')s n chromosomha o a 4A m ear

been combined wit GA-insensitive/reducee hth d height gene Gai/Rhtl whics hi

also on chromosome arm 4Act. The mslc mutant has also been combined with Gai/Rht2 on chromsome 4D and with both Gai/Rhtl and Gai/Rht2, The combination mslcd Gai/Rhtlan s beeha n e basichosecomposita th f o s a n e

cross. Thirteen varieties were tested with GA« and seven (Warigal, Aroona, Oxley, Banks, Avocet, Matip d Toquifenan o ) which contain Gai/Rhtl were

crossed with mslc Gai/Rhtl d enterean d int n interpollinatina o e Th - F g 2 entire composit s homozygoui e r thifo ss semi-dwarf allel d selectioan e n will be practiced for increased height on a GA-insensitive background.

101 1. Introduction Semi-dwarf mutants have often been associated with yield increases.

This paper describes two experimental approaches to grain yield increases

involving semi-dwarfism. The first involves induction of semi-dwarf

mutants in high-yielding lines of hexaploid triticale. The second involves selection for increased height on a background of homozygosity for a major

gensemi-dwarfisr fo e wheatn i m .

. 2 Triticale

e hexaploiTh d triticale selections Beagl DR-IRd an e A each contaie nth fule chromosomry l e complement n SoutI . h Australia their usual height s excessivi ; ) DR-IR(Beagl cm cm d lodging 0 0 an e9 A 10 e , especially with

Beagle t uncommonno s ,i . Both triticales yield wel d inducelan d semi-dwarf

mutants could result in even greater yields. Two treatments were separately applie o grait d f thes o no varietie tw e. M.A Mr . y Rajputb s f ,o

the Atomic Energy Agricultural Research Centre, Tandojam, Sind, Pakistan,

while at the Waite Institute as an I.A.E.A. Fellow in 1977. The seed

treatments K radwer 5 s2 e y grai X-raydr d 0.5 an no S followin t %sEM g

soaking with distilled water. Five hundred seeds of each variety were

subjected to each treatment. A bulk then pedigree metho s usedwa d . This involved four bulke« dM populations from which 219 short and/or early plants were selected and _ row M 1979n thesef plantei s9 O .21 9 rows ,4 a d s were selecte growd an d n as 49 M, rows in 1980. These rows segregated for various levels of height and a total of 399 plants were selected from them and planted as 399 M,. rows in 1981. Of these, 158 rows were selected and grown as 158 plots in e hundre1982On d .thirtwhic, an d 28 thesf hd o y an requiree , plotM e sar d

seed increas e 1980/8th n i e1 summer generation_ M e eac. ,ar M, h t mutanA . t row was given a distinct number and those numbers have been carried on in

102 plot subsequenn i s t generations. Figur illustrate1 e controa s mutand an l t

MS Beagle row. The rationale was that semi-dwarf mutants of decidedly poor agronomic performance were eliminated before time-consuming record keeping

commenced. However e late,th r generations will include duplicatee th f o s

one mutation event.

Of the 158 M,o or M-/. selections (Table I) there are more mutants with X-rays than EMS and more mutants 85 cm or less with Beagle than DR-IRA;

however, no significance is attached to these differences. It is

interesting to note that approximately a quarter of these mutants are also

earlier flowering. a verThi s yi s high proportion e earlinesTh t . no s i s regarde n indicatioa s a d f outcrossino n g becaus e generath e l plant typs i e

similar to the original type and hence the selections are regarded as

incidence f mutationso s . Earlines s usefui s n thai l t Beagl d DR-IRan e A

ara little e latr manfo ey region f Australio s a (DR-IR 5 day13 o At s

anthesis and Beagle 125 days compared with Coorong triticale 112 days).

e putativTh e mutants thae onlar ty slightly reduce n n heighi i d y ma t

mutantreflece y b ma fac o t t e showb tstbu t misclassificationsno n . Also, , rowM se th requiresom f o e d roguein talf o g l segregants. Henc totae eth l

number of 158 mutants may be reduced to a considerably lower number after

height observations are made in 1982. Others may be eliminated because of e continuinth g eliminatio thosf no e with poor agronomic type. The retained lines will be subjected to replicated yield trials over gibberellio t site d san c acid insensitivity tests.

. 3 Wheat

It has been postulated [1] that height increments to semi-dwarf wheat y lea o ma grait d n yield increments e rationalTh . thas gibberellie i tth c / acid sensitivit s beneficiai y o yieldt l ; however e pleiotropith , c reductio heighexcessivf e no b y t ma shoul d ean correctee db minoy db r genes for increased height.

103 Aggregation of minor genes for height would be optimized in a composite cross basea male-sterilit n o d y mutant e restrictioTh . thas i n t all components of the composite cross are homozygous for the same GA-insensitive allele. Selection for increased height can then be applied durin a numbeg f generationo r f randoo s m intercrossing e randomnesTh . s aspect optimize possibilite th s aggregatiof yo minof no r genes.

The male-sterile line used in this research is Cornerstone, which involves a T-ray induced recessive mutation for male sterility [2,3]. Figur 2 illustratee s this mutant mutante Th . , znsic s locatei , least a d t

50 crossover units from the centromere on the a arm of chromosome 4A [réf.

4] . The Gai/Rhtl allele is also located on this chromosome arm and

Gai/Rht3, which is allelic to Gai/Rhtl, has been located 15 ± 3 crossover units from the centromere [5]. Homozygosity for mslc and Gai/Rhtl have been combined in a WW-15 based Cornerstone stock and lines involved in the development of this stock served as female parents for the Composite Cross.

Fourteen varieties were examined for possible use as male parents in this composite. These are regarded as possessing the Gai/Rhtl allele [6]. These were sprayed at the 2-leaf stage with gibberellic acid (100 ppm aq.) mixed with wetting agent (Agrol) and scored 6 to 7 days later.

Seedlings were score followss a d : : = sensitiv showin3 ge very marked elongation. The variety Halberd is used as a standard for this rating. 2 = intermediate : showing some degree of elongation. 1= +insensitiv : showin eslighga t amoun elongationf to . a standars use WW-1i s a d5r thi fo ds rating. 1 = very insensitive : showing no response at all.

104 Table II shows the response to GA„ of the 14 varieties examined. The

large differences between the two accessions of El Gaucho and the two

accession f Cooo s k reflect presenc d absenc an ea Gai/Rht f o e allelee Th .

minor differences with Matipo (l+,2), Arvand (2,3 d Wre)an n (2,3y )ma

reflect conditions of seed maturity in the previous generation; however,

tha s speculatioi t n only.

The first thirteen varieties listed in Table II were crossed to a

Cornerstone procese stocth n kf beini o s tha s gwa t backcrosse o WW-15t d .

Some of the female parents used in these crosses were homozygous Gai/Rhtl

and also heterozygous Gai/Rht2 and others were heterozygous for Gai/Rhtl.

Hence, not all F 's were of the required Gai/Rht genotype which led to

exclusion of some of these crosses at this stage.

Eight F~ populations were raised and one, involving Arvand, reacted

excessively to GA application and was excluded. Of the seven that were

accepted (Tabl ) oneII e , involving Banks, showe a slighd t amounf o t

segregatio ; nevertheless F_ A reactio G e r th fo nn i n l seve,al n were scored

as homogeneous for a 1+ reaction. Residual seed was used to establish seedling f theso s e seve » populationF n s under glasshouse conditions. They

were then randomly mixe d transplantean d e fielth dn betweei m dc wit 5 2 h n

plants, and alternating 25 cm and 45 cm between rows. These spacings, arrange a square s a d , allow effective pollinatio plantl accesd nal an o st

i ntheg ordeta m o whert n being classified male fertil malr eo e sterile.

e mixe Th ~ populationF d , which contains abou s 0 i plant80 td an s plante n isolationi d , will segregate approximatel 3 fertily 1 mal : e sterile and the male steriles will be pollinated by random fertiles from any of the seven crosses. The Composite Cross will be managed in the same o earlier-establishetw e th s a y wa d composites whic designee har yielr fo d d increases without cognizanc f GA-reactiono e . Seed wil e takeb l n from male-sterile plants only. Selection wil made r increaseb l fo e d heighy b t

105 taking seed from the taller male-sterile plants. Three rounds of

outcrossin e plannedar g , followe y eliminatiob d e allel th r mal f fo eo ne

sterilit yield yan d testing.

REFERENCES

[I] Gale, M.D., Law, C.N., "Norin-10 based semidwarfism", Genetic

Diversit n Plantsi y . (Muhammed n Borstel , AkselVo A. ,, R. ,,

R.C., Eds), Plenum Press Yor w Londod ,Ne k an n (1977). ] Driscoll[2 , C.J., Barlow, K.K., "Male sterilit plantsn i y : induction,

isolation and utilization". Induced Mutations in Cross-breeding,

I.A.E.A., Vienna (1976) 123.

[3] Driscoll, C.J., Registration of Cornerstone male-sterile wheat

germplasm. Crop Sei. 17 (1977) 190. ] Barlow[4 , K.K., Driscoll, C.J., Linkage studies involvino tw g

chromosomal male-sterility mutants in hexaploid wheat. Genetics

98 (1982) 791.

] McVittie[5 , J.A., Gale, M.D., Marshall, G.A., Westcotte Th , B. ,

intrachromosoma m ThumTo l b d mappine Norian dwarfinth 0 1 nf o g g

genes. Heredity 40 (1978) 67. ] Gale[6 , M.D., Marshall, G.A., Rao, M.V. A ,classificatio Norie th nf o n 10 and Tom Thumb dwarfing genes in British, Mexican, Indian and other hexaploid bread wheat varieties. Euphytica 30 (1981) 355.

106 TABL : I E198 2 plot f M,(o o sn som i r e case selection) sM_ s accordin heights_ M o t g .

heigh, M neareso (t t t 5cm) in 1981 Total

0 8 5 8 0 9 95 75 70 65

DR- IRA (EMS) 8 9(3)*4(1) 1 0 22 (4)

DRA (X-rays-IR ) 16 9(4) 8(2) 5(1) 3(1) 41 (8) 1 1 Beagl ) (1 e 0 (EMS1 ) 7 2 6(1) 4 0 40 (2) Beagle (X-rays) 2 4 12 12(11) 16(10) 8(4) 1 (1) 55 (26)

* numbers in brackets are included and are the numbers that were also early. Controls: DR-IRA 90 cm, 135 days to anthesis Beagle 100 cm, 125 days to anthesis

107 TABLE II: Responses to GA- by varieties examined for inclusion in Composite Cross.

Variety Accession numbe d sourcran e Respons_ GA o t e

WARIGAL -K85— 4 Waite Institute collection 1 AROONA **K819 Waite Institute collection 1+

OXLEY K530 J. Syme, Queensland, W.R.I. 1+ **K995 M. Gale, Plant Breeding Institute, Cambridge 1+ BANKS **K905 S.A. Department of Agriculture 1+ AVOCET **K904 S.A. Department of Agriculture 1+ K996 M. Gale, P.B.I. 1+ MATIPO **K992 (Matipo Bulk Gale. )M , P.B.I. 1+ K898 K. Symes, Aust. Wheat Collection 2

TOQUIFEN K902 K. Symes, A.W.C. 1+ TOQUIFE" "S N **K993 M. Gale, P.B.I. 1+

ARVAND *K990 M. Gale, P.B.I. 2 K899 K. Symes, A.W.C. 3 K903 K. Symes, A.W.C. 3

EGRET *K486 Waite Institute Collection 1

CONDOR *K485 Waite Institute Collection 1+ K994 M. Gale, P.B.I. 1+

EL GAUCHO *K991 M. Gale, P.B.I. 1+ K901 Symes. K , A.W.C. 3 COOK *K988 Type sample, K. Symes, A.W.C. 1+ K906 S.A. Departmen Agriculturf to e 3

ZAMBESI K900 K. Symes, A.W.C. 3? ZAMBESI II *K989 M. Gale, P.B.I. 2

WREN K912 National Rust Nursery, Castle Hill, N.S.W. 2 K987 A. PugsleSymes. K a y,vi A.W.C. 2 K897 Symes. K , A.W.C. 3 WW15 Insensitive Control 1+ Halberd Sensitive Control 3

* Crossed to- Cornerstone . •• * Crosse* Cornerstono t d included Composite an th n i d e Cross

108 1. ) Contro cm (righ2 0 35 8 lmutan. d : t BeaglNo an S ) tM cm e 0 (lef10 : t This mutan alss ti o distinctly earlier flowering than control Beagle.

109 Cornerstone spikA th f eo . 2 e male-sterility mutant.

110 GENETIC STUDIE DWARN SO F TRITICALE MUTANTS

S. NALEPA* Institute of Plant Breeding, Krakow, Poland

Abstract

The parents, F.. , F» and backcrosses derived from triticale dwarf mutants and tall cultivars were studied during the 1979-80 crop season. Dats takewa a n individuao n l plant o estimatt s e dwarf inheritance, gene action and interrelationships of grain yield and selected yield related traits. The direct and indirect effects of grain yield per spike on other grain yield component s alswa s o studied. Results indicate that dwarfing is controlled by two, partially dominant, genes. Additional crosses involving other hexaploid triticale lines reveale e inheritancth d f otheo e r characters e resultTh . s - ishoF n w that glossy plant, waxy coverin e necd th an k f o g hairy nece dominantar k , while short stra s recessivei w . Waxy covering on the spike seems to be controlled by two genes with additive action. Observation of F« progenies indicate that a genwaxr fo ey neck covering d hairan yx W nec £ mighH k e locateb t d e samth e n o chromosom a distanc t a e f abouo e 9 units1 t . Plant height showe a positivd e phenotypic correlation with grain yiel d 1,00an 0d kernel weight. Non-significant correlations were found between plant heigh d numbean t f graino r r spikepe s , harvest inde d spikelean x t fertility. Path coefficient analyse e phenotypith t a s c level indicated that the direct effects of grain number on grain yield was large whil e directh e t effect f 1,00o s 0 kernel weighs wa t relatively small. The results of this study indicate that selection for high kernel e mosnumbeth t s i rimportan t facto a breedin n i r g programme for increasing grain yield in some dwarf triticale. s founIwa t d that epistasi t involve no e inheritanc th s i sn i d f o e harvest index. Additive, dominanc d additivan e x dominance e epistasis were important for grain yiel r spikepe d A duplicat. e typ f epistasio e s founswa d for 1,000 kernel weight and number of grains per spikelet.

INTRODUCTION A program on chemically induced nutations in the winter form of triticale was initiated in 1972 at the Plant Breeding Institute in thif o sm Krakow investigatioai e Th . obtaio t s nwa dwar senri.d fan - dwarf forms and to learn •whether by means of mutations, the unfavorable correlations, especially those between culm length and yield components,

* Present address: Dessert Seed Co., Inc., Salinas, California, USA.

Ill coul brokene db . Four form wintef so r triticale primar,a y hexaploid, and primary octoploid, together with a secondary hexaploid and secondary octoploid were treated with two chemical mutagens, nanely N-nitroso- N-methylurea (NMH) and N-nitroso-N-ethylurea (NEH). It was found that variatio considerabls nwa ^ generatioe thath ~ yM n ni e large th n n ri (Grzesik, 1980). Dwarf and semi-dwarf mutants were selected in M£ and Hj generations and were evaluated in the Me. Analyses of the mutants showed that despite the considerable shortening of the culm, 30-50%, in several mutants, a reduction of yield components did not occur. These dwarf forms are characterized by a favorable harvest index as compared to the control. The objectives of the present study were: determino 1T . modea inheritancf eo straf eo w lengt somd han e other morphological characters. 2. To estimate the coefficient of correlation between straw length and yield components. characterizo 3T . gene eth e action.

MATERIALS AND METHODS

Two varieties were chosen as parents for this study. One line, B-2051, meawhica d s nchoses h ha it plan wa r m nc tfo heigh5 14 f to "normal"height othere Th . ,dwara f mutant Tm-100»was chosen because it's mean plant height was 60 cm. These parental lines were breeding true and for the purposes of this study, considered to be homozygous. Th deriveed parentsan 2 F d backcrossesp ,F , BC^ ^ wer,K e studied in 197fiela n 9i d experiment Departmen e growth t na Cereaf to l Crops in Krakow experimene Th . arranges twa randomizea n di d complete block design, with four replications minie Th . m numbem genef ro s controlling the expressio straf no w lengt estimates hwa d fro mformula a devisey db Castle-Wright. Informatio genetinature e th th f n eno o c effectr sfo each characte patternes rwa d afte modera l suggeste Mathey db r (1949) and Mather and Jinks (1971). Simple correlation coefficients were made between all possible combinations of traits related to culm length. These correlation coefficients were further analyzed using Wrights path coefficients. RESULT DISCUSSIOD SAN N 1. Inheritanc Straf eo w Lengt somd han e other Morphological Characters. F, and BC,, BC2 frequency distributions for the crosses involving the dwarf mutant Tm-100 and the tall line, B-2051 indicate that the genes 112 for dwarfing are acting in a partially dominant manner (Figure 1). The F-, and BC, plants ware 6 on and 8 on shorter than midparent respectively. plant2 F s coul classifiee db d intfoue oth r height groups; semi-dwarf, tall, shor dwarfd tan BC,n I ., therseparatioa s ewa n intdistinco otw t classes; dwarf and semi-dwarf, while in IX^,, the two classes were senrL- dwarf and tall. Data from table 1 indicate that the F£ produced 86 semi-dwarf, 35 tall dwarshor7 9 , 1 d ftan plants. This indicates tha independeno ttw t gene pairs segregate in a ratio of 8 semi-dwarf : 5 tall : 2 short : 1 dwarf. In the BC, generation, a 3:1 genetic ratio was indicated, namel semi-dwary3 dwarf1 : f^ generationK ,e whilth n ei , thers ewa a 3:1 ratio of 3 tall : 1 semi-dwarf. These results are to be expected assumin complementaro gtw y dominant dwar e geneth ff si plan s twa homozygou bott sa h loci estimatee Th . d minimm numbe genef ro s controlling culm length expressio 1.44s nwa . Assumin modee gth l wit partiallo htw y dominant genes, dwarf plants would have horaozygous dominant genes at both loci, DjDjp^ (Table 3)- Semi-dwarf plants would be heterozygous at both loci, I^d^1^.o r ârozyS3(ls at o116 locus, D^ and heterozygous at the other, DÎty^ or î^P^2' Short P131^8ar e homozygous recessive at one locus and homozygous dominant at the other locus, or ^l^lPz^Z* Ta"^^ P^3^^3 are recessive at both loci, °r heterozygous at one locus and homozygous at the other, or d-id-id^«. To verify F£ data, F, progenies from selected F£ plants were studied but unfortunately some loss of plants occurred

in the winter of 1980-81. Dwarf plants classified in the F2 were also classified dwarf in the F«. Semi-dwarf plants segregated for all height groups. Additional crosses involving other hexaploid triticale lines revealed the inheritance of other characteristics. In addition to plant height, the parent lines differed in the following traits: hairy neck (small section of the peduncle below the spike) ; spike and neck waxiness; gloss waxs yv y lea sted fan m characteristicse Th . sho£ F wd resultthaan , tF glossn si y (Tabl wax, e3) y coverine th f go neck hair d (Tablan y, nece4) k dominant(Table ar ) e5 , while short stra recessivs wi e (Tabl . These6) e character undee controse ar rth l of single genes. Waxy covering on the spike seems to be controlled by at least two genes with additive action (Table 7).

113 basie O nth segregationf so 0 generationF e th n si attenpn ,a s twa mad determino et e linkage relationships betwee traitne somth f seo under study observee Th . d segregation presentee sar . Hair9 tablen d i yan s8 neck is inherited independently of dwarfness and waxy neck covering is also inherited independently as shown by the close agreement between observe theoreticad dan l calculations assumin ratiga 9:3:3:1f oo . Large deviations of observed values from theoretical were found in two crosses involving hairy neck and waxy neck covering. These were considerably greater than would be expected on the basis of the ratio 9:3:3:1 (Table existanc10)e Th . linkagf eo e relationshipe th f so analyzed traits is consequently suspected. The recombination percentage was calculated by the method of Tmyinum likelihood and found to be 18.8% (Table 11). Chang et al. (1973) localized the gene for hairy neck, Hp_ chromosomn ,o least a crossoveR 0 et5 5 r units froe mth centromere resulte Th . thif so s study showed thagen e waxr tth efo y neck covering alss i o, locate,Hx same th e n chromodo sdistanca on t ea e of about 19 units (Figure 2).

2. Correlation Between Characters. Durin course gth developinf eo dwarga f tritical mutationy eb e ,on imnediately ask planw sho t height relate charactero st s determining yield. To clarify this question, correlations between plant height and yield components were studied. The correlation coefficients between character

pairs studied in the parents and the F-,, F2, BC,, BC2 generations are presented in table 12. Plant height showed significant correlations with grain yield per spike and 1,000 kernel weight in all generations, but was not significant for the parents. This may indicate that selection for short stem would decreasleaa o dt productivityn ei worts i t hi mentionint ,bu g that this correlatio largt could no ean s dnwa possibl brokee yb n during selection. Correlations that wer significant eno t were found between

plant height, numbe grainf ro spikr harvessd pe ean t inde F-,n , xi 2 ,F spikeled an 2 P t BC p , fertilit2 F - BC 2Thi2 ,P p sF mighn yi t indicate that selectio higr nfo h kernel numbe spikr rpe e would produc esignificana t increase in yield of the dwarf mutant. Among other characters studied, grain yiel spikr dpe e showed significant association with harvest index, number of grains per spike, number of grains per spikelet, and 1,000

2 generationsBC p kerneinterestins BC i , t 2 lI F . weigh p F o gt n ti

114 observe that among all the spike characters studied, only number of grains per spikelet showed highly significant correlation with weigh grainf to s per spike and the association was consistent over all four generations studied. Further, as expected, the number of grains per spikelet is highly positively correlated with the number of grains per spike. Selection for high spike fertility will improve kernel weight per spike. On the other hand, good fertility is positively correlated with harvest index. Therefore, selectio higr nfo h harvest index shoul effective db e in the improvement of grain yield in dwarf mutants. The other finding of interes thas twa t phenotypic correlations betwee pairl nal f so characters studied were not significant in the dwarf nutant. It is also interesf o t thaimportano ttw t component yieldf so , i.e. numbef ro grains per spike and 1,000 kernel weight, which are generally observed to be negatively correlated, were negatively but not significantly correlated. As these traits appeared to be inherited independently, simultaneous improvement in both these components could be expected. PATH COEFFICIENT ANALYSES Further informatio interrelationshipe th n no s amon charactere gth s studie obtaines dwa paty db h coefficient analyse phenotypif so c correlation coefficients. Grain yield was considered the resultant variable and culm length, spike length, harvest index, number of grains per spike, grains per spikelet 1,00d ,0an kernel weight causae ,th l variables patA . h diagram based on the phenotypic correlation coefficients is presented in figure 3, where P represents the direct effect and r denotes the phenotypic correlations between the characters involved in the system. Among all the spike characters, only one, namel numbee yth kernelf ro spikr spe d eha high positive direct effects on grain yield. This reveals an association of these two components while yield per spike was not influenced by the indirect effec othef to r component characters 1,00e 0Th . grain weight, which otherwis higd eha h positive association with grain t yieldno d ,di here show high direct effect and correlation. It appears to be due to some indirect effec culf to m length direce Th indirec.d tan t phenotypic effect othee eacth f s o r f ho character s were relativel resulte y Th low. s of this study indicate that selection for number of grains per spike woul more db e effectiv increasinn ei g grain yield than selectioe th r nfo other components of grain yield. Jain et al. (1973) have also reported the importanc graif eo n numbe grain ro n yiel dwarn di f wheat.

115 ACTIOE ŒN N Sinc knowledgr eou genf e o quit s ei actioe e ry limited n ni d ,an since rye and wheat genomes may interact in triticale, the research on gene actio hexaploin ni d tritical importans ei t both from scientifid can practical breeding points of view. Although such studies have been made in detail for wheat and barley, information on gene action in tritical vers ei y limited numbee th genetif s ro A . c factors conditioning a trait may increase in triticale, it seems reasonable to suppose that the number of interactions among factors will also increase. joine Baseth tn do scalin g test ,threa e parameter model proveo dt be satisfactor explaio yt genetie nth c differenc harvesr efo t index, indicating that epistasi involvet inheritance no th s s i n di thif eo s character (Table 13). Dominance effects appeared to be a more important factor contributing to genetic control for this character. Because of epistasis, the three parameter model was not sufficient to explain the genetic variatio other nfo r characters thir Fo .s reasonparametex si e ,th r model was used. Dominance and dominance x dominance epistasis contribute to the estimate planf so t height. Dominanc additivd ean additiveex , dominanc edominancx e epistasis effects rrpA=majoe th > r contributioo nt spike length. Additive, dominance and additive x dominance epistasis were important for grain yield per spike. Epistatic gene effects were large in magnitude and equally important as the additive effects. Inheritance of grain number has largely been governed by dominance and additiv edominancx e epistasis. Epistatic effects wer largf eo e magnitude relative to additive components. These findings suggest that selection for high, number of grains per spike would be more effective in later generations. The character, 1,000 kernel weight, was controlled not only by additive genes but also to a great extent by genes with dominanc negativd ean e dominanc edominancx e epistasis. This indicates duplicativa e typ epistasif eo thir sfo s character. These findings suggest that selectio higr nfo h 1,000 kernel dwarweighe th fn ti mutant effective e mighb t tno . Numbe grainf ro spikeler spe t were characterized by high, dominance variance with more than five times the additive x dominance and negative dominance x dominance epistasis. Dwarf mutants were used in our triticale breeding as a valuable initial material for the development of new short strawsd varieties resistan lodgingo tt breedinA . g program, usin shore gth t varieties

116 •was initially following e baseth n d o transe e th : dwarf ro f geneo st both hexaploid and octoploid triticales, and the improvement of the winter surviva dwarf lo f tritical crossiny eb g with some winter-hardy varieties, stach as AD 206 and AD 209.

Attempts are being made to compare the dwarfing genes with already identified gene n "Toi s m Thumb d Olsean " n dwarfs usine th g diallel method. In 1981, eight of the best dwarf lines were evaluate e Krakoth n i wd distric p triticalf Polando to t e Th . e dwarf, Tm-143, yielded 4.800 kg/ha, compared with 5.300 kg/ha for "Grana" wheat and 4.150 kg/ha for rye.

1. Chang, T.D. Kimber. ,G E.Rd ,an . Sears 1973. Genetic analysis of rye chromosomes added to wheat. 4th Int. Wheat Gen. Symp., Columbia, Missouri. 2. Grzesik 1980. ,H . Effec chemicaf to l mutagen variatioe th n so n of certain trait severan si l form wintef so r triticale. Hod. Eoslin. 2 Akl . Z . 4 Nas2 . .T 3. Mather, K. 1949. Biometrical genetics. Dover Publications Inc., London, England. Mather. J.Ld 4. an .. , K Jinks 1971. Biometrical genetics. Cornell Univ. Press., Ithaca, New York.

117 ObserveL BC d d numberan . f dwarBC so , F_ f e plantth n i s TABLE 1 generation of the triticale cross, Tm-100 x B-Î051.

Cross Progeny No. of plants in F2 , BC^, BC2 s-dw. tall short C dwarT f P 0.30- 7 4.1 9 1 9 5 3 6 8 Tin-10 2 F B-2050x 1 0.20 0.80- BCL 65 — — 16 1.060.70 0.70- — 0.1 — 6 4 9 4 3 BC2 0.50

TABLE2 Propose complementaro dtw y dominant gen inheritancee modeth r lfo f eo dwarfing in mutant ItarlOO. Phenotype genotype of parents Genotype of straw length in

2 BC ^ BC 2 F Un-lOO L F B-2051

senrL-dwarf . £ . £ J.J.4. . d ± ^ W?2

tall dididodo dididodn — - dldldldl w& short dldlD2D2

dwarf

118 TABLE 3: Observed numbers of glossy and waxy plants from the F generatio f threo n e triticale crosses.

I Plant . f Plants. No 'X No s 2 ,F Cross Glossy Waxy

6X1250 X 6X1274 281 208 73 0.172 0.90-0.60 6X1250 X 6X200 200 149 51 0.027 0.95 6X1250 X 6X1240 302 233 69 0.633 0.50-0.10

TABLE 4: Observed numbers of glossy and waxy neck plants recovere 2 dgeneratioF froe o triticalth m tw f o n e crosses

Cross No. Plants No. Plants, F0 'XT P Glossy Waxy 6X6T006 x 6X161 163 116 47 1.17 0.50-0.30 6X6T006 x 6T MI 123 89 31 0.38 0.50-0.30

TABL : 5 EObserve d number f hairo sd smooth:an y ; neck plants from th 2 generatioF e f threo n e triticale crosses

: Plant. No Plantsf . . Tc No s 2 ,F Cross Hairy Smooth 6X61006 x 6TA204 90 68 22 6X6T006 x 6T-E100 163 116 47 1.17 0.50-0.30 6X6T006 X 6T W 118 89 29

TABLE 6: Observed numbers of dwarf and tall plants in the F progenies of a triticale cross.

Cross No .Plants No. Plants, F0 *X? Tall Dwarf 6X6T006 x 6TMÏ 118 83 35 0.81 0.90-0.50

119 TABLE 7: Observed numbers of waxy and no waxy spike plants from the F £ generation of two triticale crosses.

Cross No. Plants No. C Plants1 2 ,F P Waxy No Waxy 15:1 Spike Spike 6X932 x 6X135 1 88 82 6 6X6T00 x 6X166 1 188 177 11 0.09 0.90-0.50

TABL : 8 ELinkag e relationships between dwarf stra haird wan y neck charactergeneratio_ F e th a triticaln i f so n e cross. 2 Cross No. Plant Plants. No s 2 ,F •x P Tall Tall Dwarf Dwarf Hairy Smooth Hairy Smooth

6T6T x 61 m 188 64 19 25 10 2.160.70-0.55 0 (theor.6 )6 22 22 7

TABLE 9: Linkage relationships between dwarf straw and waxy neck character F generatio e th n a i triticals f o n e cross.

Cross No.Plant Plants. No s, ,F Tall Tall Dwarf Dwarf Hairy Smooth Hairy Smooth 6X9825 x 6TM 180 116 22 37 5 10.0 0.02-0.01 1 1 4 3 4 3 (theor. 1 10 )

120 TABL : Linkag10 E e relationships between hairy necwaxd an ky neck character ~ generatioF e o triticalth tw n i sf o n e crosses.

2 Plan. No ts Gross Observe. dNo of F2 Plants a P Hairy Hairy Smooth Smooth Waxy No Waxy Waxy No Waxy

I 6X6T00M 6 x 6 123 77 14 12 20 27.71 <0.001 (theor.) 69 23 23 8 6X5T00 x 66XL8 1 163 94 22 22 25 27.06 <0.001 (theor.) 92 31 31 10

TABI£ 11 Percen recombinatiof to n between hair waxd yan y nec maximuy kb m likelihood. Cross % of recombination Standard error 6X6T006 x 6T MÎ 24.0 + 2.92 6X5T006 x 6T161 13.7 ±1.31 Average 18.8%

121 TABLE 12 Correlation coefficients between sane characters

Spike Grain Harvest Grain# / 1 Grain/ 1,000 Length Yield/ Index Spike Spikelet Kernel Spike Weight Straw Pj -0.05 0.11 0.02 0.02 0.26+ 0.04 Length 2 P 0.24+ -0.17 -0.36++ -0.08 -0.01 -0.13 Fj 0.14 0.44++ 0.13 -0.13 0.20 0.26+

2 ? -0.08 0.36++ -0.15 -0.07 -0.07 0.34++

BC1 0.15 0.42++ 0.20 0.19 0.36++ 0.33++

BC2 -0.23++ 0.28++ -0.26++ 0.03 -0.12 0.61++ 0.01 0.24 Spike- Pl 0.13 -0.02 -0.14 Length 0.32++ 0.05 P2 0.09 0.20 -0.01 -0.02 0.07 Fl 0.15 -0.01 0.20 -0.13 F2 0.31++ 0.05 0.34++ 0.19 BC. 0.40++ -0.09 0.26+ 0.00 0.20

BC2 0.45++ 0.27++ 0.28++ 0.45++ -0.11 0.01 -0.11 -0.04 0.01 Grain Pl Yield 0.02 P2 0.03 -0.04 0.16 0.34++ 0.54++ 0.29+ Fl 0.14 0.49++ 0.47++ 0.56++ 0.36++ F2 0.41++ 0.43++ 0.46++ 0.53++ BC1 BC2 0.40++ 0.40++ 0.65++ 0.52++ 0.32++ -0.15 0.02 Harvest Pl Index 0.07 0.44++ 0.33++ P2 0.06 0.12 0.27 Fl 0.30++ 0.48++ -0.04 F2 0.38+ 0.55++ 0.14 BC1 BC, 0.12 0.43++ 0.09 f Graino f s P 0.09 -0.01 per spike l P2 0.24+ -0.03 Fl 0.08 -0.08 F2 0.67++ 0.02 BC1 0.55++ 0.10 BC2 0.46+4- -0.01

1 of Grains P 0.04 per spikelet l P2 -0.10 Fl 0.12 F2 0.03 BC1 -0.02 BC, -0.06

122 TABIE 13 Estimates of gene effects for various characters in triticale cross.

Straw Spike Grain Harvest # Grains/ # Grains/ 1,000 Length Length Yield/ Index Spike Spikelet Kernel Spike Weight

3 Parameter 94.58** 43.42** 73.54** 3.65 65.04** 55.09** 35.42** hfodel X2

Paranete6 m r100. 9 +0.26 1 7 .5 40.52 3.6 40.03 0.5 40.01 67.3 0 40.61. 9 +0.01 51.2 40.48 îfcdel a 35.5 40.27 .20 40.08 1.0 40.03 0.1 40.0 9 0 40.70. 8. 15 40.75 6.5 40.43 d 32.1 ±3.53 .43 6 40.0410. .380 0.3 40.06 13.0 +1.21 0.440.-21 12.6 +2.27 2 - — aa .8 40.51 — — — ad — -0.7 40.36 -1.0 40.27 -23.0 +3.89 -0.440.09 — dd -34.0 +3.59 .23 40.92 -0.3 40.07 -D.I +2.24

** significant beyond P- 0.01

Figur e1 Straw 2 generationlengtBC p h BC distributio , s2 F p F , 2 nP curvep P f so of Thi-100 x B-2051 cross.

PERCENT OF PLANTS

mo i3o no no 160

2. ____ _ P, B-2051 chromosomf o p FigurNa showineR 2 e5 presunee gth d positio genef n o wax r sfo y neck covering, Wx and hairy neck, Hp.

NSc

50.0

Figure 3 phenotypic diagram of yield and selected factors in dwarf triticale cross.

124 GENETIC AND AGRONOMIC EVALUATION OF INDUCED SEMIDWARF MUTANT RICEF SO *

J.N. RUTGER Agronomy Department, Agricultural Research Service, Universit f Californiayo DepartmenS U , Agriculturef o t , Davis, California, United State Americf so a

Abstract

Induced semidwarf mutants have played an important role in California's rapid shift from nearl tall yal l rice varietie 197n si 8 to nearl semidwarl yal f varietie presentt sa 198n I . 1 over half fo the California rice area was planted with semidwarf varieties carrying the induced mutant semldwarflng gene sd,, whil othee th muc rf ho hal f JL was planted to a variety deriving its semi dwarfism from 1RS. The sd .mutant is allelic to the major semidwarfing gene in DGWG and IR8. Current objectives are to determine the inheritance of new semidwarf mutants» including a1leiism tests wit hevaluato t sd. d agronomie ,an eth c potential of nonallelic sources and of doubledwarfs. To date semidwarf mutants from 10 varieties have been partially or completely evaluated. At least three nonallelic semidwarfing genes, sd , sd., and sd., have i ~~ i —~^~~ » i been described. Rather than attempt to determine all possible allelic relationships of new mutants, crosses are being made only to the

x . j ,referenc e sd, source, since sd. still seems to be the most productive Isemidwarfing gene source. However, nonallelic semidwarf mutante th n si varieties M5 and Labelle may be useful if genetic vulnerability from widespread usage of the sd. source becomes a problem. ""

* Cooperative investigation USDA-ARSy sb Californie th ; a Co-operative Rice Research Foundation; and the California Agricultural Experiment Station.

125 INTRODUCTION rice Virtuallth e f areo Californin l ai yal plantew no s high-o ai dt * yielding semidwarf rice varieties, a changeover which began in 1978, whei} about 90% of the area was still in tall varieties. In 1981 an estimated 54Z of the rice area was planted with semidwarf varieties carrying the induced mutant semidwarfing gen eplantes wa sd- 2 d35 , wit varietha y which received its semidwarfing gene from 1RS, and the remainder was planted to tall varieties [1]. The percentage of tall varieties is expecte declino t d e even furthe 1982n ri . The sd mutant was induced by state and federal personnel at Davis, . California, in 1971 [2], and was released in 1976 as Calrose 76 [3], the first semidwarf variet Californian yi time mutane th th e y B t. .variety releaseds wa , Rutge Petersod predicted ran ha ] n[4 d tha woult a ti e db valuable semidwarf donor in cross-breeding programs. This prediction was realized when the California Co-operative Rice Research Foundation very quickly develope semidware th d f variet 197n i 7 7yM [5] whed 4 ,an nth Davis researchers took the lead in development of the semidwarf variety M-10 197n 1i 9 (Figur [6]) e1 Californi e ,Th a Co-operative Rice Research Foundation subsequently used the sd, gene source to develop four more •~—1 varieties through cross-breeding [7, 8, 9, 10], and released another induced semidwarf mutant directl variete th s ya y M-401 [11] othee .Th r two publicly developed semidwarf varietie Californian si M-201d an 9 ,,M derive their semidwarf ism from IR8 [12, 13]. Semidwarf varieties in California generally yield about 15% more than the tall varieties they replace werd ,integraan n e a l recore factoth n dri average yielf do 8.07 metric tons/ hectare achieved on California's 245,000 hectares of rice in 1981.

126 inducee Th d mutan allelits majoe i gen th . ro esd t c gen semir efo - DGW n dwar1RSd i principaGA an m . f is l advantag inducee th f eo d mutant gene is that it is in an adapted cold-tolerant variety and therefore provided a quick means of obtaining semidwarfism in California. Of especial valu California'n ei s water-seeded rice facculture th t s ewa that semidwarf lines with seedling vigor equal to the tall parent could be recovered from crosses [14]. Concurrent with the adoption of the sd. source, additional semi- dwarf mutants have been induced, some of which are nonallelic to sd.. ^™*X The nonallelic sources are of interest for reducing potential genetic vulnerabilit widespreae th o t e dydu usagsingla f eo e semidwarfing source. Thus the current objectives of the induced mutation work are to hybridize new semidwarfing sources with the sd- source in order to * identify useful nonallelic semidwarfing evaluatgeneso t d e ,an eth agronomic potential of the nonallelic sources and the various doubledwarfs resulting from recombination of the sd. and the nonallelic *"^~l sources presene Th . t report summarizes progress towards these objectives.

MATERIALS AND METHODS As additional induced semidwarf mutants are accumulated, a program of hybridizatio d referencs e th o nt e sourc initiateds ei , simulta- """"I neously with preliminary agronomic evaluation of the induced mutant. hybridizatioe th n I n program marke,a r genglabrour efo s hulld san leaves (gl uses )i eliminato dt e selfscompares i s .F' dHeighe th f to to both semidwarf parents. Sinc plant. F eavailablew e onlsfe ar ya , and usuall growe y ar greenhous n ni e conditions whic limiy hma t height expression principae ,th l datdetermininr afo g allelis collectee mar d in the F- and F. generations.

127 agronomie Ith n c evaluations mutante th , e yield-testear s n di replicated large plots (about 2.5 x 6 meters). Some of the tests are in the multi-location yield trials conducted by the California Cooperative

Extension Service Californith d an e a Co-operative Rice Research Founda-

tion; others may be only single location tests conducted by one or more of the three agencies engaged in public rice research in California

(state « California Agricultural Experiment Station; federal » U.S.

Departmen f Agricultureo t , Agricultural Research Service; industry«

California Co-operative Rice Research Foundation, Inc.).

RESULT DISCUSSIOD AN S N

To date inheritance and/or agronomic data hav ee bein beear r gno

obtaine semidwarn do f mutants fro varieties0 m1 agronomid an , c data have

been obtained on two recombinant doubledwarfs (Table 1). The most extensively investigated mutants are the nonallelic sources from Calrose:

. thlocusd e sx cross-bre si presen s it Calrosn d i t dan derivativ6 7 e e

varieties, the sd,, locus in D66, and the sd, locus in D24. Genetic

studies have show , locunsd thas e allelii smajoe th t th ro ct sem i dwarf-

ing gene in 1RS and DGWG. Thus in F£. generations of crosses between sd.J. and the latter types no truly tall recombinants have been recovered, although considerable-variation existsemidwarf. F heighe n si th f to s [15, 16] crosse.n I s with tall varieties recessive ,th mutan. esd t gene shows rather definitive semidwarf versus tall segregation [15, 16]» On the other hand, the DGWG semidwarfing source shows less discrete variability, which is usually attributed to the presence of a single major gene plus several modifiers. The major gene-plus-modifier nature of the DGWG source would explain the variation in semidwarf height that is see crossen ni s betwee inducee nth d DGWd mutanan G . sourcestsd .

128 Genetic studies amon sd.e mutantth g, , sd sd^ d ,san from Calrose have shown that these three gene independentle sar y inherited [15, 16]. Typically, F-t's are tall, and 9 tall:6 semidwarf:! doubledwarf ratios are observed in the F- (Table 1) . However, neither the sd,. nor the sd, source bees sha agronomicalls n a source. y sd sd,e usefue Th ,.th s la source reduces height only 15 cm and thus is still somewhat lodging- susceptibl higt ea h fertility level d reduces(s s height , aboucm 0 t3 a more desirable reduction). The sd. source also reduces height only additionan a s ha d lan pleiotropi, cm 5 1 % reductioc20 effeca r n ntfo i

seed size. Doubledwarf s carrying sd- + sd__, and sd. + sd., have been too short (about 65-75 cm) and are not as agronomically productive as semidwar, thesd f [17 ]thire Th (Tabld . doubledwarf, e1) , sd + L ,£c s createdwa sinct heigh,d s bu semidwars eit e abou s samtth e wa tth s ea f (85-9beet no n 5 s pursued cm)ha t ,i . The two semidwarfs from M5, CI 11045 and CI 11046, are especially interesting because both are nonallelic to sd, and, except for a tendenc shoo yt w discolored hull harvestt sa phenotypicalle ,ar y sourc- identicasd e eth [18]o lt . Althoug h"raw5 M neithee "th f ro semidwarf bees sha n more productive than their tall parent (and thus by inference are less productive than sd- sources), neither has been evaluated for yield potential after crossing to other genotypes. Thus it might still be possible to "clean up" the M5 semidwarfs and obtain recombinant sourceproductivs - sa sd e th . sourc- s eShoula sd e eth d ever prove genetically vulnerable semidwarf5 M e ,th s will certainly receive greater attention« The two narrow leaf semidwarf mutants, CI 11049 and CI 11050, have been of interest because they produce over three-fourths of normal semidwarf yields with only hal mucs fa h leaf blade area [19]. Thus these lines seem to be more efficient at trapping sunlight energy. It

129 is postulated that their reduced yield may be due to being too short, since the narrow leaf semidwarfs are 10-15 on shorter than sd. . Thus attempts are underway to obtain narrow leaf recombinants with 85-95 cm heigh hopen ti raisinf so g yield competitiva o st e level dato T . e this effort has not been successful, because the semidwarfing gene in these lines is invariably associated with narrow leaves. Shore Th t Labelle mutan dato t enonalleliseemt e b bu o st . sd o ct the presence of doubledwarf recombinants has not been confirmed (Table . Perhap1) doubledwarfe sth s froShore mth t Labelle/sd, crosses were too shor survivo deee t th p n wateei r use Californin di a (10-15 cm). hopes 198f i o t d 2di en thae Btyth additional progeny tests will resolve the apparent absence of doubledwarfs. The most interesting featurShore th tf eo Labell e mutan thas ti representt ti snonallelia c semidwar lona n gfi grain background. Short Labelle equalle yiele dth d of its tall parent in one test in Arkansas in 1981 [20], but when averaged over four tests it was noticeably lower yielding than Labelle (Tabl . Attempte1) "cleao st Shor" nup t Labell hybridiziny eb t gi wit parens hit othe d tan r adapted long grain varietie underwaye sar . Four new send.dwarf mutants were recently obtained from US coopérators: Irradiated Labelle Dwar Irradiated fan d Brazos Dwarf from i C. N. Bo11ich, USDÂ-ARS, Beaumont, Texas; Irradiated CI 11032 Dwarf (four selections) Tseng . froT . nS , California Co-operative Rice Research} Foundation, Inc., Biggs, California; and the newly-released variety M-401 [11], All were hybridized with the reference sd- source. Height beins i segregatio gs F' evaluate e 198e th th f 2nn o di nursery .

130 REFERENCES [I] Brandon, D. M., Carnahan, H. L., Rutger, J. N., Tseng, S. T., Johnson, C. W., Williams, J. F., Wick, C. M., Canevari, W. M., Scardaci Spécia, Hill, E. C. . ,. J ,l S Pub. 3271, Divisiof no Agric. Sei., Univ Califf . .o pp 9 .3 [2] Rutger, J. N., Peterson, M. L., Hu, C. H., Lehman, W. F., Crop Sei. 16(1976)631. [3] Rutger, J. N., Peterson, M. L., Hu, C. H., Crop Sei. 17(1977)978. [4] Rutger, J. N., Peterson, M. L., Calif. Agric. 30(6)(1976)4. [5] Carnahan, H. L., Johnson, C. W., Tseng, S. T., Crop Sei. 18(1978) 356. [6] Rutger, J. N., Peterson, M. L*, Carnahan, H. L., Brandon, 0. M., Crop Sei. 19(1979)929. ] Carnahan[7 Johnson, TsengBrandonL. , , . W. T. , H . . M. ,,C S . ,D Crop Sei. ^0(1980)551. ] Johnson[8 Carnahan, W. TsengBrandon, , . ,C L. T. , . . M. , H S . ,D Crop Sei. .20(1980)551. ] Johnson[9 Carnahan, CroW. , TsengHill, , . ,E. C p L. T. . ,. . J ,, H S Sei. 21(1981)986. [10] Carnahan Johnson, TsengRutgerL. , , , . W. T. , H N. . . ,,C S . , J Crop Sei. 21(1981)985. [II] Carnahan, H. L., Johnson, C. W., Tseng, S. T., Brandon, D. H., Crop Sei. _21(1981)986. [12] Carnahan Johnson, TsengMastenbroekL. , , . T. W. , H . . ,S C , J. . ,J Crop Sei. 18(1978)357. [13] Carnahan, H. L., Johnson, C. W., Tseng, S. T., Hill, J. E., Crop Sei. 22(1982) in press.

[14] McKenzie Rutger , Peterson, S. N. Cro . , ,. K , J L. p . ,SeiM . 20(1980) 169.

131 [15Î Foster, K. W., Rutger, J. H., Genetics 88(1978)559. [16] Mackill, D. J., Rutger, J. N., J. Hered. _7JX1979)299.

[17] Rutger Foster , McKenzie, N. W. . , . J ,MacKill K S. . , ,K J. . ,D t Cro, H. p . SeiC . , PetersonHu ^9(1979)299 , L. . ,M . [18] Rutger Carnahan, N. Johnson, . ,J CroL. , . W. , pH . ,SeiC . 22(1982) 164. [19] Travis, R. L., personal communication (1982). [20] McKenzie, K. S., Lee, F. N., Wells, B. R., Arkansas Farm Research (Jan.-Feb. 1982)3.

Us f Induceeo d Semidwarf Mutant Ricn si e Breeding

1948 ColroM

1RS 1968

J TVso 1976 15 J 1977

1979

1980

1981 JM-302J |Colmoehi-202|

1982

Figure 1. Use of induced semidwarf mutants, and the IR8 semidwarfing source developinn ,i g current public short medium-graid -an n rice varieties in California. The eight semidwarf varieties carrying an induced mutant gensemidwarfisr efo boxen i e s mar wit h thick lines; the two semidwarf varieties with the 1RS source of semidwarfism are in boxes with thin lines. The parent not shown in each cross was one of several adapted tall California japonica varieties.

132 Tabl . eInheritanc1 e datagronomid aan e potentia inducef lo d semidwarf mutan doübledward tan f recombinant rice lines,

F. segregation ratios of crosses , frosd mo t Calros 6 7 e Yield Parent Semidwarf P 9:6:1 Genotype variety allele Tall Semidwarf Doubledwarf or Z of talld s f o Z (115-12 ) (85-9 5) (65-7cm ) 5cm 9:3:3:5cm 1 kg/ha check check* Reference CI 11033 (D660 1 ) 0 7 Calrose 8 10 . sd 0.75-0.90 7170 78 [15,17] CI 11034 (D24) Calrose sd^, 583 363 47 0.05-0.10 7870 97 [16,17] CI 11035 (D380 ) l Al Colusa 0 £ s 7620 95 [17] CI 11045 (S6190-96) M5 sd,#sd ** 60 44 7 0.90-0.90 7880 96 [18] ; " " X CI 11046 (S6190-110) 4 M5 3 3 7 6 sdjfedj 0.30-0.505 9 7830 118] CI 11047 (S8158-39) Maxwell unknown 0 10 7680 [18] CI 11049 (narrow leaf) Calrose sd,j*scL 59 15 normal leaf 1 0.10-0.20 7720 84 [18] OJ 16 narrow leaf (9:3:3:1) CI 11050 (S6193-3; narrow leaf) Tsuru Mai unknown 7390 84 [18]

Short Labelle 0 Labelle 1 13 3 22 sd9fod <0.005 6100 87 [20]

CI 11036 (0)1) Calrose 76/D66 -l d 7720 85 [17] M1 2 -2 SD24/Calros6 7 e CS-M3/D24//Calros6 7 e sd,+sd, 8490 85 [16] —1 —4 M-401 Terso •a, 1 2 11 9270 104 [11] Irrad. Labelle dwarf Labelle — ? y F2 in field in 1982 Irr ad. Brazos dwarf Brazos sd. 1

Irrad I 1103C . 2 dwarf CI 11032 S<^7 J

*Semidwarf check varieties carrying the induced mutant sd, allele generally yield 15% more than tall check varieties. **Bd.tsd.—I ——L means that —sdg, is nonallelic to —sdi, but its relationship to other —sd alleles is unknown. EVALUATION AND GENETIC ANALYSIS OF SEMI-DWARF MUTANTS IN RICE (Oryza saliva L.) *

M.A. AW AN, A.A. CHEEMA, G.R. TAHIR Mutation Breeding Division, Nuclear Institute for Agriculture and Biology, Faisalabad, Pakistan

Abstract

Four semi-dwp.rf mutants namely DM16-5-1, DM16-?-?, DM-? and DM107-4 were derived frolocae mth l tall hasmati cultiver. The mode of reduction of internode length was studied in DM107-4. The reduction in culm length was due to a corresponding "hut disproportionate reduction in all the intornodes. It was inferred that reduction in internode length contributes more towards redxictio heighn ni compares ta reductioe th o t d n in the total number of intornodes. The effect of semi-dwarfism on some yield components (panicle characters) was studied in two semi-dwarf mutants viz, DN16-5- DM107-d 1*n 4 compare Pasmato dt i ^70 .marginaA l reductio panicle th n i ne axis, primary tranche panicler spe , secondary "branche primarr spe y branc panicler hpe , spikelets borne on secondary branches and total number of spikelets «. paniclr pe observes ewa DM16-5-1n di , whereas ,significana t reductio thesf no e character observes swa DF107-4n i d . Evaluation of the semi-dwarf mutants with respect to grain yiel harvesd dan t index showe mutante d th thal stal possess high yield potential with higher harvest index values compare parene th o tdt cultiver.Genetic analysi planr sfo t dialle4 heighx 4 ln ti involvin g semi-dwarf mutants revealed that mutant DM107-4 carries mainly recessive alleles while mutant DM16-5-1 showed some dominance effects as assessed through the estimates of genetic components of variation and Vr,Wr grarh analysis.The semi-dwarf mutants have good potential for use as parents in cross-breeding programmes.

* Research finance pardn i USDy tb A under Co-op. Agri. Res. Grant Programme (PL 480, FG.Pa-287) and supported by IAEA under Research Contract No. 3118/RB.

135 INTRODUCTION

Rice occupies a vital position in the economy of Pakistan first because it serves as a source of majorite th foor populatiof fo dyo rice th e n i n prcwinp: areas and second, it is one of the major earners of foreign exchange.The climatic conditione th n si Provinces of Punjab and Sind are particularly suitable for the cultivation of pood duality rice. In Punjab, the Jhon Easmatd an a i varietiess e formeit ,th r rfo early maturity and the latter for its excellent cooking ouality regaine predominane th d t varietie 196o t p 7su whereas, vnrieties Ja,1aKanp-nd an 7 occupie7 i7 ? i e th d top positio Sindn ni . Although a considerable area in these four provinces remained under rice cultivation unti late th le sixties, the productio verS nWP y low, mainly^because us e th f eo of tall and weak stemmed rice varieties which are prone to lodginr.In 19671 a semi-dwarf strain namely IR-8-288-3 (Pet eDGWGx ) develope IRRI,wat a d s introduced an d tested. It yielded on average 5810/kg/ha as compared to 2305/-ker/ha of the local variety Jhona 349.In view of its high yield potential, this strain was aprroved in commerciaa 196s a 9 l variety unde name IRRI-PAKf rth eo . However, this variety soon lost its popularity due to its chalky grain and poor milling recovery. Later on, another strain IR-6-156-2-1(Siam 29 x DGWG) having better grain type than IRRI-PA s approveKwa conunera s da - cipl variety under the name IRRI-6.Although the introduction of the semi-dwarf varieties resulted in a sub- s-t-flntifll inor*»pse in rice production (Pig.1) these favoue th consumerf n ro wi t varietieye st becausno o sd e of their inferior grain and ouality characters. Moreover, these varieties derive their semi-dwarf plant type from a single dwarfing source "Deo-Geo-Woo-Gen" y exhibi(DGWGma d )an t common defects like susceptibility to diseases and insect pests. In Pakistan, varieties having the (DGWG) gene in their backgroun w becominno e ar dg widely susceptibl e whiteth o t -e backed plant hopper and bunt disease. One possible solution for these problems would be to develop and locate alternate sources of

136 semi-dwarfness in the local, well-adapted rice varieties. Efforts to develop semi-dwarf varieties having acceptable quality characteristics through conventional breeding methods utilizing the only available dwarfing source i.e. Dee-Geo-Woo-Gen have not succeeded mainly becauspooe th r f qualito e y associated wite semith h - dwarfing gene. Mutation breeding is an alternate approach to avoid such linkages to obtain the desired trait without resorting to a crossing programme n ricI .e induced semi-dwar d non-lodginan f g mutants have been reporte y severab d l workers.(3,17,19). Realisin e potentiath g l rol f induceo e d mutatione th r fo s improvement of crop plants, an on-going breeding programme was established at NIAB to develop high yielding models of basmati type rice. The programme deals with i) induction of semi-dwarf mutants e adapteth n i d basmati backgroun ) evaluatioii d f induceo n d mutants capable of direct release as varieties iii) use of induced mutant genes in genetic and physiological studies and iv) to apply this information to develop more productive basmati varieties. This report review evaluatioe s th wor n o k genetid an n c analysis of some of the semi-dwarf mutants of basmati rice.

Method Materiald an s s

To study the mode of internode length reduction, Basmati 370 (plant height, 177cm) and its semi-dwarf mutant DM107-4 (100cm) were grown under comparable environmental conditions. At maturity the main tillers of 21 plants were randomly selected for recording data on i) total length of culm (excluding panicle) ii) length of each internode and iii) number of developed internodes ( 0.2 cm in length). o studT e effecth y f semidwarfo t panicln so e characterse th , mutants along witparene th h t variety werm c e 0 grow2 x rown i n0 2 s apart, in a randomized complete design with 3 replications. At maturity five competitive plants from each entry per replication were randomly selected and data with respect to yield components viz. length of panicle axis, number of primary branches per panicle, total length of secondary branches, number of spikelets borne on secondary branche d totaan s l numbe f spikeleto r paniclr pe s e were recorded. e datTh a were statistically analysed. For determining grain yield and harvest index the four semi-dwarf mutants, DM16-5-1, DM16-5-2, DM- DM107-4d 2an , along witparene th h t viz. Basmat 0 weri37 e growrandomizea n i n d complete block design with three replications (Plot size 2.74 x 4,57 m) during 1981. Observations on grain yield and biological yield were recorded and harvest inde s computedxwa . A renetic analysi semi-dwaro tw f so f mutants swa

made emplqjanp a 4 x 4 dial! el cross involvinp the semi-dvprf mutents DM16-5-1,DM107-4 and Bas^ati *70 (tal latd lan e maturing variety Kashmid )an r Easmati a ta3( enrld 1an y maturing: variety which originated as a mutnnt from Basmati ??0). The resulting P hyhrids

alonpr with the correspondin* parents were prown 1 in a randomized complete block desicm with J> replications.

137 entry was represented hy a ?.P meter long; row pland an plan o tt w ro t o spacint w witro 20cmf ga ho , at maturity, data on plant heip-ht were recorded on 5 plants from each row.The length of the tallest culm panicle th f o e p constitutefroti me th Vas ~ t< e d plant height.The genetic parameters were estimatea d an d Vr,Wr p-raph analysis was carried out(4~6). In addition o to the t test, which tests the overall assumptions of diallel analysis, repression analysis was performed (4) to detprmine the adeouacy of the additive dominance model.

RESTTLT DISCUSSIOND SAN S

rCDE CF REDTTCTICN 07 INTERNCDE LENGTH IN SETI-DVARF MUTANT

e mod Th reductiof eo internodf no e lenarfcs wa h studie semi-dwara n i d f mutan Easmatf to i 370. D?.ta on culm and intrmode lenp-ths compared, to Pasmati 370 ard sen»n-dvr»rf Ttrtant 0^*107- e presente*sr Tnhln i d , e"1 A maximum of 7 internod.es were recorded in Basmati 370 and 6 in the semi-dwarf mutant.The intrmodes were warVe dhase.Io t frop tc m n :the semi-dwarf routanta ^7.7^- reductio culn ni m length (excluding panicle) occurre compares a dparent.The th o t d e semi-dwarf mutan onld ha ty three elonp;ated(>1 interaode) 0cm t sa the top as compared to six in Basmati 370. Moreover, the semi-dwarf mutan thred ha t e short internodes, while d onlBasmatha y 0 onei37 . In the mutant, the mean length is 75 cm as against 145 in Basmati 370, showing a reduction of 69 cm. This reduction in culm length e correspondine mutanresule oth th th f f s o i t t disproportionatbu g e reduction in all the internodes. The maximum reduction was in 14(15.? cm) raimiue an(4.2 I th d n )i m cm). a Simila r fo ? rI reductiond an ^ 1 n i s semi-dwarf rice-mutant already have been reported. (15). The mean number of internodes was 6.9 and 5.3 in Basmati 370 semi-dware anth d f mutant respectively relative ,th e reduction i n the numbe f internodeo r mutane th 23.2s r i t fo s % compare 47.7e th o %t d reductio culn i n m length. This suggests that reductio n internodi n e length contributes more to height reduction than reduction in the number of internodes. e argueThereforb n dca t thamutatee i e th t d gene(s) which drastically reduces internode length semi-dwarfn i s s have (a) pleiotropic effects. Similar results have been reported by many workers (7,10,11).

138 Effec f Semi-Dwarfiso t n sommo e Yield Components

The effects of semi-dwarfism on panicle characters were investigate semi-dwaro tw e th n fi d mutants, DM16-5- d DM107-4an 1 . These mutants are respectively 207» and 40% shorter in height than e Basmatth i 370 marginaA . l reductio e paniclth n i n e axis, number of primary and secondary branches per panicle, spikelets borne on secondary brances and total spikelets per panicle as observed for DM16-5-1 compared to Basmati 370. (Table II). All of these characters were significantly reduce n DM107-4i e dmea th nt lengtbu , f o h primary branches per panicle was comparable to the parent cultivar. A significant reduction in the total length of secondary branches of both the mutants as compared to Basmati 370 was noticed. The coefficient of variation (C.V. n DM16-5-i ) highes wa 1 r relativ o Basmatt e 0 37 i l focharacteral r s except numbe f primaro r y branche r paniclpe s d an e total spikelets per panicle. For these a lower C.V. value was observed and in the case of DM107-4, the C.V. for all characters was lower than for the parent variety. All changes observed in the yield components (mainly panicle characters) were in the direction of the plant height change, i.e. reductio e planth n ti n e mutantheighth s associatef o twa s d with reductio e yielth dn i n components (panicle characters), although the degree of change varied from one mutant to the other and from one character to the other for the same mutant. The possible basi r sucfo s h modifications coul e pleioteropib d c effecte th f o s plant height locus. These resultn agreemeni e ar s t with thosf o e several other workers (7,13).

Grain Yield and Harvest index of Semi-Dwarf Mutants.

The high yielding semi-dwarf varietie f rico s e generally have a better harvest index. Harvest index is considered to be a useful selection criterion in modern cereal breeding programmes. Improved ahrvest index represents increased physiological capacity to mobilize photosynthat translatd an e t ei int o orpans bavin? economic value. Studies pertainin breedino gt r behavioud an r preliminary évaluation(yield and ouality) of the four mutants, DM16-3-1, DM16-?-?, DM-? and DM107-4 were made in the earlier penerations(?). Results presented in table III show that all the mutants pave a hipher crain yield and had higher harvest inder values thsn the parent variety .Maximum yield was obtained from DM-? whereor,DI;!16-5-<1 had the hisrher harvest index .The hipher graine yielb n dca attriV"ted to the increased tillerinp ability and non-lodrinp habit of these mutants.These results show thae shorth t t stature mutant more ar s e efficient in partitioninr the r-hotosynthate for the

139 development rf grain. £emidwarf mutants with higher harvest index values than parent varieties have .been reported (18). Cur results pl.°o provide evidence that a 40?* reduction in height may not adversely affect the grain yield n Bap^ati i rice, however r evefo , n more productive models of the basmati plant, selection can be made for variants wit increasen a h d numbe f spikeleto r s per panicle t I ma. mentionee yb d here thae th t approach to increased yield via increased grain volume weipbt in bprmsti rice may not be feasible, as it • may drastically affect the ouality and fineness of the grain (1).

GENETIC ANALYSIS

The analysis of variance( treatment means) among the parents and their hybrids showed highly significant di erpnces(Tahlff componente Th . ) variatioeIV f so f no the diallel cross data were estimated using the Jinks- Haymar method of analysis and the pertinent ratios are presented in Table V. All the components viz, D, F, BL , p f h wer d Hepn p highly significant, except environmental comnonpn whic, tE non-sienificants hwa .slighA t over- dominance with additive effect (D

ficant values of D,H^ and F?) was observed, the average frennenc positivf yo negativd ean e allelen si the parents(Hp/4H,j) indicatet no ds wa tha ^ tH significantly different from H«. Plant height in these crosses seems to be controlled by two groups of genes

The vflriance(Vr) and convariance(Wr) graph analysis for plant height is shown in Fig. 2. The semi- dwarf mutant DF107-4-, having recessive gene r planfo s t height falls farthest from the origin while the mutant DM16-5-1 which is ?C# less tall compared Basmat o t s slightli 0 37 i y abov positioe th ee th f no tall varieties viz.Basmati .370 and Kashmir Basmati whic e nea ar e originh th r . Thus DM16-5-1 possesses(a low^r proportion) of dominant alleles than Kashmir 140 BaPmpti and Basm^ti 370. It also may possess recessive alleles "but, in far lower proportion than to DM107-4. Genetic] studies on r>lant height in rice have "been made by several workers.WhiTe studying diallel crosses "between semi-dwarf rice varieties differing in growth period, overdondnance for plant height and •partial dominance for number of days to heading were found(14).Dominance of tallnepp already has "been reported (ft).Genetic Studies With induced rice mutants also have revealed that dwarfnes s controlle?wa recessivy d"b e 6renes(Q,t?,16) semi-dwarfise .Th mutante th f o ms include presene th n i dt study alse s founb owa o t d controlle recessivy db e eenes heritabilite .Th y value of P.4-? for plant height indicates pood potential for semi-dwarf o tbe eus f mutant parents sa crossn si - breeding programme.

ACKNOWLEDGEMENTS

The authors feel highly indebte Dr.S.H.tfo t d . Nanvi,Director, NTAB providinr ,fo g facilitier sfo the research work.

REFERENCES

) AWAN,K.A.(i , CHEEMA,A.A. Relationship amonp; test weight,plant heipb heighd tan t components in rice Cryza sativa I. Paper -presented at the National seminar on ^ice Research and Production, June 17-19(1981), Islamabad. (?) AWAN,M.A., ATmD,MAQBCCL, CHEEMA,A.A. Evaluation of short Ptnture mutant r Basmatf so fo 0 i37 yield and grain Quality characteristics.Pak.J.Sci. Ind.Res.(198?)(Accepted for publieation). (3) FUTSTTHARA,Y. Breeding of a new rice variety "Redmei y tramm"b y irradiation.Gammra a a field syrnp.Ho.;7(1968. )87 ) HAYMAN,B.I(4 theore . Th analysi d yan diallef so l crosses. Genetics; .22(1954) 789. ) FAYffAN,B.-I(5 . Intrraction, heterosi dialled san l crosses. Genetics;4?(1Q57)336. (6) JINKS, J.L, . HAYMAN,E.I. The analysis of diallel crosses»Maize Genetic Crop.Newsletter;?? (1953) 48. ) KAWAI,T.(7 , NARAHARI,P. Patter reductiof no f no internode length d chanp-esan f somo s e other characters in short-culm mutants in rice.The Ind.J.Gen. and PI.Breedinpr. I L C.C ) "(8 Diallel analysi compos yielit f so d - dan nent trait rice(Cryzn si a sativ ) J.Ap;riaL. . Assoc.China ,,92(1975. )41 ) MACKHL,D.J.(9 , RTITG'RR^.N inheritance .Th f eo induced imitant semi-dwarfinp penes in rice. Heredity;20(1979) J3?. (10) NARAHARI,F. Froc.Sytnp.Radiation and Radiomi- metric substance Mutation si n Breeding.Govt, of India.(1969) 17?. (11) OKUNC,F., KAWAI,T. Variatio internodf no e lengt othed an h r character inducen si d lonfc culm mutant rice.Jap.J.PI.Breedingf so . ?8 (1978) ?43. (1?) FAIMA,A., REDIT,G.M. Genetic behaviouf ro five induced dwarf mutant indien a n ei a

rice cnltivar.Crop.Sei;<17( 1977) 860. (13) RAI,K.N., DIVTVENT)I,S.L.,SnTGH,R.B. Effect of induced semi-dwarfism on panicle mor- pholop rice(Cryzn yi a sativa L.)Cereal Res. Communication ^(1978) ?85. (14) RANGANATHAN,T.E., SANGASAMY,S., MADHAVA,S.R., MENOP,P. Genetic investigation duration si n of flowering and yield in semi-dwarf varieties of rice.Int.Rice.Commn.Newsletter;?? (1973. )31 142 REDDT,T.r., PADMA,A., RTDDY,G.M. Short-culm mutants induce ricen i d .. IndPI Gend . .J an . 31 . (-16) REE,J.H. Inheritance of culm lenp-th in a cross of mutant rice variety. Mi lyanp 10. SAERAO Journal ;6( 1974) 83. (17) RUTG"n?,J.N .PETERSON, , M.L., FTT,C.H., LEHMAN,W.F. Inductio usefuf no l short statur earld ean y maturing mutant o .japonictw n si a rice cultivars. Crop Sci.;16(1976) 63% (18) RTITGER,J.N., PETERSCN,M.L. Research tool uses

of rice mutant increasinr sfo g crop productivity. Induced Mutations-A too Plann li eseichA t . IAEA,Vienna,1981 STI/PUB/591.(19«0) 457. (19) SAIflI,S.S., GAGNEJA,M.R., BRAR,G.S. Pau mutant Basmati 370-semi-dwarf, hiie-h yielding and hiprh ouaïïty rice variety .Sei.,Cult; 4^(1977) 259.

TAEIE I. l^AN IFNOTRCcm) fP INÜIVIDTJAL INT7BNCDES SEMI-DWARS CIT F D EASMATAN 0 F37 I MUTAN T DM107-4. Inter- Basmati Semi-dwarf Reduction over Easmati 370 0 37 nodemutan t (cm) No.______DM1Q7-4

*v 44.3+0.9 36.7+0.6 7.6 17

I? 23.5+0.6 19.4+0.4 4.0 17

, I P4.9+0.4 13.0+1.2 11 .«/ 48

4 I 19.3+0.3 3.6+0.2 15.7 81

I5 16.8+0.4 2.3+0.2 14.5 86

I6 12.6+0.7 0.5+0.16 12.0 96

I7 3.5+0.6 - - -

IpedunclB , e 143 TAFL MEA. EII N VALUE CCEFFICIEND SAN VARIP TO - ATIfN(C.V. YIELF )C D CCMFCtfKNTR SFO PASMATI ?70 AND ITS SEMI-DWARF MUTANTS.

Characters Basmat 0 37 iDM16-5- 1 DM107-4 ______Mean C.V. Mean C.V. Mean C.V.

Panicle 22.3b 5.7 21.1b 6.5 18.1a 9-5 axis(cm) Niimher of 10.7b 9.0 10.6b 6.0 7.8a 12.1 •priippry "branches per panicle Length of 13.0b 3.9 12.3b 4.8 12.3a 4.4 •primary "branch(cm) Number of 3.0b 8.3 2.9b 10.4 2.4a 9.8 secondary "branches/ primary "branch. Length of 3.0b 3.8 3.0b 4.2 2.9a 4.5 secondary "branchC cm) Spikelets 101.Ob 11.6 94.2b 16.3 C3.3a 14.5 "borne on secondary "branches. Total spike- 168.Ob 11.7 162.0b 10.8 104.6a 13.9 lets/panicle

Figures followed "by the same letter are not significantly differen level# 5 t ta .

i 44 TAFLE III. GRAIN YIEL HARVESD DAN T INDEP XC SEMI-DWARF MUTANT BASMATF SO I 370.

Variety/Mutant Grain yield Harvent index

DM16-5-1 341 9b 31*

? DM5- - 16 3864bc 29b

DM-? 4029 C 28*

DM.107-4 3188ab 23a

Basmati 370 2717 a ?0a

followed by the same letter are not sifmificantl?r different at 5# level.

TAPL ANALYSI. EIV VARIANCP SC PLANR E7C T HEIGHT DIALTEL4 x IN4 .

Sourcf eo Degrees of M.S. valu. P e vnriation freedom

Replications 2 9.16 0.82^ Treatments •9 1169.00 104.6** Error 18 11.2

N.S Non-s» . i pnifleant ** » Significant at 1* level.

145 TAPI ESTIÏ1ATT. EV GENETIP SC C PARAMETER PLANR SFO T HKIGHT IN RICE

Genetic parameters Estimates

D 749**0 +4. F 622**+ 112 IL, 899**+ 127

- R 748**+ 118-

h2 1908**0 ±8 E 3.7 + 19.6 ^ 1.10 0.21 K 1.35 Heritability(n.s) O.4?

N.S.» Non-sipuificant. ** = Sipnificaut at 1« level. n.s.« Narrow sense.

146 ~° BASMATI -A IRRI 3-5 -O OTHERS • - TOTAL

3-0

Fig • l-Production pattern of Rice crop in Pakistan since the introduction of Semi-dwarf varieties •

147 900-

730 -

600 -

450 -

30O-

150

— ISO

Fig-2-Vr,Wr graph for plant height in induced mutants of 4 diallex 4 ric • l n ei

148 AGRONOMIC CHARACTERISTICS OF SEMI-DWARF MUTANT LINES AND GENE ANALYSIS OF SEMI-DWARFNESS IN RICE

H. YAMAGATA, T. TANISAKA, Y. OKUMOTO, M. NISHIMURA Facult f Agricultureyo , Kyoto University, Kyoto, Japan

Abstract Agronomic characteristic f induceso d spontaneouan d s semi- dwarf mutants in rice were compared with those of the present d leadinol e th g varietied an hom n i d sforeig ean n countriesd ,an the semi-dwarf genes of a variety, Höyoku, and a line, EG 1, whic testea uses i h s r heading-tima d fo r e analysis, were examine r theifo d r allelism. 1) Five varieties which are supposed to have the semi-dwarf gene of Jukkoku showed distinct culm traits expressed as "lower- internodes elongation and somewhat slender culm". Distinct culm traits were seen als fivn i o e varieties whic presumee har o t d carry the semi-dwarf gene of Dee-geo-woo-gen (DGWG), though they were characterize "upper-internodey b d s elongatio d thicnan k culm". 2) Variations of culm traits induced from a variety were proved to be as large as comparable to those found among many cultivars. 3) Some promising induced mutants used in this study wer type "upper-internodeef th eo s elongatio d thicnan k culm". This suggests the possibility that semi-dwarf mutants which have still stronger resistanc o lodgine inducet b n mutageniy ca gb d c treatment prove1 G E posseso t d ) 4 . ssemi-dwara f gene nonallelic to that of Jukkoku, eventually to that of DGWG.

1. INTRODUCTION Soo Japann i n nationa , e afte ,th I Worle r rth dWa l demand r foofo d productio rapie th dd reconstructionan economif no c conditions accelerated the rice cultivation with an increased supply chemical fertilizers. This brought about considerable lodging as well as disease and insect injuries, and made breeders direct their effort towar establishmene th d f shortto d stiff-an - culm varieties consequencen I . numbe,a f sucro h typef so superior varieties have been release aftee on d r anotherd ,an they are now widely used in all districts of our country. This situation has inevitably caused the misunderstanding that the breeding stressed on short culm is no longer of considerable significance trute Th tha.s semi-dware h i tth f gene sources appreciate many b d y breeder e limitesar onlo t d y w stocksfe a , suc Jukkokus ha , Reimei, Fujisaka No.5, Shirosenbon, Hokuriku No.100 and some other varieties or strains which derived from these varieties or strains. Recent reports Kikuch( [1]. , al t Ikehash unpublisheie . al t ie have) d , however, suggested thasemi-dwarfine tth g locu Jukkokf so s i u identical with tha Reimeif to . This suggests also thae tth existing semi-dwarfing gene resource base is even narrower than expected.

149 Recently, some promising semi-dwarf strains, Kantö No.79, R-151, Fukei No.7 d IM-1061an mutant,e whicth e shar induced from Koshihikari, Fujiminori Norir ,o n No.8, have e comb o et widely used as new sources of semi-dwarf ness. However, genetical analysis has been still undeveloped for those induced semi-dwarf mutants, as well as for the above mentioned semi- dwarf varieties and strains. In vie f theswo e circumstances e goin ar carr o t ge t ,w ou y the genetical analysi f semi-dwarfnesso botn si h induced an d spontaneous mutations. In this paper, (1) agronomic characteristic inducef so d semi-dwarf mutant comparee sar d with the present and the old leading varieties in home and foreign countries, and (2) semi-dwarf genes of a variety Hoyoku and a whic, 1 lin testea uses G hi eE s r heading-tima d fo r e analysis in Kyoto University, are examined for their allelism.

2. MATERIALS AND METHODS . 2Agronomi1 . c characteristic mutantf so s Out of a large number of mutant stocks which were induced with r-rays, El, or NMUA from three varieties, Gimbozu, Norin NihonmasariNo.d an 8 semi-dwar2 tota,a 8 f lo f mutants, viz.,4 2 mutants derived from Gimbozu (Group G), 29 mutants from Norin No.8 (Group M) and 29 mutants from Nihonmasari (Group N), were selected for culm length so that the mean of each group might three Th be e . arounoriginacm 0 6 d l varieties were also included in respective groups. In addition to this, 6 other semi-dwarf mutants induced with r-rays or El from three varieties, viz., Hokuriku No.100 and Kanto No.79 from Koshihikari, Reimei and Fukei No.71 from Fujiminori, W-12 and W-24 from Wakaba, were used together with their three original varietie chec6 2 d k san varieties , which covered various lengths of culm. These 35 varieties and mutants were dealt wit Grous ha . pV Seedin transplantind gan g werd 28tan e h y mad Ma 16tn eo f o h of June in 1981, respectively. Fertilizers applied were 6, 9 and 9 kg/10a for N, P and K, and plant spacing was 10 x 30 cm. Heading date (HD) of each variety and mutant was recorded as the date when 50% of plants showed panicle emergence. At maturity, ten plants per variety or mutant were subjected to measurin panicle th g e number (PN), culm length (CL), panicle length (PL), firs fifto t h internode lengths (IN1-IN5), first to fourth internode thicknesses (IT1~IT4), the number of elongated internodes (EIN) and panicle weight (PW). . 2Gen.2 e analysi semi-dwarfnesf so s A serai-dwarf variety Hoyoku and a semi-dwarf line EG 1 were crosse 1979n i d . Hoyoku was, like Shiranui, derived froa m cross where Jukkok beed uha n a useparent s da . Therefore, as inferred from the result obtained by Kikuchi et al.[l],

150 Höyok s supposeui hav o t semi-dwarde eth f gene identical with that of Dee-geo-woo-gen (DGWG). EG 1 carries a gene E which controls photoperiodic sensitivity. In 1980, the F- generation (330 plants) was submitted to segregation analysis. Further progeny testing was carried out on 48 F, lines that were raised from randomly selected F- plants.

3. RESULTS 3. 1. Agronomic characteristics of semi-dwarf mutants 3. 1. 1. Culm characteristics of materials used Table I shows the line means for 12 culm characteristics representative inth e varietie d mutantsan s selected from amon; th g materials used in this experiment. In Group V, there were observed various types of culm characteristics thoug matteha coursef mutants6 ro e Th . , Reimei, Fukei No.71, Hokuriku No.100, Kantô No.79, W-1 W-24d 2an , all showed remarkable reduction of culm length as compared with their original varieties. The reduction in Reimei and Fukei No.71 is attributable to the decrease of all internode lengths, while the reduction in other 4 mutants is due mainly to the decrease of lower internodes under the second. It also attracts the attention that Reimenoticeabla s ha i e thicknesf so internodes, whic matcn hca h thos varietie4 DGWf d eo an G s closely relate DGWGo t d , Taichung Native No.l, Tongil, Millyang No.23 and Yushin. The 5 Jukkoku-type varieties comprising Jukkoku and 4 varieties closely relate Jukkokuo t d , Höyoku, Shiranui, Kokumasar d Reihöian , whic e supposehar havo t semi-dwarde eth f gene identica Jukkokuf o e l on wit,e hshoweth d similar lengths and thicknesse internodef so anothere son e samTh .e similarity was seen also DGWG-typ5 amon e th g e varieties containing DGWG closel4 e anth d y related varieties, Taichung Native No.l, Tongil, Millyang No.2 Yushind 3an , whic presumee har carro dt y the semi-dwarf gene identical with the one of DGWG. From the suggestio Kikuchy nb al.[l]t ie gene ,th e controllin semie th g - dwarfness of Jukkoku-type varieties is considered to be identical with tha DGWGf to . The remainings are some of other check varieties, showing diverse traits of culm. ther, N Als eacd n e oi groupf an werho M e, sG observe d various different type elongatiof so thickenind nan f go internodes. Thi suggesy sma littlo tn e possibilitr yfo obtaining a desired type of semi-dwarf plants by means of mutagenic treatment.

151 3. 1. 2. Variation of internode elongation o obtaiT n integratena d vief internodo w e elongation i n each group, principal components were extracted for six characters, panicle length (PL) and first to fifth internode lengths (IN1MN5 ). Component s vectors extracted from correlation matri givee ar xTabln i n. Thi I e s table shows that the first component vector group3 f so s other than d Grouan pV 'pooled' gave positive loadings to lower internode lengths, and negative one paniclo st e lengt upper-internodd an h e lengths, while those of Group Vgave positive loadings to all organs. The second component vectors of 3 groups other than Group V and 'pooled' gave positive loading organsl al o st , while thosf eo positivGroud di pV e loading uppeo st r organ negativd san e ones to lower organs. secone th e firs d Th d tan componen t vectore b n sca interpreted, as representing either a phase of variation which shows an almost proportional change in length of all organs, or phasa variatiof eo n which show relativsa e chang lengtn i e f ho organs e formeTh . r phas variatiof eo reflecy nma variatioe th t n in general size, while the latter the variation between " upper- internodes elongation" and "lower-internodes elongation". The fact that the first and the second vectors showed either of the two kinds of variation, agrees with some earlier reports [2],[3]. Figur givee1 scattee sth varietiee rth diagral al d f san mo mutants according to the scores given by the first and second component vectors extracted from principal component analysis charactersx si e clearls th i t r (PCAI .fo y ) see thin i n s figure that each of the four groups, V, G, M and N, include various type varietief so mutantr so s differen mode f th internode o n i t e elongation .mutante th Mos f o ts belongin Grouo e t g ar pN distributed close to the original variety, Nihonmasari, whereas the mutants of other groups were scattered widely. Such a narrow distributio attributable b Groun y i nma pN thao et e tth range of culm lengths of mutants used in this group was small compared with thos othen i e r groupsalss i ot I see. n4 thae th t varieties closely related to Jukkoku and the 4 varieties closely related to DGWG distributed near by Jukkoku and DGWG, respectively. This may suggest that the six characters examined strongll al e ar y affecte semi-dware th y b d f gene. 3. 1. 3. Variation of culm structure An integrated figur culf eo m structur alss ewa o obtained likewis characters8 r fo e , i.e. lengthe ,th thicknessed san f so firs fourto t h internodes (IN1-IN4, IT1~IT4). Component vectors extracted from correlations between thos charactere8 s are given in Table HI. This table shows that the first component vector interpretee b n sca representins a d phasa g f eo variation between "upper-internodes elongatio thicd nan k culm" and "lower-internodes elongation and slender culm". This suggests that the strong lodging resistance of the upper internodes elongation type rice is due not only to the shortning of lower internodes but to the thickening of all internodes.

152 Figur 2 showe e scatteth s varietiee rth diagral al d f an so m mutants characters8 obtaine e th r ds showfo A fro.A thin i nPC m s figure e sam,th e tendencie distributiof so recognizes a n r fo d internode elongation were observed also for culm structure. 3. 1. 4. Relationships between agronomic characters Mean values and correlation coefficients of and between 15 agronomic character n eaci s h grou e given I par Tabln i n. IV e e foualth lr groups, culm length (CL d upper-internod)an e length (IN1~3 or 4) were positively and highly correlated. Correlation n lengti s h betwee neighborine th n g internodes were generally high, excepting those betweee th e secon d th n an d third internode length thren i s. N ed groupan M , sG

Correlation thicknesn i s s between different internodes were extremely high. This indicates that the thickening of all internode s evenli s y controlle genetiy b d c factors throughout the whole developmental stages. . 2 Gen . e3 analysi f semi-dwarfnesso s

s showA n Fig.3i n e frequenceh , y distributio f culo n m length in the F_ following the cross between Höyoku and EG 1, ranged e continuouTh . cm widel 2 s 10 natur yo t frodistributio f eo 2 4 m n did not allow the discrete phenotypic grouping. However, the F,, segregation included plants which clearly exceeced the oarents in both directions. In minus direction, about 1/16 of the whole plants exceeded the range of the shorter parent, Hoyoku, suggesting a two-gene segregation. To confirm this, F_ progeny test of randomly chosen F. plants was conducted. The 48 F_ lines could easily be classified into 5 phenotypic groups according to the line mean and the variance within lin culn i e m length e resulTh . f classificatioo t s i n shown in Table V. According to two-gene model, the segregation ratio of [homozygous and tall] : [heterozygous and tall] : [homozygou semi-dwarfd san [heterozygou: ] semi-dwarfd san : ] resule Th t. 1 : 4 : 2 : 8 [homozygou : 1 e b dwarfd o t san s ]i obtained, 3 : 26 : 6 : 10 : 3, was quite well consistent with the expected ratio ( -£=Q.SO, 0.950

153 the semi-dwar genetis fit gen d cean background y indicatma r ,o e allelic differentiation. Nishimur] examine[3 . al dt a e multivariate variatio1 1 r nfo agronomic characters responsible for plant type using many culm- length mutants induced fro varietya m consequencn i d ,an e found out various kinds of mutations concerning plant type. Tanisaka et al.[4],[5] analyse characteristice th d larga f so e numbef ro heading-time mutants induced also from a variety, and pointed out that various type mutationf so headinn si g traits, sucs ha photoperiodic sensitivity, could frequently be induced by f-ray irradiation. It was confirmed also in this study that variations in culm traits induced from a variety were as large as comparabl thoso et e found among many cultivars.

Morishima and Oka [2] and Oka and Morishiraa {6] indicated that the upper internode elongation type gave high productivity under intensive cultivation. The fact that some promising mutants use thin i d s study, suc HS-309s ha , M-114 N-64d 6an , were proved to have the"upper-internode elongation and thick culm", may suggest the possibility that the semi-dwarf mutants which have still stronger resistance to lodging can be induced by mutagenic treatment. Since HOyoku presumably has a semi-dwarf gene identical with that of Jukkoku, the verification of two-gene hypothesis crose ith n s betwee 1 seemn G Hôyoko suggesE st d uan t 1 tha G tE possesse ssemi-dwara f gene nonalleli thao ct Jukkokuf to , eventually to that of DGWG. Though the origin of this semidwar t uncertainye f s gena s i e studie ,j warrentee b y ma s o t d determine if this gene is as useful inbreeding as the semi-dwarfing of DGWG.

REFERENCES

] KIKUCHI[1 IKEHASHI, ,F. NAKANE, ,H. YOKOO, , A. , Japan,M. . J. Breed. 31^ Suppl. 1, (1981) 138. [2] MORISHIMA, H., OKA, H., Japan. J. Genet. 43_ (1968) 181. ] NISHIMURA[3 TANISAKA, ,M. YAMAGATAH., ,T. , Japan Breed. .J . Suppl£ 3 (1980, .2 ) 204. ] TANISAKA[4 YAMAGATA, ,T. , Japan,H. Breed. .J Suppl_ .28 , .1 (1978. )36 ] TANISAKA[5 YAMAGATA, ,T. , Japan,H. Breed. .J Suppl0 .3 , .2 (1980) 206. [6] OKA, H., MORISHIMA, H., Japan. J. Genet. 43_ (1968) 191.

154 TABLE I. CHARACTERISTICS OF CULM IN REPRESENTATIVE VARIETIES AND MUTANTS

Varietie4 IT 3 mutants5 IT 2 s IT 1 IT N EI S IN 4 IN CL 3 IN PL 2 IN INI

GroupV Fuj iminori 74.6 20.6 37.8 18.9 10.4.8 50.3 4.2 1.72 3.19 3.93 4.72 Reimei 61.9 19.3 29.8 16.5 69. 4.2 0.7 4.6 1.85 3.38 4.14 5.32 Fukei No.71 39.1 17.97 2. 26. 0 49. 9 1.52. 0 00.0. 1 2.41 2.71 3.10 Koshihikari 63.9 19.3 27.7 16.7 5.11.0 40.5 4.2 1.54 2.78 3.44 4.19 Hokuriku No.100 54.1 17.1 27.4 14. 0 1.65 4. 68. 0 02.0. 3 2.79 3.37 4.09 Kantô No.79 52.6 15.0 26.7 14. 9 1.333. 6.3 92.80. 9 2.53 2.96 3.43 Wakaba 81.4 19.0 31.4 19.8 14.6 10.4 2.8 4.8 1.66 2.98 3.62 4.16 W-12 69.7 20.7 31.3 17.5 6.13.0 50.4 4.3 1.71 2.98 3.30 3.80 W-24 67.7 20.1 33.0 16.7 4.11.8 40.2 4.3 1.76 3.04 3.54 4.28 Jukkoku 54.8 17.4 20. 08 1.5 4. 13. 5 42. 0 2.5 0 9.8. 9 2 3.00 3.38 en HOyoku 65.3 17.3 26.8 14.1 7.11.8 73.0 5.1 1.61 2.79 3.24 3.67 Reihö 58.4 17.3 20.8 13.6 7.11.9 83.0 4.9 1.51 2.67 3.04 3.41 Shiranui 54.5 17.4 20. 67 1.6 4. 13. 5 11. 1 3.12 10.7. 4 63.39 3.75 Kokumasari 51.9 18.5 20.3 12.7 6.10.3 60.6 4.4 1.65 3.04 3.35 3.93 Dee-geo-woo-gen 58.8 20.5 26.0 14.4 4.10.6 61.2 5.2 2.10 3.22 4.04 5.34 Taichung Native No.l 59.6 23.0 28.3 15.3 78. 4.2 1.4 5.0 2.26 2.61 4.22 5.23 Tongil 55.1 20.6 26. 10 2.2 5. 14. 8 1 1. 3 3.4 0 6.4. 94 4.46 5.66 Millyang No.23 61.3 22.6 29. 30 2.7 5. 14.7 81. 2 3.8 7 9.4. 18 4.54 5.57 Yusin 57.6 21.7 26.2 13.1 9.4.36 1.8 5.5 2.22 3.26 4.01 4.92 Kinmaze 60.2 17.6 27.4 15.4 69. 5.8 1.6 5.0 1.51 2.45 2.75 3.24 Shirosenbon 59.4 16.0 21.9 16.3 11.7.7 80.7 4.5 1.50 2.69 3.00 3.50 Nipponbare 63.1 21.0 31.3 17.0 10.3.03 0.1 4.1 1.78 3.02 3.67 4.13 Fujisaka No.5 60.3 17.6 29.9 17. 0 1.864. 8.0 53.30. 1 3.27 4.04 4.89 Norin No.l 58.3 16.0 30.4 18.2 7.1.41 0.0 3.7 1.47 2.86 3.30 3.60 TABLE I. (CONTINUHD) Varieties § routants CL PL INI IN2 IN3 IN4 INS EIN lïl IT2 IT3 IT4

(Group V) Aichi-asahi 68.8 17.8 26.6 16.1 11.9.91 2.8 4.8 1.59 2.62 3.10 3.46 Aikoku 74.8 19.2 32.8 20. 2 1.44. 0 4 814.5.0. 5 2.79 0 3.16 3.73 Norin No.18 66.2 19.6 26.8 17.9 1 1.64. 4 11.61. 2.990 7. 3 3.22 3.79 NÔrin No.22 77.2 19.3 29.1 19. 7 1.634. 7 815.9.2. 54 2.93 3.48 3.97 Shinriki 72.7 19.1 26.2 17. 2 1.45. 4 7 813.3. 2.610.0 77 2.98 3.42 GroupG Original 68.3 17.1 26.7 16.5 12.4 8.9 2.4 4.9 1.65 2.74 3.24 3.61 IMR-19 59.1 16.0 24.5 13.4 9.9 8.9 1.8 4.9 1.73 2.70 3.05 3.41 HS-21 66.6 20.1 30.8 16.8 12.0 5.0 0.6 4.6 2.04 3.12 3.58 4.08 HS-90 42.8 17.8 17,4 10.0 7.0 5.4 1.0 4.9 1.56 2.75 3.14 3.58 HS-266 60.8 16.4 21.1 17.6 12.6 7.8 0.4 4.3 1.48 2.44 2.81 3.09 HS-309 68.0 21.0 32.8 18.5 11.2 4.4 0.4 4.4 2.04 3.38 3.88 4.48 Group M Original 76.6 19.5 31.7 19.9 14.1 7.2 1.3 4.6 1.83 3.26 3.75 4.16 0\ M-559 59.5 16.9 27.7 16.0 9.4 4.6 0.5 4.3 1.43 2.46 2.91 3.25 M- 8 05 60.3 20.9 21.6 18.4 12.5 5.9 0.2 4.2 1.83 3.20 3.84 4.30 M-824 69.0 20.4. 29.4 17.3 12.1 6.8 1.3 4.8 1.75 3.16 3.64 4.05 M-1100 58.0 18.3 22.3 17.4 10.6 5.1 0.2 4.2 1.35 2.35 2.82 3.27 M-1146 62.0 21.4 32.3 18.0 8.9 1.2 0.0 3.8 2.05 3.76 4.27 4.54 Group N Original 60.7 19.1 28.8 15.7 10.0 4.5 0.4 4.3 1.62 2.71 3.18 3.59 N-24 60.9 17.1 27.9 15.0 10.5 5.5 0.5 4.3 1.69 2.83 3.23 3.79 N-40 55.9 17.6 25.7 13.4 9.5 5.3 1.1 4.5 1.31 1.99 2.28 2.77 N-64 58.8 20.1 29.8 14.6 8.7 4.1 0.3 4.3 1.87 3.00 3.36 3.90 N-100 64.8 18.6 29.5 15.2 11.6 6.3 0.6 4.5 1.68 2.69 3.13 3.57 N-179 56.2 19.9 27.6 14.2 9.2 3.5 0.4 4.3 1.63 2.69 3.17 3.69

Figure shows the line mean. CLiCulm length(cm), PL:Panicle length(cra), INl~IN5:First to fifth internode lengths(cm), EIN:Number of elongated internodes, IT1~IT4:First to fourth internode diameters (cm). TABL COMPONEN. H E T VECTORS EXTRACTED FROM CORRELATIONS BETWEEN PANICLE LENGT INTERNODD HAN E LENGTHS

Group V Group G Group M Group N Pooled Organ T Zl Z2 V Z2 Zl Z2 Zl Z2 Zl "2 PL .039 .502 -.515 .490 -.498 .288 -.409 .593 -.368 .479 INI .150 .927 -.840 .278 -.782 .338 -.582 .680 -.554 .685 IN2 .640 .662 -.494 .722 -.571 .696 -.261 .833 .054 .875 IN3 .928 .095 .317 .879 .425 .838 .639 .651 .696 .616 IN4 .909 -.365 .813 .489 .888 .389 .888 .372 .947 .154 IN5 .647 -.528 .789 .208 .796 .128 .831 .126 .784 -.088

Contribution .423 .329 .433 .316 .465 .259 .410 .348 .407 .313 PL : Panicle length, IN1~IN5 : First to fifth internode lengths.

c/» TABL . COMPONENHI E T VECTORS EXTRACTED FROM CORRELATIONS BETWEE E LENGTHNTH DIAMETERD SAN UPPEF SO 4 INTERNODER S

Group V Group G Group M Group N Pooled Organ Zl Z2 Zl Z2 Zl Z2 Zl Z2 Zl Z2 INI .340 .586 .850 .310 .524 -.548 .671 .353 .457 .123 IN2 -.033 .907 .342 .787 .501 -.137 .500 .667 .259 .738 IN3 -.353 .847 -.339 .888 .062 .812 -.304 .898 -.185 .938 IN4 -.424 .583 -.706 .447 -.409 .848 -.465 .718 -.389 .706 IT1 .927 -.012 .787 .128 .870 .273 .908 -.010 .886 -.032 IT2 .950 .142 .924 .017 .940 .125 .947 .093 .941 .097 IT3 .971 .151 .900 -.065 .942 .139 .941 .085 .954 .084 IT4 .966 .107 .891 .027 .928 .178 .882 -.141 .935 .059

Contribution .508 .285 .566 .216 .511 .230 .549 .241 .490 .245 IN1~IN4 : First to fourth internode lengths, IT1—IT Firs: 4 fourto t h internode diameters. TABLE IV. MEAN VALUES AND CORRELATION COEFFICIENTS OF 15 AGRONOMIC CHARACTERS IN 4 GROUPS Group V

Group G Mean D 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) Mean

1)HD 107.9 .13 .12 .17 -.51 -.24 .38 .76 .58 .76 -.11 -.14 -.47 -.59 -.69 108.2

2)PN 7.8 -.03 .10 .27 .11 -.01 -.04 .05 -.01 .13 .24 .30 .28 .27 .05 7.7

3)CL 62.5 .23 -.43 .45 .52 .78 .74 .36 .07 .26 .51 .30 .20 .12 .16 60.6

4)PL 18.8 .01 -.52 .22 .52 .37 .16 -.15 -.17 .11 .65 .68 .49 .41 .35 17.9

5) INI 27.6 -.44 -.34 .61 .42 .55 -.06 -.51 -.47 -.47 .56 .68 .72 .70 .67 26.3

6)IN2 16.0 -.08 -.32 .87 .10 .68 .47 -.09 -.27 -.20 .51 .18 .25 .21 .31 15.8 en 00 7)IN3 10.5 .50 -.32 .83 .02 .16 .66 .66 .30 .52 .09 -.12 -.28 -.32 -.23 10.4

8)IN4 5.6 .76 -.22 .62 -.10 -.21 .31 .80 .68 .86 -.11 -.32 -.53 -.59 -.60 5.7

S IN ) 9 1.3 .66 -.11 .34 .01 -.29 -.02 .40 .76 .60 -.19 -.41 -.52 -.47 -.47 1.2

10)EIN 4.6 .65 -.17 .28 .27 -.27 .00 .38 .62 .78 .07 -.09 -.35 -.51 -.48 4.4

11)PW 2.2 -.01 -.50 .26 .87 .38 .16 .08 -.04 .04 .38 .55 .49 .41 .50 1.8

12)IT1 1.7 -.03 -.33 -.07 .82 .18 -.15 -.26 -.22 .03 .34 .88 .82 .64 .60 1.7

13)IT2 3.0 -.11 -.33 .04 .78 .27 .04 -.16 -.21 -.08 .24 .87 .91 .80 .82 2.9

14)IT3 3.5 -.24 -.37 .05 .76 .33 .08 -.19 -.26 -.11 .19 .86 .89 .96 .83 3.3

15)IT4 4.1 -.26 -.37 .01 .75 .30 .04 -.21 -.29 -.14 .21 .85 .89 .93 .98 3.9 TABLE IV.(CONTINUED) Group M

Group N Mean D 2) 3) 4) 5) 6) 7) 8) 9) 10) H) 12) 13) 14) 15) Mean

1)HD 111.1 -.12 .10 .33 -.01 .17 .22 -.06 -.01 .05 .18 .04 .14 .12 -.07 100.1

2)PN 8.2 -.43 .13 .21 .04 .05 .17 .18 .10 .01 -.09 -.08 -.09 -.08 -.21 8.3 3)CL 60.7 -.10 .06 .35 .60 .70 .74 .60 .30 .30 .24 .12 .24 .20 -.00 59.7

4)PL 18.2 -.26 .09 .22 .51 .38 .09 -.15 -.15 -.06 .54 .33 .41 .41 .34 19.3

I IN ) 5 25.1 -.51 .34 .68 .37 .67 .01 -.22 -.33 -.13 .46 .49 .58 .51 .42 28.4

6)IN2 16.4 -.41 .32 .78 .24 .65 .36 .03 -.12 -.07 .13 .39 .44 .42 .24 14.9

7) INS 11.1 .32 -.28 .57 .03 -.13 .29 .80 .43 .26 -.01 -.27 -.17 -.15 -.34 9.9 u» 8)IN4 5.5 .68 -.43 .15 -.32 -.54 -.23 .67 .73 .55 -.11 -.35 -.30 -.28 -.40 4.6

9) INS 0.8 .61 -.35 .04 -.24 -.38 -.39 .30 .73 .86 -.27 -.50 -.43 -.42 -.52 0.6

10)EIN 4.5 .68 -.38 -.07 -.35 -.49 -.50 .29 .75 .93 .01 -.25 -.16 -.17 -.25 4.4

11)PW 2.2 -.01 -.11 .52 .46 .24 .39 .50 .17 .10 .03 .66 .73 .71 .67 2.3

12)IT1 1.7 -.23 -.15 .17 .37 .18 .21 .12 -.14 -.03 -.09 .69 .87 .87 .76 1.7

13)IT2 3.0 -.31 -.05 .22 .48 .33 .27 .03 -.28 -.09 -.20 .66 .94 .95 .83 2.8

14)IT3 3.5 -.40 .03 .21 .65 .32 .29 .08 -.29 -.12 -.28 .60 .85 .92 .88 3.2

4 IT ) 15 3.9 -.50 .10 .30 .55 .34 .41 .20 -.26 -.18 -.31 .61 .80 .85 .93 3.6

HD:Days to heading, PN:Panicle number, CL:Culm length(cm), PLtPanicle lengtli(cm), INI ~IN5: First to fifth internode lengths(cm), EIN:Nuraber of elongated internodes, ITl~IT4:First to fourth internode diameters. TABLE V. CLASSIFICATION OF 48 FS LINES ACCORDING TO THE CULM LENGTH E CROSITH N S BETWEEN1 HÖYOKG E D UAN

F_ class Observed Expected Number Ratio

Horaozygous, tall 3 3 1 Heterozygous, tall 26 24 8

Homozygous, semi-dwarf 6 6 2

Heterozygous, semi-dwarf 10 12 4

Homozygous, dwarf 3 3 1

( *N0.50 , 0.950< P< 0.975 ) Test of two-gene hypothesis with expectation of 9 : 6 : 1 segregatio. F_ n i n

160 Varietie: O f Grouo s V p rMutantD f o Grous G p A: Mutants of Group M Mutant: 0 f Grouo s N p • : Variety Gimbozu : VarietA y Norin No.8 : Variet^ y Nihonmasari Variet: X y Jukkoku j Variet: -h y Dee-geo-woo-ge2 n © :Varieties closely related to Jukkoku ' 3.0 •rVarieties closely related o Dee-geo-woo-get n O O A 0 - 2.0 O HS-309 f V ) . Q A M-1146 Ä _ Ç O n VAA D Q • D O -A — rA_,_a — D — 0 — ..... —— i- z. 0 -3 -2* 0^Ö^V^^JO ^ ^AuOl.O 2^0 3.0 l N-64 00 A/£ 0 A-Q © Q A E% & v A 0 A a CbO . .O. .OA 9^x © a ©A IB» s p 0 < o o a • -2.0

1 Fuke7 . No i • a -3.0 O

• -4.0

Pig. 1. Scatter diagram of 120 varieties and mutants according to the scores given by the first and second component vectors extracte characters6 r dfo froA PC m .

161 O:Varieties of Group V D :Mutants of Group G A :Mutants of Group M 0:Mutants of Group N Variet: • y Gimbozu Z2 A:Variety Norin No.8 ^tVariety Nihonmasari X:Variety Jukkoku •• 3.0 •f=:Variety Dee-geo-woo-gen O @: Varieties closely related to Jukkoku :Varietie• s closely related 0 2. ' • O to Dee-geo-woo-gen

HS-309

"4#7 3.0 4.0 o o

Fukei No.71 " -4.0 O

Fig. 2. Scatter diagram of 120 varieties and mutants according to the scores firs e give seconth d ty an n b d component vectors extracte characters8 r dfo froA mPC .

162 EG 1 30 —o- Höyoku n_ !/) •P

U20 f-i (1)

I T r I I I 40 50 60 70 80 90 100 Culm ) m lengtc ( h

Pig. 3. Frequency distribution for culm length in F 2 following the cross between Höyoku and EG 1.

163 GENETIC EVALUATION OF PLANT TYPE VARIANTS FOR DESIRABLE PHYSIOLOGICAL ATTRIBUTE E STUDE TH TH F THEIYN O D I E SAN RUS PHYSIOLOGICAL BASI YIELF SO RICEN DI *

E.A. SIDDIQ, P.R. REDDY Division of Genetics, Indian Agricultural Research Institute, New Delhi, India

Abstract

e presenTh t investigatio s undertakewa n o contributt n e basic information on the physiological basis of yield and the growing interest among rice breeders to recombine ideal physiological attributes into otherwise well-adapted agronomic base r differenfo s t agroclimatic conditions e extenTh .f exploitablo t e variatio r varioufo n s physiological characteristics, the nature of inter-relationships among them and their relative contribution to biological and economic yields were studie 0 plan5 n i td type variant f spontaneouso s , induced and hybrid origin. The study revealed wide variation for 24 physiological attributes under study. Heritable components of variation were high for most characteristics. Genotypes promisin s potentiaa g l donors in cross breeding programme were identified e patterTh . n varied with genotypes Manipuri Mutant 6 R exhibite480-5-9-3 I , R I e d th 3an d highest rate, respectively, at the seedling-tillering, tillering- flowering d flowering-maturitan , y phases. Genotype, s 18 lik G M e 2 wer4 R eI characterized an I8 R n evea y nb d growth rate througe th h growth cycle e trenTh f .N-uptako d e ability also differe r entriefo d s lik R 480-5-9-3 I ed improve an 6 3 dR , I Sabarmati, which manifest high uptake abilite lateth t ra y stavew likfe ef growta o s d an h improved Sabarmati exhibited high Nitrate reductase (NR) activity. Simple correlation coefficients computed for different character pairs revealed a close positive association between grain and biological yields. The turin y n were positivelfounbe to d y related to major physiological attribures like CGR, N-uptake and harvest index. Path analysis for biological yield indicated that N-uptake R abilit(wholCG d ean y duration) contribute both directl- in d an y directly through other characteristics like LAI. Contributing directly and indirectly through N-uptake ability, t floweringCGR(a I ,LA d sin)an k size, harvest index was found to be the major determinant of grain yield. On the basis of the present findings there appear to be both prospects and limitation e approacth n i sf physiologica o h l manipulation for raising the yield ceiling of rice.

Research supported under IAEA Research Contract No. 2986/RB.

165 Introduction

e basi th f avialabl o sn O e solad r energm l f abouca o y 0 3 t during the monsoon season, the highest theoretical yield of rice has been estimated to be 12 tons/ha for a medium duration variet s againsa y 6 t/ha5- t , dependin e leve th managementf o ln o g , at research stations compared with the national average of 2.30 t/h (1981-82) in India. In other words, only between 25 and 40 percent of its potential has been exploited, which represents a vast gap of untapped yield reservoir. While efforts are being made to bridge this gap, a similar analysis, based on the analysi f constrainto s o explort s e possibilitieth e f raisino s g further the genetic potential itself, reveals the existance of an equally wide gap between the biological ceiling and the highest levels achievable through the presently available varietal base. An hypothetical breakdown of the research gap suggests its major component e physiologicab o t s n naturei l . But, very littls i e yet known abou e exploitablth t e genetic variability available including the nature of interrelationships of this variation and its relative contribution o biologicat s d economian l c yields. e genetiTh c behaviou d amenabilitan r f thio y s variatioo t n breeding manipulations. The present study was undertaken using a set of plant type variants of induced, spontaneous and hybrid origin witfollowine th h g objective: s

(1) To estimate the extent of variation for various physiological attributes.

(2) To study the nature of associaitons between different character pairs.

(3) To determine the relative contribution of various physiological components to biological adn economic yields.

The major findings form this study are presented in this paper.

Materia d Methodan l s

(1) Estimating the extent of variation:

Experimental materia 0 genotype5 f o l s included plant type mutation f induceo s d spontaneouan d s w elitorigife a es wel a ns a l breeding lines and popular varieties. The source and salient features of the material are summarized in table 1. e materiaTh s growRandomizea wa ln i n d Complete Block Design wito replicationstw h . Twenty-fiv d seedlingol y da e s were transplanted under recommended levels of fertilizers (100N : 40 :40K), adopting a uniform spacing of 15 x 15 cm. Observations at appropriate stages of growth were recorded on 24 different characteristics which included economic yield, growth, biochemical and morphological parameters. Standard methods were use n recordin i de variable th l al g s either on the basis of the unit area or single plant, depending on the character under study.

166 Economie yield parameter s,,Biologica; lgrai, d straan n w yields were estimated in terms of gm/m at comparable moisture levels while harvest indes (HI s compute)wa s followsa d : Grain yield ______0 10 x Tota y MatteDr l r yield Sink sizs estimatewa e n termi d f boto s h volume s measure,a d by liquid displacement using rectified spirit, and weight of grains a singl n o em i g nplan t basis. 2 Growth parameters; Biomass accumulation ocnverted to gm/m was determined using 5-hill plant samples at seedling, tillering and flowering stage oven-dryiny b s 4 hours)2 r gfo .methoC 0 (7 d Crop growth rate (CGR) for a unit area of canopy cover at any given time (t) may be defined as the increase in plant material per unit of time. CGR was computed for four different growth intervals viz., seedling to tillering, tillering to flowering, flowering to maturit d seedlinan y maturito t g y usin e followinth g g formulf o a Radford (1967) 1

21 e plan - respectivelyweighty ar t dr „ td W an t timd a s 1 an whert e . W e. Net assimilation rate s (NARcomputee samwa th )e r growtfo d h interval s thaCGRr a s fo t, usin formule th g f RAdforo a d (1967) (1 ) as under:

NAR = W2 - Wl

e plan ar y weight dr „ tW d lead an swheran f . areaW. e t timea s s . t- d tan , Leaf area index was computed as under: ______Lea f area (sq.dm) f lano m dd are. Sq a covere = y plantb d I sLA

whereas leaf area ratio s determine(LARwa ) d usin e formulth g a W g lo - . W g Lo A - , A LAR = ——————- . ——-———-—————-——- x W - 2 W - _ log Aj 2 logeA e

Biochemical parameters; Estimation f N-contenso d N-uptakan t e at the three different growth stages and at maturity was done for total nitrogen content following Microkjeldahl method (A.O.A.C., 1965) (2). Nitrogen uptake was calculated using plant dry matter yields at the various stages of growth as per cent N in the plant as follows: 2 2 matteceny r N uptakdr pe N t gm/n x i r = me (gm/m 100 Nitrate reductase (NR) activity was assayed at the seedling, tillering, flowering and maturity phases of plant growth. The method followe s similad wa dan ) thao t r(3 Kleppef o tl a t e r Hagema Huchlesbd an n ) wit(4 y h slight modification. Nitrate s determinewa methoe th Evaf y Nasod o b d an n n (6) e activit.Th y of enzym s expresseewa millimicromoles a d 2 m formeg N0 r f o spe d fresh weight per hr.

167 Statistical analysis: Differences between genotypes for different characteristics were tested for significance fay using an analysi f varianco s e technique (7).

The genotypic and phenotypic coefficient of variation were calculate e formulath y b d e give y Burtob n n (8), whereas broad sense heritability was worked out using the formula of Hanson et al.(9).

) Natur(2 f associationo e s between various character pairs:

observations made on the same set of 50 entries used in the previous experiment forme e datath d . Simple correlation coefficients were computed o tese T significanc.th t f correlatioo e n coefficients e phenotypiath t c level e estimateth , d values were compared with table values (10 t (t-2)a ) 0 leveldegree17 f probabilityd o sf freedo an o s 5 t a m ,

(3) Relative contribution of various characters to biological and economic yields:

The same 50 genotypes used in the Experiment 1 constituted the f charactero materialt se e sTh . include r thifo ds study, howevers ,wa restricted to 12. Estimates of direct and indirect contributions of various characteristics were calculated through path coefficient analysi s suggestea s Wrighy b d t (11 d elaborate)an u (12) L y Dewe b dd .an y

Results and Discussion

Ever isnce the introduction of non—lodging dwarf rice varieties to the tropical world, there have been attempts to study the morpho- physiological basis of their high yield potential. Inferences drawn therefrom thae physiologicath t l basi f yielo s s quiti d e compled an x that various component indice f physiologicao s l potence ar y interrelated in their mode of functioning in a given agroclimate, are base n studieo d w representativf onlfe o s a y e plant types. Inadequate information on the extent of exploitable variation for, the nature of relationshi pe relativ th between n o ed contributio,an o biologicalt n / economic yield f variouo s s characteristic s attributabli s e largely e factth ot thal previoual t s studies were made fro a physiologist'm s point of view rather than that of a breeder or geneticist. This information gap has prompted the present study on the various aspects as discussed below:

Variation for physiological attributes

Highly significant differences amon e genotypeth g s were found for the extent of variation for 24 different physiological attributes using agronomic, growth and biochemical parameters in 50 plant type variants. Estimate f rangeo s , mead genotypian n c phenotypic coefficients of variation (Table II) suggest a wide variability for a majority of the variables, as discussed below.

Agronomic parameters: Genetic potentia a cro f po l plat s determinei n d largels it y b y economic yield whic cerealn i h s synonymoui s s with grain yieldr Fo . obtaining high grain yields, balanced growth at different stages of

168 developmen s necessari t d particularlan y e reproductivth t a y e phase when apportionment of total dry matter for grain filling takes place. This implies indirectly thae genetith t c abilita f o y plan o product t a hige h biologica le foremosyielth s i d t amone th g physiological prerequisites for ensuring high grain yields. The abilit o product y y mattedr e r ove o apportiort timd an e betweet i n n vegetative parts and grain varies with genotypes. A wide variability for biological grain and straw yields was observed, the ranges being 512 - 1705 gm, 158 - 756 gm and 353 gm, respectively. Among the 50 different genotypes evaluated IR 30 had the highest biological and straw yields, whereas IR 4432-28-5 was the highest grain yielder (Table II and III). Among the genotypes tested IR 4432-28-5, IR 30, IR 480-5-9-3, , Iimprove8 R d Sabarmat d IARan i I e promisin590ar 2 1- g grain yielders with proportionately high biological yields. An interesting coincidence here is that all the types listed above are short statured, and all except IARI 5901-2 carry the DGWG dwarfing gene. Since there are exceptions it would be unwise to generalize that all genotypes that carry the DGWG dwarfing gene would guarantee high biological and grain yields. At the same time, it should not escape attention that spontaneous dwarfs such as IARI 5901-2 and induced dwarfs like Mahsuri Mutant-1, MM.Df S.,, MM.Df S.„ etc. are also capabl f showino e g comparable performance. Thaphysiologicae th t l performance of an induced or spontaneous mutant can be improved by cross breeding and selection is evident by comparing the performanc f DGWo d ehig an Gh yielding, IRRI varietie s wela ss a l the Harabal icross Mutanit sd brean t d derivative Pusa 317. As high harvest index (HI) is considered to represent an increased physiological capacity to mobilize and translocate photosyn-thates into organs of economic value, it has been suggested as a reliable selecion index for improving grain yields in cereal crops. In the present investigation wide variation for HI was evident from the width of range (31.0 to 46.77») as well as high genotypic and phenotypic coefficient of variation (Table II). High estimates of heritability suggest that it is a relatively stable character, least influenced by environment. The data further reveal that HI need not always be proportionate to the absolute biological or grain yield. Among the entries studied, a few like improve 4432-28-5R I , d8 R SabarmatiI ,, DGWG89 C ,,ND IARI 7312B, IARI 5901-2 Mahsuri Mutant-1, and CAM have a high HI (Table I). It is further evident that HI, although predominently high in semidwarfs s independeni , f plano t t height, suggesting tha nona t - lodging semi tall with high HI would also yield as good as a semi-dwarf type, (see also 20). Several investigator e pasth t n i havs e suggeste e possibilitth d y of increasing grain yield of cereal crops by combining optimal dura- tiovegetativr fo n e growt d graian h n filling. Daynar d Kannenbordan a (22) for instance, report positive relationships between the length of the grain filling period and grain yield in corn. In rice the vegetative parts stop growing after flowerin e earth o .t g Accordingly, increasen i s tota y mattedr ld carbohydratean r s durin e postflowerinth g g period sho a wclos e association with grain yield A widd .significan an e t variation (21-35 days s observegraie )wa th nr fo dfillin g period presene ith n t stud d varieties/mutantan y , Mahsur30 sR I suc is a h Mutant-1, MM D S.,, Mutant Basmati etc. having a long grain filling phase e promisingb see o t m hourw n arealo I f sunshin .o sf o s e

169 durin pose th gt flowerin ge crop phasth ,f prolongea o e d grain filling period might permit a high net assimilation rate and a high translocation of assimilates. An invariably long grain filling period may lea o increaset d d graio sizeablt y n ke tes a e te b weight y ma t i , yield improvement d thers exploitationan s it s scop i er fo e . Physiologists believe that the physiological basis of yield cae understoob n d onl y understandinb y e source-sinth g k relationship. In view of the relative importance of the sink as related by various workers (25-28) for realizing higher economic yields, suggesting that other factors, like translocation efficienc r inabilito y e sourcth f eo y to meet the sink demand might have affected the filling process.

Growth Parameters

Biomass accumulatio d croan np growth rate: Translocation efficiency would depen photo-synthate th mucs a dn ho r biomaso e s produced e demanth n a do se sink e leveabilitth Th .f plana o l f produco o yt t e biomass is determined in terms of absolute values at different growth e rat stagef th biomaso e d an s s increase betwee o consecutivtw n e growth stages. Wide differences occur among the genotypes for biomass production at different stages of growth. The differences among the genotypes was relatively narrow at the initial stages but tended to widen with further growth. Although the increase is cumulative with time, the growth pattern varies witgenotype th h e (Fig.l) r instancFo . e Manipuri Mutana riap s dha t biomass accumulation betweee th n seedlin d tillerinan g g stages a slo t w,bu rat f increaso e e e subsequenith n t stagese otheth rn O .hand e ratf th ,o e biomass accumulation in IR 30 is low up to flowering, but rapid from flowerin maturityo t g . Unlik e extremth e e patterne th f o s above, the culture IR 480-5-9-3 shows a steady and gradual increase in biomass accumulation. Variation r crofo sp growth rats beeha e n studie y othersb d . In conformity it was observed that the CGR differs widely among genotypes (Table II). The pattern of growth rate curves is by and large normal, the rate showing and increasing trend from the seedling to tillering phases, attaining maximu t tillering-floweringa m , with decreasing trend from flowering to maturity. The genotypic differences are obvious in the rates at different phases as well as in slight deviations from the normal pattern(Fig. 2). Differential rate f f growtparticulao o s e har r e valueth n I . first place, varieties with differnet crop growth rate patterns are required to suit different agroclimatic situations. For instance, for upland and directly seeded varieties, a rapid growth rate during pretillering phase could enable plants to compete successfully with fast-growing weeds. Similarly, rapid growth rate would be advantageou varietien i s whicr vegetative fo s th h e phase (particularly the maximum tillering phase) falls withi e perioth n f heavo d y monsoo d cloudnan y weather. Secondly harvese ,th t index would itself depen n growto d h rat t particulaa e r stages r instanceFo . s i t i , known that a high CGR prior to flowering would ensure a high sink index size via grain number, while a high CGR during post flowering phase would affec e sinth tk weigh d levean t f spikeleo l t fertility. A few genotypes appear promising from this point of view. Genotypes like MG 68, IR 480-5-9-3 and IR 36 have a higher CGR at all three phases, wherea2 4 R I sd an som 6 e3 R gneotypesI , 8 R I , 18 l.ik G M e exhibit a steady and gradual increase all through their growth duration. In genotypes like Improved Sabarmati, the high

170 growth rat s restrictei e e tillering-flowerinth o t d g phase onlye Th . most interesting observatio s thae i genotypen th t s diffen i r their tendency for growth from flowering, with the majority showin a declining g trend, some maintaining mor r lese o esam th se n priotreni s a rw exhibitind fe stages a d n an ,upwara g d trendt bu , aa relativelt y slow rate A groupin .e genotype th f o g n thio s s basis of their tren: is d

Flowering Maturity Varieties

Upward trend MG 63, MG 69, IR 36, IR 42

Static trend 5 8 G M , 18 G MahsuriM , 19 G ,M R 5853-118-I , P 30 317-2-7-1 R I 5 , 8 R I ,

Downward trend Rest of the cultures

Crop growth rate for the whole duration varies from 5.07 in MG 44 to 14.20 in IR 30. These differences to be decided largely by biomass accumulation during the tillering-flowering and/or flowering- maturity phases. Interestingly, all high yielding dwarf varieties have a high crop growth rate at the second phase and a comparable rate e thirath t d phase. Exploitatio f theso n e identifier o e d on source r fo f higo R s CG h the other phases of growth would go a long way in breeding varieties adaptabl o specifit e c agroclimatic situation. Leaf area index and net assimilation rate: Crop growth or biomass accumulation is the product of LAI and net assimilation rate. LAI being an indirect measure of photosynthetic area, ensuring of tis optimum level is essential for achieving high biomass produciton. Though all vegetative parts of the plant stop growing after anthesis (23-24) the maintenance of a sufficient LAI is vital for the plant to perform optimum photosynthesis. During this period the maximum of photosynthates are directed to the development of grain. However, the optimum LAI for high efficiency varies with plant height lodging tendenc d leaan y f orientation. A wide variabilits observedwa I LA n .i y (Table II) n general.I , LAI tends to increase up to flowering and slows down thereagter. Among the genotypes studied, Pusa 317-2-11-1, Manipuri Mutant, Jarabali Mutant, CAM, CH 45, NDC 89, IR 4432-28-5, IR 8 and Improved Sabarmati maintained relatively higI valueLA h s throug postanthesie th h s phase when nearly all photosynthates flow towar e graith d n sink. Among suce genotypesth h , Mahsuri Mutant-1, MG 85, MG 69, IARI 5901-2, IR 30, IR 36, IR 42 and IR 53-28-5 may be important. While leaf area constitutes the major photosynthetic area , leaf d culan m angles determin e canopth e y structur varietya f o ee resultTh . s e presenoth f t stud f leao y f angles also reveal wide variation (Table II), Amon entriee th g s studied genotype4 1 s man, a s a y s which include mostly induced dwarf r theio s r derivatives, have narrowleaf angles. Jarabali Mutant, CAM, MM D S. etc. exhibit a very close flat leaf angle, thereby

171 making the plant look upright. With respect to culm angle, the data again reveal a wide variation, the range being between 9.40 and 68.0. Heritability estimate e traitth n o s were e highfounb o t .d Froa m breeding poin f viewo t , genotypes like Mahsrui ™ Mutatn-1S. F D M ,M CAM, IARI 5901-2 have promise.

Biochemical parameters;

Nitrate reductas e enzymth s i ee that catalyzes reductiof o n nitrat o nitritet e a ,rate-limitin e reductiog th ste n i p f nitrato n e to ammonia (33) Since inflo f reduceo w e controlle b N dinpu y ma t o t d a great extenR activityN y b t , Hagema l (34)hypothesisa t e n e that under conditions of non-limiting soil nitrate, plants with high levels of NR activity should posses a greates r potentia r accumulatinfo l g reduce. N d NR activity should the e positivlb n y associated with general productivity as well as grain and grain protein yields. Under active nitrate reduction, various metabolic processes connected with the formation of amino acids and proteins may be accelerated. According to Khan and Tsunoda (35) leaf nitrogen which is largely in the form of reduced N, correlates stronly wite rat f th photosynthesisho e . The results of the present study on the extent of variation for NR activity are broadly in agreement with earlier reports (36-37). All genotypes included shoe samth we pattere enzymth f eo n activity (Fig.4). NR activity decreases from the seedling stage with the progressio f growtho n . Nevertheless, genotypes diffe n theii r r level of activit t differena y t stages. Genotypes like Jarabali Mutant, Improved Sabarmati y virtub 5 R 480-5-9-f thei4 I ,o e G M r d showin3an g consistently high activity at all stages seem to be promising. High estimate f heritabilito s y characteristi o thit c s trait brighte e scopth n e of breedin R activitN r fo go desire t y d levels, provide e observeth d d genotypic differences under transplanted conditions is the same or more under direct-seeded upland conditions.

Response of plants to applied nitrogen as measured by yield and yield components is largely decided by th plant type; weak-stemmed tall types are less responsive that stiff-culmed dwarf types. But, within such groups genotype e know ar s varo r theit n fo y r N-uptake ability, measured by leaf N content at different stages of growth (38). N-uptake estimates in the present study at the seedling tillering and flowering stages adn at maturity although registering an increase throughout the crop growth period, show that genotypes differ in their rate of N uptake at different stages. (Fig.5).(Table II). For instance, the uptake is rapid from the seedling to tillering stage, indicating this growth interval to be the most active phase for N accumulation. The observed reduction in the N uptake rates at later stages probably are due to the progressive dilution by the increased accumulation of biomass, Similar trends have been reported earlie n ricei r . (39-40). In respect of the quantum and pattern of N-uptake, genotypes differ widely. In IR 480-5-9-3, IR 36 and IMproved Sabarmati, N uptake is relatively low at the initial growth stage but tend to increase remarkably in the later phases, whereas it is the reverse in types like MG 68. Lines promising high uptake ability at different stage e listear s n Tabli d e III. Heritabilit e characteth f o y r appears to be high as is the case for NR activity. The present study has helped identify a number of promising donor sources (Table III r high/optimufo ) m physiological efficiency, apart

172 from providing basic information on the extent of heritable variation for and fixability of the characteristics. Among the promising genotypes those which combine higher efficienc a maximu r fo y m numbe f physiologicao r l attributes (Table TV) would be of particular value to rice breeders engagee tas th f raisino kn i de yielth g d level towar e biologicath d l ceiling by recombination breeding.

Natur f associatioo e n between different character pairs

Spectacular yield increases achieved in wheat and rice recently are considere o result d t from increase I (13-14)H d .s bee ha Thu nI H s suggested as an effective and reliable selection index to improve grain yield n suci s h crops. (13-17). However, considering thaI H t could be manipulated only to a certain maximum without depleting effects n vegetativo e components ther s neer placini e fo d g equal emphasis e simultaneouth n o s improvemen f biologicao t l yield. Although simple correlation analyse e presenth n i st study sho a wstron d positivan g e correlation between grain yield, totaldry matter and harvest index, very e variouth w littlsho physiologicao s knowt i e s a n l attributee ar s relate o thest d e parameters. In general, grain yields show a relatively stronger positive association wit, graiHI h n filling period, sink volume, sink weight, biomass accumulation R (tillerinCG , g stage onwards) I (tillerin,LA d an g flowering) N-content, N-uptake (tillerin d floweringan g ) etc. than biological yields. The trend of the relationship in respect of HI is sam s thar a graie fo t n yield (Table VI). With respect to improving biological yield, parameters like CGR, LAI and N-uptake appear important as is evident from their relatively higher correlation coefficients. In turn, CGR, LAI and N-uptak e positivelar e y associated with each other e observeTh . d relationship among the s understandabli m a hig s a he growth ratd N-uptakan e e a luxurianlea o t d t leaf growt d higan h h LAI. High LAI, especiallt a y the flowering stage is very important not only for realizing high biomass production t alsr higbu ,fo o h grain productione higth hs i t I . photosynthate productio e hig tha, I n prioth s possiblLA hi to t r e du e to flowering, that would help determine the size of the sink per unit land area. In view of such an association, selective improvement of evee characteon n r would hel o improvt p e simultaneousl e otheth y r components throug e correlateth h d response, resultin n increasea n i g d biological yield. Upright plant statur s closeli e y relate o biologicat d l yiels a d is evident form the negative correlation of biological yield with lead and culm angles. "This is wholly because of least shading effect s optimumoccuri I LA s .e whe th Thusn e abilitth ,a plan f o o yt t trae maximuth p m energy depend n functionao s l photosynthetic area which is ensured by LAI as affected by leaf and culm disposition. e importancTh f nitrato e e reductase activit a selectio s a y n criterion for high grain yield and high grain protein in plant breeding programme s beeha sn stresse y severab d l workers. (34, 41-43). e presenIth n t stud a correlatioy n only betwee R activitN n d graian y n protein was observed. NR activity did not show a significant relationship with grai d biologicaan n l yields s reportea , d als y Fakoredb o d an e Mock (44) in maize. Nitrogen uptake ability, which is positively associated with NR activity, LAI, crop duratbn and sink size affects the interrelated physiological changes that lead to higher biomass/grain production.

173 The grain filling period also has been found to have a positive relationship to grain yield and HI, like crop growth rate. This observation follows tha f Vergar. o tLonge al t e ar periodf o s grain filling would impl t onl no ya higy h source potentia t alsbu la o high sink size. This is borne out by the positive relationship observee graith nr fo fillind g period with sink volumd an e sink weight. Thue presenth s t findings reveal major role f growto s h rate, r increasinfo N-uptak I H d gan e biologica d graian l n yields e relativth , e importanc f otheo e r physiological parameters, particularly LAI, NAR, grain filling period, sink capacit d leaan y f angle have been identified.

Relative contributions of various physiological components to biologica d economian l c yields.

When causal factors are interrelated, it is necessary to know whether component characters directly or indirectly contribute to complex characters like grain or biological yields. Path coefficient values relatin e relativth o t g e contributions of different physiological characters through direct and indirect effects reveal that total N-uptake at maturity followed by CGR (whole duration) contribute substantiall o biologicat y l yielde Th . importanc f theso eo parametertw e n determinini s e biomasth g s production is evident also from their indirect contributions through other characters (Table VI). Through parameters like LAI, HI, CGR (grain filling period) and sink weight have been found to directly influence biological yield, their indirect contributions are relatively higher through N-uptake s alsi ot I .interestin g that sink volume which show a significans t positive correlation with biological yield, tend o displat s a direcy t negative effec n biologicao t l yield. However, it contributes positively through total N-uptake, sink weight and CGR (whole duration). N-uptake is again positively correlated with LAI and NR activity. Fro n overala m l analysis s explicii t i , t that total N-uptake o traittw e sth tha e tar contributR abilitCG d an y e moso t t biological yield directly and indirectly through other components. Hence, increased biological yield depends on the simultaneous direct and indirect improvement of its components. Path analysis of grain yield reveals HI to exhibit the maximum direct effect while total N-uptake, CGR and sink weight largely contribute through indirect effects (Table VII). The indirect contribution of total N-uptake and CGR (whole duration) via HI is much more substantial than their direct effect n graio s n yield. It can be inferred from the observed relationships that N—uptake and CGR together contribute more to the build—up of biomass during pre— and postflowering periods, consequently leading to efficient translocatio f photosynthateo n r graifo s n development. Findings of Murata(45) Weiban (46l a n (47Yoshidd t )Ah e kan )d an atha t carbohydreates synthesized after flowering were predorainently translocate d Murtf Vinayan o e sini yd th Ra aan k (38 o t d ) that N-uptake coupled with its indirect influence through LAI, contributed markedly to gain yield, lend support to the inference drawn above. The present investigation deviates from the customary path analysis of yiel f morphologicao d t usinse a g l component d revealan s w ho s various other physiological attribute e relatear s graio t d n biological yield d interrelatean s d among themselves. Grain filling period

174 for instance, while showin a gdirec t effect s beeha , n founo t d contribute indirectly mor o grait e n yield througd sinan kI H weighth . Thi s expectedi s s a ,prolonge d grain filling phase means more duration for translocation of photosynthate to grain, resulting in high grain weigh d increasean t . SinHI d k weight, apart fros direcit m t effect s beeha , n foun o contributt d e d totaindirectlan I lH N-uptakea vi y . This can be explained on the basis that depending on the demand of sink for more food material, the source is geared to synthesise the demanded quantum by enhancing nutrient uptake ability and photosynthetic efficiency (27). Fro n overala m l analysi s beeha nI H sinferre e majoth s ra d déter- minent of grain yield. The inference is based not only on its maximum direct effec t alsbu to froe findingth m s tha a majoritt e componentth f o y s contribute substantiall e modo graiTh t f yinfluenco e . n HI yiel a evi d and. relative contribution afvarious component attribute o yielt s s i d schematically represented (Fig. 6). Thus, biological yield and HI together seem to determine grain yield potential. However, high HI per se^ for the plant community does not, guarantee high grain yield per unit area. Similarly, also, high biological yield doet alwayno s s imply high grain yields. s obviouThusi t i , s thar realizinfo t g high grain yields a ,balance d improvemen f boto t h parameter s essentiali s . Biological yield contributes predominently by CGR and N-uptake. To improve these I thao componentsLA tw td s a determinan R R e CG roleNA th , e f o th se well as that of N-uptake ability and N-availability must be considered. e foregoingBaseth n o d e possiblth , e way whicy b se parameter th h s biological yield, gain yield and harvest index, could be of use to breeder e indicatear s d below.

) i Varieties with high biological yiel r hig o dI woul H h d form valuable parental material in breeding programme, ) Breedinii ge evaluateb line n ca s n termi d f changeo s n biologicai s l yield and HI at high population densities and high fertility conditions.

and

iii) Biologica n servca s earlla I e H yiel yd an generatiod n selection indices.

175 TABLE 1. LIST OF PLANT VARIANTS USED IN EXPERIMENTS RS'^TIKa TO E ESTIMATIOTH VARIATIOF NO NATURR NFO CHARACTEF EO R ASSOCIATION ESTIMATIOBETWEEE TH D NAN RELATIVF NO E CONTRIBUTION TO BIOLOGICAL AND ECONOMIC YIELDS OF VARIOUS PHYSIOLOGICAL CHARACTERS S. Ace.No./Name of Source Salient features variete th . y No

Jarabal. 1 l Mutant -L « A * j\ • X » An induced dwarf mutant from New Delhi traditional tall scented variety Jaraball from Assamerecs ha t .I and green leaves with late senescence. Panicle is compact and erect with very small sized anthocyanin pigmented grains, t 2. Manipuri Mutant -do- An induced mutant frovariete mth y Mahipuri. It is short statured plant type with long broad, droopy leaves. Profuse tillering Grains are long slender.

. Centra3 l Africa • Jg L « \ *1 \ f Vr« f X-ray induce dwile dwarth d n fi Mutant (CAM) Cuttack ric . rufipoqgneO dwarfs i t I «. Culms~"are strong with purple coloured bas apiculusd ean . Fine grains. . CR4 M 8-5711 —do— An induced dwarf mutant from Basmati 370 with slightly open plant type àeavee .Th e sar slightly droopy and green in colour. Grains are slender/ scented and awned. ^ . Boegi-Imbe5 ^ Indonesia Tall javanica cultivar with stijdy (I.R.R.I.) culms and the basal is pigmented. Its leaves are green/ JLonq and spreading. Grains have pigmented p and- ti purple awns. . Boegijrïmb6 a Dwarf -do- An induced dwarf from the above variety, having broad/ long and green leaves with semi erect plant type. Grain withoue sar t pigmentatio witd nan h reduced awns. 7. Mahsuri Malayasia A tall variety of indiea X lano- nica origin developed an n di introduced from Malayjsia. it has long/ green and thin leaves with semi-spreading habite .Th culm stiffe sar . Mahsur. 8 i Mutant-1 IARI Short statured, erect plant type New Delhi with t'.prigh greed tan n leaves M.M.D. 9 I fS APAU, Sh A selection from Mahsuri Bapatla(AP) mutant; dwarf with green leaves.

176 Tabl contd..e1 .

10. M.M.Df S17 A.F.A.U. A selection from Hahsuri Mutant, Bapatla dwarf/ slightly highe hsighn ri t (A.S.) than M.M.D Erec. fSi t inhabit with green leaves. 11. M.M.Df S18 -do- It is also a selection from Mahsuri Mutant slightls ha t .I y wider leaf angle thasistes it n r selections. 4 4 G M . 12 C.R.R.I. inducen A / d varietmutane th f to y Cuttack K 115, short statured plant type with cleistogemous flowers. 13. MG 45 -do- An induced mutant isolated from 1039H ultrs C i t a.I dwarff having thick, broad, dark green leaves with late senescence. Grains are small. 9 1 G M . 14 inducen A d-do mutan- t isolated from CH 1039. It is short statured and productive with semispreading type of eaves. 103H C . 9 15 -do- Tall variety with semispreading plant type. Short duration and cold tolerant. Leaves are long and green with wider leaf angles. 9 1 G M . 16 -do- An induced dwarf of CH 1039. Productive mutant. Leaves are green and semi-erect in nature. 17. MG 63 inducen A d-do tal- l mutant isolated from CH 45. Partly rolled and arched leaf mutant with relatively wider leaf angles. 18. MG 85 inducen A d-do dwar- f isolated from CH 45. Grains are bold» 3 7 G M . 19 alss i inducen ot a I d -domutan- f to . LeaCH45 f angle lese sar s than a s i t I . 85 G M d an 3 6 G thaM f to chlorina, productiv semd ean i tall mutant» 20. MG 39 -do- An induced dwarf mutant of CH 45 and proactive. Leaves are upright and especially flag leas fha closer angle« 21. MG 60 -do- An induced semi tall mutant isolate dSemispreadin. 45 fro H mC g plant type«

177 Tabl contd.e1 .

9 6 G M . 22 C.R.R.I Productive, semidwarf induced Cuttack Erec. 45 ntutan tH C planf to t type. Grains are fine. 23. MG 87 -do- Semi tall induce mutan5 4 H dC t with prostrate tillers. 24. CH 45 -do- Tall variety with erect plant habit. Leaf angle slightle sar y wider. 4 3 G M . 25 -do- An induced medium tall mutant from CH 45. Spreading plant type with semiJspreading leaf disposition. 26. MG 38 -do- Dwarf and productive induced mutant isolated. 45 fro H mC Erect plant type. 27. IARI 5901-2 IAR Iuprighn a s i tt I spontaneous New Delhi dwarf mutant collected from Assam. Leave dare sar k green and narrow. IAR. 28 I 6579 -do- spontaneouA s dwarf collected from Assam with upright dark green, glabrous foliage and shy tillering habit. Short slender grains. IAR. 29 I 10061 -do- Short statured spontaneous collection from Assams ha t .I dark green, upright, glabrous foliage with stems having purple pigmentation at their base* Profuse tillering type with long panicles, medium slender and scented grains. . IAR30 I 73128ÉJ -do— Spontaneous dwarf from Assam. It has sturdyK culms with dark green and upright leaves. Grains are long bold. 31. IARI 10560 -do— A spontaneous semidwarf culture collected from s Assamha t I * sturdy culms and dark green/ broad and upright leaves. Erect habit. Grain mediue sar m slender. 32. BPI 76-1 Burea Planf uo t Semi—tall variety with broad, Introduction, dark gree droopd nan y leaves. Purple pigmented sted man apiculus higs ha ht .I crud e content.

178 Tabl continuee1 d

1 2 3 4

33. Bellepatna U.S.D.A. Semitall, stiff stemmed and shy tillering cultiver with long broad/ thick and dark green leaves. Leaves are dooopy and glabrous. 34. NDC 89 IRRI Short statured variety with (B541-kh-*9-3-4 HB546) Philippines erect plant type. It has broad dark green and upright leaves» Profuse tillering type with high yield potential , Centur. 35 y Patna U.S.D.A Semitall, stiff strawed and 231(CP 231) shy tillering variety with long/ broad/ dark green, gla- brou thicd san k leaves. Grains are long slender. 36. Improved Sabarmati •IARI Dwarf/ high yielding variety New Delhi developed from the cross(T(N)l BasmatX i 370 Basmat)X i 370/4), dars Itha k green, broad dan upright leaves. Grains are long slender with basmati aroma. Possesses high crude proèein con-tent. 37. Dee-geo-woo-gen Mainland Spontaneous dwarf mutant iso- (DGWG) China lated in the variety Wu-gen. (IRRI) Ideal height with upright habit sturdy culms and,profuse tillering. Grain lone sar g bold« 38. Pusa 317-2-11-1 IARI A dwarf derivative of the cross N.Delhi between Jarabali Mutand tan NP 114. It has stiff stem, profuse tillering/ broad/ thick dark green and upright foliage. Pus. 39 a 317-2-7-1 -do- Sister selectio above th ef no culture. 40. Mutant Basmati 370 PAU An induced dwarf mutant of Kapurthala basmati 370; semierect plant type with profuse tillering. Leave greene sar , narrod wan semispreading. Grains are long slender. 41. MG 29 C.R.R. inducen A I d semidwarf chlorina Cuttack mutant isolated from CH 45. Erect plant type wity hsh tillering.

179 Tabl contde1 .

42. MG 68 CRRI Cuttack Short statured, inauced mutant isolate dGrain. 45 fro H smC are superfine and thé plant type is erect. 43. IR 480-5-9-3 IRRI Short statured plant type with Philippines erect and dark green leaves. It has high water USG efficiency. 5825-41-2-PR I . 44 1 -do- Dwarf, erect plant type with dark green leaves alst .s I oha high water use efficiency. 4432-28-R I . 45 5 -do- Erec shord tan t statured plant type with dark green and upright leaves. 46. IR 8 -do— Semidwarf, high yielding variety developed fro crosma s between Pet erec s DGWGaX ha tt .I leaves with good early seedling vigour. Erect plant type with v/ide adaptability. 0 3 R I , 47 -do- Dwarf and erect plant type. High yielding with medium early duration crosa s i s t deri.I -" vativ5141-102-6-3/IR214R I f eo 7 characterized with early seedling vigour. 6 3 R I . 48 -do— High yielding, dwarf statured. Plant type is upright. It is crosa s derivativ 1561R I f eo - 228/I 4/0.niv.///CR94-134 R2 . 49. IR 42 -do- Short statured plant with erect crosleavesa s i s t .I derivativ 1561-228-1R I f eo - 2/IR 1737//CR 94-13. 50. IR 5853-118-5 -do— Dwarf plant with upright leaves High yielding crosa s i s t .I derivativ SAGUM NA If eo 19/IR 2071-88//IR2061-214-3- 6-20.

180 TABL ESTIMATE. II E RANGF SO E GENERAL MEAN(GM), GENOTYP1C (GCVD )AN FHENOTYPIC (PCV) COEFFICIENTS OF VARIATION AND HERITABILITY (BROAD SENSE) FOR DIFFERENT PHYSIOLOGICAL CHARACTERS

Character Range GM GC) V(% PCV(%) h2 (%)

1 2 3 4 5 6 Biological yield 512.25-1704.70 1304.85 20.95 20.99 99.68 Grain yield 158.80-755 .90 536.33 28.76 28.78 99.85 Straw yield 353.45- 979.54 868.52 16.31 16.37 99.25 Harvest index 31.00- 46.70 40.33 10.65 10.66 99.72 Days to flower 70.00- 130.00 99.10 15.35 15.37 99.71 Day maturito st y 96.00- 155.00 127.48 11.56 11.58 99.58 Grain filling period 21.00- 35.00 28.38 12.49 13.09 90.99 Sink volume/plant 6.329 34.83 20.61 36.10 36.34 98.69 Sink weight/plant 5.11- 33.37 19.33 33.87 34.13 98.46 Test grain weight 7.43- 29.00 21.06 22.36 22.38 99.86 Effective tiller no. 4.60- 12.40 8.13 16.42 16.97 93.60 Biomass accumulation: Seedling 1.14- 5.71 3.12 36.50 36.57 99.66 Tillerin . 289.62g- 747.27 526.45 22.21 22.28 99.42 Flowering 430.38-1P50.97 930.98 21.59 21.64 99.58 Crop growth rate: Seedling-tillering 6.35 14.52 9.83 19.82 19.96 98.56 Ti ).lering~f lowering 9.61- 48.11 20.84 33.73 34.85 98.14 lowering-maturity 2.73- 30.26 13.36 43.61 43.86 98.84 Vhole duration 5.07- 14.210.200 17.18 17.28 98.88 Leaf area index: Tillering 2.60- 7.24.804 23.20 83.32 98.93 Flowering 3.48- 9.00 6.39 22.32 22.34 99.85 Maturity 0.75- 3.89 2.12 37.99 38.03 99.75 Net assminilation rate: Seedling-tillering 0.06. 0.28ÄS 0.133.22 3 33.42 98.89 Till ering-f lowering 0.01- 0.07 0.03 34.51 34.83 98.15 Flowering-maturity 0.0(D— 0.09 0.03 51.23 51.48 99.00 Leaf area ratio: Seedling-tillering 0.42- 1.250.84 19.90 22.26 79.87 Tillering-f lowering 0.56- 1.15 0.79 17.28' 17.51 97.38 Flowering-maturity 0.23- 0.650.35 28.19 28.35 98.83 NR activity: Seedling 1110.00-2QOO.OO 1523.00 11.52 11.84 94.78 Tillering 346.00- 784.00 511.63 15.07 15.74» 91.68 Flowering 98.89-344.44 177.99 27.69 28.63 93.56 Maturity 18.52-105.93 58.12 34.44 35.45 ' 94.34 Nitrogen uptake: Seedling 0.03- 0.19 0.08 45.03 45.32 98.69 Tillering 3.58- 10.56 6.77 24.22 24.32 98.53 Flowering 3.98- 13.64 8.72 26.30 26.50 98.55 Maturity 6.66- 15.13 10.66 25.96 26.23 98.00 Grain 2.49- 11.79 7.54 30.90 31.10 98.73 Straw 1.84- 4.26 3.11 19.83 21.04 88.81 Leaf angle at flowering: Flag leaf 1.50- 90.00 22.37 75.53 75.61 99.80 1st leaf 9.00- 49.50 21.86 48.91 49.06 99.40 2nd leaf 11.50- 51.00 23.19 42.77 42.91 99.35 3rd leaf 13.00- 55.00 26.47 38.68 38.85 99.10 Culm angle 9.40- 68.33 15.04 54.67 54.71 99.85

181 TABLE ni. PROMISING DONOR SOURCES FOR DIFFERENT PHYSIOLOGICAL A BUTES

Character Promising genotypes(bes fivef to ) Biological yield IR30, IR480-5-9-3, IRS853-118-5, IR4432-28-5, 1RS Grain yield IR4432-28-5, 1RS, IR30, IR430-5-9-3, Imp. Sab armâti Straw yield IR30, IR5853-118-5, IR480-5-9-3-, IR42, IR36 Harvest index Imp-.Sabarmati,NDC89, IR8, IARI5901-2, IR4432* 28-5 Growth duration MG19> CH1039,MG45,MG87,MG44 Grain filling period IR30,KG68, IR480-5-9-3,Mahsuri Mutant, MM.Df Sl? Sink volume Bellepatna,Pusa 317-2-11-1, BEI76-1, Imp.Sabarmati, IARI10560 Sink weight Imp.Sabarmati,IR4432-28-r5,MG29,Pusa317-2-ll- 1/IR480-5-9-3 Test grain weight IR 480-5-9-3, Boegl-Imba dwarf, MG29, MG44, Imp a.S b armâti Effective tiller number MG87,CH 45,Pusa317-2-ll-l,Imp.Sabarmati, MG34 Crop growth rate: Seedling tillering MG68,IARI7312B,MG34,IARI10560,MG 18 Tillering-flowering IR480-5-9-3/IARI10061,Bellepatna,IARI5901-2, Flowering- IR36, IR*2, IR30, MG69, IR5853-118-5 maturity Leaf area index Tillering Pusa 317-2-11-1,IR 480-5-9-3,Jaraball Mutant, CH458 ,IR Flowering Manipuri Mutant,CH45, IR8,Jaraball Mutant, IR4432-28-5 Maturity Jaraball Mutant, CH 45, Manipur Mutant NDC89, MG19 Net assimilation rate: Seedling-tillering MG18,MG34, MG45, CH1039, MG68 Tillering-flowering Bellepatna, MG19,IR480-5-9-3, wG73,BPI 76-1 Flowering ^ " " _ maturity IR42, IS36, IR30, MG85, IR5853-118-5 Leaf area ratio: Seedling-tiller dug IR 480-5-9-3, CH45, Jarabali Mutant, IARI 5901-2, MG39 Tillering-flowering Jarabali Mutant,CH45,MG39,MG60,IR480-5-9-3 Flowering-maturity MG45, CH45, Jarabali Mutant,MG19,Manipuri Mutant NR activity: MG45, Jarabali Mutant 76-1I ,BP , IR480-5-9-3 Imp •Sabarmati N-uptake; Seedling MG85,IR8,IK480-5-9-3,IR5825-41-2-P1,IR4432-2 23-5 Tillering IARI7312B,IARI10560,IR42,Imp.Sab,Pusa317-2-ll-l Flowering IR480-5-9-3,BPI76-l/IARI5901-2,Imp.Sab. IARI7312B Maturity IR480-5-9-3,Imp.Sab./IR30/IARI5901-2, M.M.Df S18 Protein content: BPI76-l,MG45,Imp.Sab.IR480-5-9-3, MG34 Leaf angles: Jarabali Mut.,IARI3579,IARI10560,MG45,Pusa317-2-ll-l Culm angle IARl7312B,M.M.Df S17,IARI10061, Mahsuri Mut. CAM

182 TABLE IV: SOME OF THE DONOR SOURCES WITH HICK EFFICIENCY FOR MAXIMUM NUMBER OF PHYSIOLOGICAL CRu^CTERISTICS

Genotypes Imp.Dwarf varieties Sprir'zaneous & induced Dwarfs characters Imp.' IR4ÏÏCP IR

Biological yield + -H- + + + + + + + + - -I - -H + Grai + n yield Straw yield _ + + - - + + + + + + + Harves + t+ index - - + - Grain fillin- g perio+ d- — . •» - T i - ? - + - Duration Sink volume 4- «* •*• •- -«• ++ + Sink weight ++ + -H- -H - + ~ Test grain weight + -H- + + - . - — Effective tiller No. + - - - - + - Crop growth rate: Seedling-tillering + - - + + - + - Tillering-flowering - -H - Flowering-maturity - - -f - - - - Leaf area index: - - -H - - + - -H tillering Flowering •»• -H- + •«••«• + + Maturity •»• -f Net Assimilation rate Seedling-tillering - - -. + — - — Tillering-flowering- + - - - - - Flowering-maturity - - + - ' - - - NR activity: Seedling + + - - - - - Tillering -f + - Flowering + - - - -. - Maturity --.-_+ - - N uptake: - - - - + + + Seedling Tillering + - ++ - + -H- + + - + - - -H + Flowering Maturity + -H- - - - » - Protein content + + - — - -' - Leaf angle: Flag leaf + + + + + + 1st leaf +__... + 2nd leaf - - + - - + . . 3rd leaf + + - - - + + + + - Cul- m angle

•«•indicates high mean of the variety •H-indicates the first or second rank among the genotypes

183 TABLE V . ESTIMATES OF SIMPLE CORRELATION COEFFICIENTS BETWiEN GROWTH PARAMETER AGRONOMID SAN C TRAITS

S. Character No. 1. Biological yield 0.982 0.859** 0.170 0.403** 0.585** -0.528** 2. Grain yield 0.934** 0.169 0.389** 0.532** -0.509** 3. Harvest index 0.133 0.317** 0.378** -0.500*V ixCrop growth rate: S. Seedling-tillering -0.169 -0.230 '0.453** 5. Tillering-flowering 0.046 -0.193 6« Flowering-maturity -0.319** Relative growth rate:. 7. Seedling-tillering 8. Tillering-flowering 9. Flowering-maturity Net assimilation rate: 10. Seedling-tillering 11. Tilloring-flowering 12. Flowering-maturi ty Leaf area ratio: Seedling-tillerin. 13 g 14. Tillering-flowering 15. Flowering-maturity

Table contd.....

184 TABL EV CONTD. . S. Character 8 10 11 12 13 1-1 15 No.

Biologica. 1 l -0.035 0.178 -0.452 -0.047 0.1-23 0.131 -0.072 -0.572 yield

2. Grain yield -0.060 0.119 -0.455 -0.075 0.362 0.118 -0.070 -0.554 ** 3. Harvest index -0.139 0.001 -0.439 •0.131 0.217 0.050 -0.102 -0.514 Crop growth rate: ** ** ** Seedling. 4 - -0.375 -0.341 0.638 -0.189 -0.303 -0.423 -0.450 -0.089 tillering 5. Tillering- 0.807 -0.132 -0.351 0.730 0.063 0.346 0.101 -0.404 flower ing ** ** Flowering. 6 - 0.060 0.886 0.258 -0.005 0.899 0.074 0.078 -0.214 mafurity Selative growth rate: * * Seedling-. , 7 . — ' i tillering 0.109 -0.080 0.778 0.220 -0.195 -0.108 -0.177 0.298 Tillering. 8 - flowering 0.123 0,170 0.872 0.167 0.382 0.235 -0.129

Flowering. 9 - *Vr maturity -0.053 0.055 0.840 0.031 0.134 0.045 Net assimilation rate: 10. Seedling-tillering 0.116 -0.119 -0.599 -0.576 0.116 11. Tillering-flowering 0.176 0.053 -0.225 -0.324 Flowering-maturit. 12 y 0.006 -0.095 -0.408 Leaf area ratio:

13. Seedling-tillering 0.731 0.113 ** 14. Tillering-flowering 0.529 15. Flowering-maturity

' »Significan leve% 5 t lta **Significan leve% 1 t lta

185 TABLDIREC. I EV T (DIAGKAL INDIRECD )AN T EFFLCT DIFFERENP SO T PHYSIOLOGICAL CHARACTERS ON BIOLOGIOvL YIELDS S. Character 1 2 34 5 6 .? 8 9 No. ______1. Knrvast index 0.167 0.007 -0.010 O.Q79 -0.018 -0.009 0.192 0.057 0.019 2\ OrôdÔ filling oeriod 0.043 0.026 -0.004 0.030 0.001 -0.018 0.080 -0.032 0.006 . Sin3 k volume por plant 0.095 0.006 -0.017 0.119 -0.041 -0.011 0.105 -0.010 0.011 4. Sink v.'t./plant 0.101 0.006 -0.016 0.131 -0.0*3 O.ID33 «O.tkQl -O.Offll 0.015 5. Effective tiller number 0.037 -0.001 -0.009 0.069 -0.082 0,001 0.042 -0.014 0.009 Tes. 6 t grai . 0.01nwt 3 0.004 -0.002 0.038 0.001 -0.115 0.064 -0.002 -0.003 7.CGR:whole durationO.115 0.007 -0.007 0.057 -0.012 -0.026 0.277 0.100 0.010 CGRsgrai. 8 n filling period 0.063 -0.006 0.001-0.001 0.008 0.002 0.185 0.150 0.002 9. LAI: tillering 0.096 0.005 -0.006 0.059 -0.022 0.010 0.086 0.008 0.033 10. LAI: flowering 0.102 0.003 -0.006 0.051 -0.026 0.011 0.099 0.016 0.031 11. LAI: maturity -0.023 -0.011 0.002-0.025 -0.01! 0.025 -0.042 0.006 0.004 12. N uptake: tillering 0.117 0.003 -0.009 0.072 -0.017 -0.002 0.142 0.045 0.015 N-uptake. 13 : flowering 0.131 0.005 -0.011 0.000 -0.021 0.006 0.174 0.037 0.019 14. N uptake:maturity0.141 0.006 -0.009 0.076 -0.016 0.006 0.220 0.075 0.019 activityR N . 15 : seedling -0.003 0.002 -0.001 0.002 -0.003 0.022 -0.021 -0.015 0.006 16. NR activity: tillering 0.011 0.002 -0.001 0.005 0.005 0.028 -0.022 -0.007 0.003 17. NR activity: . flowering 0.010 0.005 -0.002 0.012 -0.000 0.014 0.014 -0.005 0. 02 Table conta... TABLE VI Com). Total corr.with 3. Character i:o 10 11 12 13 14 15 16 17 biological yld. 1. Harvest index 0.071 0.006 0.002 0.033 0.274 -0.002 -0.009 0.001 0.859** 2. Grain filling period 0.016 0.017 0.000 0.008 0.077 0.007 -0.009 0.001 0.251* 3. Sink volume per plant 0.041 0.004 0.001 0.026 0.181 0.005 -0.009 0.001 0.505** 4. Sink wt/plant 0.054 0.008 0.001 0.026 0.188 0.002 -0.006 0.001 0.535** 5. Effective tiller number 0.036 -0.006 0.000 0.011 0.063 0.003 0.009 0.000 0.169 6. Test grai -0.01. nwt 1 O.C09 0.0008 -0.002 -0.018 -0.019 0.035 -0.001 -0.Oil 7. CGR: whole duration 0.042 0.006 0.001 0.026 0.258 -0.007 0.011 0.000 0.862** 8. CGR: grain oo filling period 0.012 -0.002 0.001 0.011 0.162 -0.009 0.006 -0.000 0.585** -4 9.LAI: tillering 0.107 -0.005 0.001 0.025 0.185 0.017 -0.013 0.001 0.588** 10. LAI flc.werJ.Kg, o_J3£'. . 'OyODJ) o.ooi •0.085 •0.97 0.01^ 0.0*0 0. 11. LAI : /&£uRi£y* o.^'s?-Oi OS'23 -o.oo"> -^.004 -O.A32 0.010 -O.TJ32 - 0.001 -0. 125 12. H uptake:* tillering 0.062 0.002 0.002 0.032 0.247 0.011 -0.013 -0.000 0.710** 13. N uptake: - flowering 0.069 0.004 0.002 0.042 0.296 0.025 -0.340 0.001 0.830** 14. N uptake: maturity 0.071 0.004 0.002 0.039 0.325 0.016 -0.025 0.001 0.951**" 15. MR activity:n out seedling 0.023 -0.004 0.000 0.011 0.055 0.098 -0.123 0.003 0.052 16. NR activity» tillering 0.016 -0.001 0.000 0.009 0.057 0.004 -0.142 0.004 0.054 17. NR activity: flowering 0.007 0.003 -0.000 0.008 0.049 0.046 -0.082 0.007 0.090 •esidual effect: 0.029 *Significan leve4 55 lt ta **Significan leve% 1 t lta TABLE VII . Director (diagonal) and indirect effect of different physiological characters on grain yield

. S Character No. 1 2_____3 456789 1. Harvest index 0.483 0.008 -0.039 0.099 -0.014 0.007 0.145 0.036 0.018 2. Grain filling period 0.123 0.034 -0.016 0.038 0.001 -0.015 0.061 -0.021 0.005 3. Sink volume/ plant 0.275 0.007 -0.070 0.149 -0.032 -0.009 0.079 -0.006 0.010 4. Sink wt/plant 0.291 0.008 -0.063 0.164 -0.033 -0.028 0.093 -0.001 0.014 Effectiv. 5 e tille . rNo 0.106 -0.001 -0.035 0.086 -0.063 0.001 0.032 -05009 0.008 6. Test grain wt. 0.038 0.005 -0.006 -0.047 0.001 -0.096 0.048 -0.001 -0.003 7. CGR: whole _ duration 0.333 0.009 -0.026 0.072 -0.009 -0.022 0.210 0.064 0.009 g° 8. CGR: grain filling period 0.182 -0.007 0.005 -0.001 0.006 0.001 0.140 0.096 0.001 LAI. 9 s tillering 0.277 01006 -0.024 0.074 -0.017 0.008 0.065 0.005 0.031 LAI. 10 : flowerinç 0.293 0.005 -0.024 0.076 -0.020 0.009 0.075 0.010 (57023 11. LAI:maturity -0.067 -0.014 0.007 -0.032 -0.008 0.020 -0.032 0.004 0.004 12. N uptake: tillering 0.340 0.003 -0.036 0.089 -0.013 -0.002 0.107 0.029 0.011 13. N uptake: flowering 0.379 0.006 -0.043 0.101 -0.016 0.005 0.132 0.024 0.013 14. N uptake: maturity 0.406 0.008 -0.039 0.095 -0.012 0.005 0.166 0.048 0.017 15. NR activity: seedling -0.008 0.002 -0.003 0.003 -0.002 0.018 0.016 -0.009 0.005 16. NR activity: tillering 0.031 0.002 -0.005 0.007 0.004 0.024 0.016 -0.004 0.003 17. NR activity: flowering 0.029 0.006 -0.^07 0.015 -0.000 0.012 0.011 -0.003 0.002

TABLE CONTD... TABL I CONTDEVI .

S. Character 10 11 12 13 14 15 16 17 Total correlation No,» with grain yield

1. Harvest index 0.024 0.001 -0.002 0.007 0.182 -0.002 -0.006 0.001 0.934** 2. Grain filling period 0.005 0.003 -0.000 0.002 0.051 0.007 -0.005 O.Q01 0.275** 3. Sink volume per plant 0.014 0.001 -0.002 0.005 0.121 0.005 -0.006 0.301 0.543-..-* 4. Sink wt/plant 0.018 0.001 -0.002 0.005 0.125 0.002 -0.004 O.D01 0.592** 5. Effective tiller number 0.012 -0.001 -0.001 0.002 0.042 0.004 0.005 0.000 0.190 6. Test grain wt. -0.003 -0.004 -0.000 -0.001 -0.012 -0.019 0.021 -0.001 0.019 7. CGR: whole duration 0.014 0.001 -0.002 0.005 0.171 -0.007 0.007 0.000 0.833** 8. CGR: grain fill- oo ing period 0.004 -0.000 -0.001 0.002 0.108 -0.009 0.004 -0.000 0.532** 9. LAI: tillering 0.037 -0.001 -0.002 0.005 0.123 0.018 -0.008 0.000 0.599** 10. LA Iflowerin: g 0.039 -0.001 -0.001 0.005 0.131 0.019 -0.012 0.000 0.635** 11. LAI : maturity -o~.oo7 -0.006 0.000 -0.001 -0.021 0.010 -0.001 -0.000 -0.131 12. N uptake: tillering 0.021 0.000 -0.003 0.006 0.165 0.011 -0.008 -0;000 0.725** 13. N uptake: flowering 0.024 0.001 -0.003 0.009 0.197 0.025 -0.021 0.001 0.840** 14. N uptake: maturity 0.024 0.031 -0.002 0.007 0.217 0.016 -0.015 0.001 0.945** 15. NR activity: seedling 0.007 -0.001 -0.000 0.002 0.036 0.099 -0.075 0.003 0.061 16« NR activity: tillering 0.005 -0.000 -0.000 0.002 0.037 0.085 -0.087 0.003 0.091 17. NR activity: - flowering 0.002 0.001 0.000 0.002 0.033 0.046 -0.050 3.006 0.104

Residual effect : 0.014 *Significant at 5% level **Significant at 1% level REFERENCES

Radford. 1 , P.J., Crop Sei., 7(1967),171-175. 2. A.O.A.C.U965) 744-74p .p 5 3. Klepper,L.,Flesher,? Hageman,R.H.,Pland .an t Physiol.48(1971) ,580.

4. K^icemanR.H. and Hucklesby,D.P.,Methods in Entomology, 23 ( 19715» /

5. Nair/r.V. Abrol,Y.P.d Ran , Crop Sei (1977),433-442? .r . 6. Evan,H.J and Naran,A., Plant Physiol..22(>, 233-2541953 . 7. Panse,V.G. an^ Sukhatme,P.V.,Second Edn. pp.381, Indian Council of Agricultural Research, New Delhi 8. Burton, G.w. Proc. 6th Int. Grassland Congr. 1(1952),277-283 9. Hansen, C.H., Robonson, H.F. and Comstock,R.E.X2aSSX,4_8(1956) pp 268-272. 10. Fisher,R,A Yakes,F.(1967)d .an , Hafnar Publ Inc.,N.Y. .Co . pp.63. 11. Wright,S.( 19?.l). J. Ägric. Res. 20 pp 557-585 12. Dewey,J.R. and Lu, K.H. (1959) . Agron. J. 5JL pp.515-518. 13. Cahndler,R.F.(Jr.) (\969),Amer. Soc. Agron. Crop. Sei.Soc.Amer. Medison, WisconsinA ,US 14. Donald,C.M.(1968).Euphytica, 17pp. 385-403. 15. Fisher, R.A. and Kertesz, Z. 7Ï976). Crop Sei«, 16 pp. 55-59 16. McEwan,J.M.(1973).Proc. Fourth Int. Wheat Genet Symp. Agric. Expt. Stan College of Agriculture, Univ. of Missouri,Columbia,

17. Rusielle,A.A. and Frey,K.J.(1977). Crop Sei. 17, pp 23-28. Jain. 18 , H.K.(l975). Proc. Internorkshow . Grain po n Legumes,pp.177-135. Donald. 19 , C.M Hamblin,Jd .an . (1976) .Adv.Agron..27 pp.361-405. Siddiq,E.A.. 20 , singh,V.P.,Zaman,F.U Puri,R.P.(1977)d .an . Annual Report, Rice Section, Divisio Geneticsf no , IARl,Hew Delhi 21. Bingham,J.(1969). Agric.Progr.44 pp.30-42. 22. Daynard,T.B. and Kennenberg,L.W. (1976) . Can. J. Plant Sei.,56 . 237-242pp . 23. Matsushima,S. and WacLa,G (1959) . Nogyo-Oyobi-engli, 34 pp303-306. 24. Mustata,Y. and Toyasi,Y. U972) . Proc. Crop. Sei.SocTJ'apan, 41 pp.372-387. 25. Yoshida.S.(i972). Ann.Rev.Plant Physiology,23, pp 437-464. . Evan,L.T.(1972)26 Ricn I . e Breeding,IRRI,Los Banos,Phillippines, pp. 449-511. 27.patil, P., Kundu,A., Mandai,R.K. and Sircar, S.M.(1976). Indian J. Agric. Sei (7)6 .4 , pp.327-337. 28. VenkateswarluTB".(1976). Plant and Soil, 44 pp 575-586. 29. borishina Okad an , . H.I,H . (1974) .Japa eed.24(5B. nJ 226-23p )p 6

Nguye. 30 n Vanwyen (1971). Acta Agronr . Acad. Sei. Hung7ÎO(l/2)ppl09-115 31. Vergara,B.S., Tanaka Yamaguchi,J.(1970)d an . ,A . Soil Sei, Plant Nutr.,16(4 141-146. )pp . 32. Oka,H.I.,Morishima,H., Chang, T.T. and Tagumpay,O( 1970) . Täter. Appi. Genets. 4^(2) pp 50-55. 33. Beovcrs,L. and Hageman,R.H.(1969)., Plant Physiol. 20 pp495-522 34. Hagcman, R.H., Leng, E.R. and Dodley,J.W.(1967). Adv. Aqron.19 , . . pp 45-83. 35. Khan, M.A. and Isunoda,S.(1970). Japan. J. Breed. 20 pp 133-140. 36. Yuan, H.F. and Shien, Y.S.tl980). Bot. Bull. Academia Sinica, 21 po. 35-52 37. Yu?n,C.M. and Sung/±aa J.M.(1980) . J. Agric. Assoc. China, 1, pp. 15-22. 33. Vinaya Rai, R.S Murty.K.S.(1979).ILRISO,28(3d .an 203-207p )p . 39. Singh, B.K. and Modgal,S.c. (1979). Plant Soir,""52.(l) pp 9-17. 40. Narasingha Rao, Ch., Sahu, G, and Murty, K.S.(l974). Indian J. Agric. Sei., 44(10) 648-652p ,p . 41. Asghasi Bano, Qua?,i Abdul Faltah and Zahced Hussein ( 1980). Indian J. PI. Physiol. 23(3) pp. 238-243. 42. Johnson, C.B., w.Nittington, W.J. and Black wood, G.c.(1976). Nature (Land) 262 pp 133-134

190 43. Abrol, Y.P. and Nair, ^.V.K. (1978) . Froc. Nat. Symp.-Nitrogen assmilatio crod nan p productivity. 44. Fakorede,M.A.a. and Heck, J.J.(1978). Crop Sei. 18, pp. 680-682. 45. Murata,Y.(1959). Physiological aspect croof s p yields, pp 235-259 46. Welbank P.J., Witts, K.J ihome,G.Nd an . « (1968 ). Ann * Bot. . 79-95pp N.S.£ 3 . , 47. Yoshida,S. and Ahn, S.B.(1968). Soil Sei. Pi. nutr., 14 pp 153-162. B10 L 06 ic AU YtBCO QRAIN 47' HARVEST i INDEX 45-

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FIG. 1 RELATIVE BIOLOGICA & GRAIL N YIELDS HARVEST INDEX IN SELECTED GENOTYPES 191 - «4- MATURITY STASE J7*«- FLOWERING STAQB !*_ T1UMINÛ. STAGE 1800 - If'

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FIG. 2 PATTERN OF BIOMASS ACCUMULA- TION IN SELECTED GENOTYPES

192 50-

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193 2000 -

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FIG 4 . NITRATE REDUCTASE ACTIVITN I Y SELECTED GENOTYPES

194 IR-490-5-9-3 fmporved sabarmati IR-36

1R-4432-28-5

-68 Jat-abali mutant

Seedling Tillerfag Flow/eHng Maturity

FIG 5 . PATTER F NITROGEO N N UPTAKN I E SELECTED GENOTYPES

195 BIOLOGICAL YIELD Leaf area index 1 NITROGEN AVAILABILITY Net ass/milatlon Crop Nitrogen rate «——— growth uptake rate NITRATE Sink, volume REDUCTASE ACTIVITY

Sink weight

Qrqîn filling period.

FIG. 6 SCHEMATIC REPRESENTATION OF PHYSIOLOGICAL PATHWAY OF GRAIN YIELD GENETIC SOMF SO E INDUCE SPONTANEOUD DAN S DWARFF SO RICE AND THEIR UTILIZATION IN CROSS-BREEDING

E.A. SIDDIQ, A.R. SADANANDA, V.P. SINGH, F.U. ZAMAN Divisio f Geneticsno , Indian Agricultural Research Institute, New Delhi, India

Abstract

Genetic inducef so spontaneoud an d s dwarf theid san r usefulness in crop improvement have been investigated. Genetic analysis of Jarabali Mutant/ Mahsuri Mutant-1 and CRM 8-5711 reveals their dwarfnes monqgenie b o st c recessive appeart .I s from, studf yo allelic relationships that dwarfism in Jarabali Mutant and CRM 8- controlles 571wa 1 non-alleliy db c recessive gene*d s sdr o l whil Mahsurn ei i Mutant- doubly 1b e recessive and, *sd ^sd^. Study of multiple character associations with dwarfness in Jarâmi Mutant suggest character e groue th son f po inherio st bloca d s ta kan others independently. While leaf cuxlines controlles si geney db s showing inhibitory epistasis, panicle compactness is governed by tv/o duplicate and one inhibitory genes. Usefulnes inducef so spontaneoud dan s dwarf crosn si s breeding with popular tall varietie wels sa higs la h yielding dwarf varieties has bean investigate detailn di . Wherea slinee th som sf eo derived from crosses involving Jarabali Mutant appear promising as well—combining alternate sources of dwarfing gene, the rest arising from crosses of mutants or their derivatives with tails or iirprcvsa DGWG dwarfs combine desirable agronomic features including high yield potential. INTRODUCTION Genetic lineage study of high yielding dwarf rice varieties popularly cultivated all over since mid-sixtées shows Dee-Geo-Wu- source th dwarfinf e eo b o t cases«e n th g Ge f geno . oven e% i r90 Fearing that such genetic homogeneity for a vital character like plant type, understandably due to breeders' continuous dependence onarrona w genetic base, might lea seriouo dt s probleme th n si future, rics scientists have started lookin alternatr gfo e sources of dwarfing gene$. Genetic studies carried out at IRRI, Philippines (Chnng, 1970, IRRI 1964, I960, 1971, 1976) (1-5) India (Padma, 1975; Singh et al. 1979;) (6„7) and other countries on a large number of dwarfs of spoütaneous and induced origin reveal occurrenc dworff eo s non-allali e rareBGWb o ct o Gt . More interestingly, the findings suggest that probability of recovering non-allelic dwarf highes si r amon mutante th g f so induced origin (Singh et al., 1979) (7). Attempts to make promisinr o e us g alleli non-alleli^ can c dwarf crosn si s breeding croe th p r improvemenfo largetd havan y ,eb yielde tangiblo dn e results as yet except for the successful utilization of induced dwarfs for the development of high yielding dwarf varieties in

197 the USA (Rutger and Peterson, 1976) (8). During the last five years, highlgenàticw fe a y f premisinso g dwarf inducef so d origin and their usefulness in cross breeding have been investigated at the Indian Agricultural Research Institute. Salient findings obtained therefro reportee mar d here: MATERIALS AND METHODS Genetic analysis relating to mode of inheritance and allelic relationship confines swa threo dt e mutagen induced dwarfs viz, Jarabali Mutant (JBM), Mahsuri Mutant-1 and CRM 8-5711. Their sourc saliend ean t feature followss a e sar :

Mutant Parent Criain (source) Salient feattures Jarabali Mutant Jarabali Gamm inducey ara d Dwarf statured with (IARI,New Delhi) high erect foliage; dark green leaves with late senescence y sup er compact & short panicles with.small sized spikelets Eahsuri Mutant-1 Mahsuri Gamma-ray induced Very short statured (lARIjNew Delhi erecd an t) plant type; green leaves; normal grai panicld nan e size CRM8-5711 Basmati370 Gamma-ray induced Short statured with tCRRI,Cutback) open plant1 type; leaves are slightly droopy& green; Grain slee sar - nde awnedd ran .

three Th a dwarf mutants tailo ,d tw an s namel4 11 P yN dwarf o 93146 s f talX 2 dwar d F F-^e lan d ,th s fdwarX an f crosses were grown under normal level fertilizef so r25P: (70K )25 N: and cultural practices (15 X 15 cm spacing with one ceedling/hill)

Throug hX dwar f analysio 2 talfX F f lso crosses modf eo inheritance was determined. Allelic relationship on the' other h^nd was studied on the basis of F2 population behaviour with respect to height character in dwarf X dv/arf crosses. Classi- fication of dwarfs was done on the basis of relative height of segre~ants by grouping those measuring / 50 cm under double dwevf, between 50 and 90 cm under single dwarf and->9O ^m un<=er tails.

Pleio.trdpic behaviour of JBM was studied in F2s of Its crosse 9314«d an s4 . wit11 P hN In the stucly of the usefulness of the mutants in cross breeding, reccnbiiianto recovered from tho three types of cross combinations viz. Mutant dv/arf X tall, Mutant dwarf X Mutant dwarf, Mutent dwarf X Spontaneous dv/arf and spontaneous dwarfcx spontaneous dv/arf were evaluated in unreplicated trials for their relative performanc componentss it yieln ei d dan e .Th

198 evaluatio Pusf no a 44-33 selectio,a n frocrose mth s IARI5901-2X Irepresentin8 R g spontaneous dwar fDGWX G dwar dons fwa e thrjoough multilocation yield trials under the All-India Coordinated Progra.nme. RESULTS AND DISCUSSION 1. Inheritance and allelic relationships of induced dwarfs Segregation crossef dwarfpattere o th 2 F f so f n o viz . JBM, Mahsuri Mutant-1 and CRM 8-5711 with selected tails 9314d an 64 N P11 reveale monogenie db dwarfneso t l al c n si recessive (Tabl. eI) On-the behavioubasi2 P f so respecn ri meanf to , variance and pattern of fcequency distribution of interdwarf crosses, allelic relationships were inferred. The cross between DGWG, an established single gene dwarf and Mahsuri Mutant-1 had shown tha genee tth s controlling dwarf statur botn ei h were ncn-allali eaco ct h other (Table-II). Similar analysie th f so MahsurcrosX M sJB i Mutant-1 showe dwarM dJB f ness (single dwarf) ir.onogenicallj bt o t y dominant over Mahsuri Mutant-1 (double dwarf). ethee Onth rcrossen i han M dJB s wit 8-571M hCR 1 seeme diffeo dt r frorese manifestinn mth ti g digenic mod inheritancf eo : 6 : 9 ( e 1), an indication of additive epistasis. From the pregoing, it appears tha tCRtd dv/arfisan l 8-571M JB s likeln e 1i mwa b o yt controlle non-alleliy db c recessive genes(sd sdr ,o 2) whiln ei Mahsuri Mutant- doubly 1b e recessive genea(sa sdU)d ,an • Occurrence sr-mf o e transgressive segregent bot n Directionse i hth s indicated the rol modifief eo r comple varief xo d strengths. In orde establiso rt allelie hth c relationshi DGWf po G with J3K and CRM 8-5711 and of Mahsuri Mutant-1 with CRM 8-5711 crosses among these are yet to be studied, Geneti. 2 c analysi complef so x locus associated wit dwarfnesM hJB s Mutations like dxvarf stature have often been foune b o dt associated with changes in a set of other characters either dut to multiple mutations or pleiotropic effect of major height cene(s). While studying the genetics of dwarfness in Jarabali Mutant scœilar phenomenon was noticed. The syndrome of characters that inherited together included length and compactness of panicle angle of flag, second and third leaves, spikelet size and shape, curliness, thickness and breadth of leaf/ and anthocyanin pigmentation. To knovi whether it is a case of pleiotropism or effect closf o e linkage uode str.cl ,a th inheritancf eo n o y individuae th f eo l characters was undertaken. On the basis of the frequency of recombinants recovered, the syncroms of characters was partitioned into two groups viz. (a) charactc-rs inheriting as a block (curly leaf, supercoaipact and short panicle, thick and erect flag leaf of 0-10°) and (b) characters segregating independently. Pending studies to define precisel fine yth e dwar M structurJB fe locusth f eo , inheritance of some of the characters was studied and the results obtained .ara as under: Genetics of leaf curliness and super compact panicles: Curly leaves and super compact (highly compact) panicles are two important 199 features of the Jarabali mutant* Inheritance of these characters was studie crossen wit M di induceo JB htw f so d dwarf mutants, viz. Mahsuri mutant and CRM 8.5711 aa'well. as with two tall cultivars, 9314d an 64 11 viz(Tabl P N . e III). The results indicated that leaf curlines complea s swa x character controlle basie on cy d b gene inhibitore on / — gond ean one antiinhibitory gene phenotypie Th . c segregatio P2'. nin s of crosses between JBM and NP 114, ©3146 and CRM85311;, indicated thaleae tth f cnrl.Lness then °controlles i mwa y genedb s showing inhibitory epistasis. Base thesn do e finding followine sth g genotypes have been assigned to the cultivars and mutants.

Mutant/variety Genotype Phenotype Jarabaii Mutant ii Cu Cu ai ai curly 93146 f, II eu eu ai ai Normal NP 114 CRM 85711 J i A i A Mahsuru NormaC u C_ i l I mutanI t

With respect to the super compact panicle, the segregation pattern in the F2's (Table III) indicated that this character was also controlle complea y db x genetic system frequence .Th f yo phenotypic classe v:elt fi sl 5 int(open:compact1 : o rati9 4 f oo ) thereby indicating the presence of two duplicate and one inhibitory genes. Bas-i thin o d s resul genotypee tth differenf so t parents were inferred as follows:

t! aut n t/v'a re.tv______Genotype______ghenotypi panicle___f eo > M C SupeM C Jarabal rM C compactnes ^ CM i l Mutanij st 1 " 4 11 P N 93146 , _ . . CP.M 8-5711 [> II «M cm cm cm Normal Mahsuri Mutant J ______incHicef c e Us d . 3 dwarf crosn si s breeding Considering their genetically distinct difference froe mth widely used DGWG dwarf, attempts were made to use Jarabali Mutant and Mahsuri Mutant-1 in cross breeding programme. The study included improvement of the mutants in respect of their agronomic features before using them as donor sources in cross breeding and direct use in crop improvement. Bein mutanga t -of rare stature with exceptionally upright culm leavesd san , cigar-like super compact paniclesmalo to ld san sized spikelets Jarabali Mutan choses twa improvemenr nfo t prior donos a crojn e ri us ss tbreedingoit . Crosse mutanf so t with tall varietie 114P sN identiresule a , th s 9314 a o Sond tt d - 6an ale ficatio fivf no e promisinq lines (Tabl efive IV)th e l line.Al s carryin same gth e induced dwarfing gene usée. decidedlfoune / b . "o dt y --. \ superior to JBM in respect of all yield components in genera mord lan e particularl panicln yi e lengt tesd han t grain weight,

200 Thus, improved lines have subsequently been used as alternate source of dwarfing gene by crossing with tall varieties as well as dwarfs carrying DGV7G gene (Tabl Amon. ) eV larg a g e numbe linef ro s under testin presentt ga line6 1 , crossef so s Pusa 431, Pusa 485, Pusa 493, Pusa 505 and- Pusa 518 appeared promising. Their relative yield performance is now B»eing evaluated through replicated yield trials. Direct use^p_f_Qwar_fs. in cross breeding; Though a large number of dwarfs of bor.h induced" and spontaneous origin has been known in India since the introduction of high yielding dwarf varieties,» only a beer fa n o eithes fes wha r release Mutans da t varieties (Tabl) eVI vtser o alternats a d e source dwarfinf so g gens. Among them Jagannath, a non-led r ing X-ray induced dwarf isolated from the popular long duration monsoon season variety T-14 1Orissaf o bees ,ha n extensively used in cross breeding with local tall as well as improved dwarf varieties (Table VII) resula s .A t onlshort-duratioe yon n variety viz.'Keshari' h£>3 so far been released for general cultivation. A number of late maturing cultures derived from crosses involving the mutant are, however, under advanced stages of testing under the All-India Coordinated Trials. Another important mutant seriew sno being exploited through cross breeding is Mehsuri, a widely popular Idta maturing .incîica X jappnica variety. Besides induced dwarfs, spontaneous sources, largely froN.Ee mth . Indian rice collection, suc i:\Rs ha I 5901-2, IARI 6579, IARI 10560 etc alse .ar o used increasingly at IARI and other centres in India. Intercrossing of dwarfs of varied genetic make-up; With twin objectives of generatin genetiw ne g effectivs a c e stockus r es fo dwarfj * donors as well as for evolving promising recombinants crosses among induced and/or spontaneous dwarfs have been effected at IARI. Among crosses involving induced dwarf differenf so t geneti cdwarfnessr makfo p eu , Mahsvxi throws Mutant-ha H numbena JB 1X recombinantf ro f so acceptable pl^nt type having improved agronomic features (Table VIII). Whiii assessing their potential for direct exploitation, they are used eis additional plant type gene sources in the crop improvement prorran.-nc. Crosses between dwarûjtepontaneous mucorigis a he nrarar s ea those involving dwarf/ inaucef 5o d Indiaorigie th n nni rice breeding procrrOT.ne. Nevertheless, one of the crosses between IARI 5901-2, a dwarf collection from N.2. Indian hills and IR 8, an improved high yielding variety ccirrying DGVG dwarfing gene, has led to the isolation of one of the ,rost promising lines viz. PUSÔ 44-33 (IET 5722) mediue Th m -duration cultur takts ehs n consi .tsntly firs seconr to d position during the .last tiiree yoars in ths Uniform Variety Trial — the last phase of testing under All-India Coordinated Trials. Considerin bess git t yie^d performanc severan ei le partth f so countrv particularly in the" whole of North zone, Karnataka and Kerolsoute th hn a i zone , Assa Wesd man t EasBengae th t n li Zon e (Table IX) it has now been recommended for Minikit Trials in farmers' fields). By virtue of its fine grain and good cooking. qualit woult yi d find favour wit broaha d sectio farmerf no s and consumers alike«

201 REFERENCES Chang,'T. 1 Taiwa. J . .T n Agric. Res. 19(1970)1-10 2. International Rice Research Institutes/ Ann.Rep.(1964)25-30 3» International Rice Research Institute, Ann.Rep,(1968)67-68 Internationa. 4 l Rice Research Institute, Ann.Rep.(1971)199-200 5. International Rice Research Institute, Ann.Rep.(1976) Padma,A. 6 . Geneti peroxidasd can e isoenzyme studie somn so e induced ?jid other, dwarf s in rice. Ph.D. thesis, Osmania University, 1975 7. Singh, V.?., Siddiq,E.A. and M.S.Swaminathan. Theor. Appl.Genet. 55(1979)169-176. 3. Rutger W.J-, Peterson, M.L. Calif. Agric. 30(1976) 4-6.

Table I. Segregation Pattern of height classes in F2's of four cross*--

Cross AssumeÄ ^, Frequenciej s of pheno'fcypic segre' — Dhenotvoic avions—————————————————— • P y ^ . Doubl'l y e dwôrf Single dwarf Tall (lSl:Dwar£) ,A^5V?m >c 0 9 7 (50-9 ) 0cm /"-^—"J like) (JBr Mo like)

1. M ah sure Mutant/ . . ,,, Jarabali 3îl 237 2.56 0.10. mutant 0.20 2.Jarabali mutant/ 9s6:l 17 129 154 3.87 0.10- CRM-85711 0.20

3.Jarabali A1 mutant/ 61 239 3.48 0.05. N? 114 0.10 4.Jarabali • mutant/ 3:1 78 222 0.30 0.8- 93146 0.9

202 TAQTiE II. Frequency distribution of height classes in F2 and Parents of four crosses

parent/cross Height class interva n F2'i l ) parents& cm n (i s Ï1-20 21-30 31-40 41-50 51-60 61-70 71-80 01-90 91-100 101- 111- 121- 131- 141- Mean Varia- 0 15 0 14 0 13 0 12 0 11 nee

8 6 0 6 5 2 0 2 4 2 3 1 J3K/CRM-8-571 3 0 1 61 23 300 77.47+ 381.67 9.57 " 1 3 0 5 . 64 2 5 5 3 2 3 Mahsvir 8 1 i Mutant2 3 / 75 200 71.67+ 407.67 X JBM 1.17 - 4 7 5 1 3 2 0 1 5 JBM/N?110 01 4 23 72 93 42 5 110.87+ 606.67 1.42 " ro 93146/J3M 002 6 13 19 23 16 108.5 1 01+ 4 9 0 8 7 4 29 529.67 8 1.33 " Parents CRM8-5711 4 6 81.2+ 23.16 1.52~ KP 114 280 133.7+ 8.61 0.93 93146 0 £*105 -£- f ? 0..7.9, i-fc JBM 5 5 T - * *.- *.

Mahsuri Mutant 3 7 41.3 + 7.8J Table III. Frequencie phenotypif so c segregatio2 F n ni

dross _____Curlines leaf______e th f so ^ Compactnes panicJ.f so e AssumedObserved frequencyX Assumed Observed frequenc^ X y Curly Non-curly Chen°- Compact Open typic (super} (Curly:noncurly) ratio (compact: open)

Jarabali mutant/ 3:13 63 237 1.00 15:49 64 236 0.73 93146 J&rabali mutant/ 3:13 60 240 0.56 15.49 53 242 2.81 4 NP11 Jarabali mutant/ 39:25 181 119 0.045 15.49 71 229 0.00 Mahrmri mutant

Jarabali mutant 7 23 /3 1.024 3.203:1 15.493 6 7 5 39 Table IV, Improvement of Jarabali Mutant prior to use in cross breeding

Pedigree Parentage Dura- Pl^nt Tiller Pani- Grains Test Har- tion height No. cle per pa- gr~ vest (days) (cm) length nicl n Indeai e x wt(gm)

Pusa 6 317-4-3-8. 6 8 1 Jarabal 5 14 i 9 26.10 3 21.6 51.3 Mutant/ NP 114 Puss. 317-2-7-1 -de5 14 - 86 11.6 20.0 236 12.6 43.6 Pusa 317-2-11-1 5 -do14 - 94 9.2 19.2 355 9.0 43.0 Pusa 318-6-1-1 93146/Jara- bal0 7 i Mxitan 0 t14 0 18.6. 0 515 14.0 40.5 Jarabali Mutant Jarabali 145 66 9.6 14.8 216 7.0 45.9

Table V. Advanced Breeding lines involving Jarabali dwarf Mutant

Pedigree Parentage Duration Salient features

Pusa 431-1-1-1 -1-1-1-1 Pusa 0 318/TKM13 6 Long slender EIOCÂ Pusa 431-1-1- 1-1-1-1-5 13 2 -do- -do- Pusa 431-1-1-1-1..1-1-3 -do- 130 -do-

Pusa 4»5r14-l~3-2..1-l Pusa318/Muskan 135 Long slender, 511553 aromatic ^AÎT .-14-1-3-2-1-2 -do- 135 -do- Pusa 465-14-1-3-2-1-3 -do- 130 -c?o- Pusa 485-14-1-3-2-1-4 -do- 130 -do- Pusa -lSS-10~l-2-l Pusa388-4/Pusal67 125 -do- Pusa 5C5-2-1-1-1 5 Type£/Pus12 7 a31 ë&o- Pusa 505-2-1--1-3 5 12 -do- -do- Pusa 505-2-1-1-4 5 12 -do- -do- Pusa 513-1-1-1 Pusa388-4-2/Pusa 0 13 7 16 -do- Pusi 51C-1-1-2 -do- 125 -do- Pusa 513-i-?.-3 -do- 125.-do- Fusa 51S-1-1-4 -do- 130 -do-

205 Tabl Lis. eMutanVI f to t Varieties release Indin di a

Mutant and hybrid mutant varieties1 Harne Yea releasf ro e Salient features (parent) 1Jagennat. h 1970 Semi tall, .fertiliser responsive (T.141) and high yielding 2. Indira 1980 Early, dwarf & high yielding (T. 65) 3.K4 8 . 1968 (T. 65) Indica grain Mutant

8 4 T 4.H 1972 One week earlier than IR 8* (IR-8) fine grain 5 .HT 60 1972 One month earlier with sc^me (IR-8) yield potential like parent -, 6 »Hvbrid Mutant-95 1973 Early maturing/ dwarf and high (Jhona349XT$Njl) yielding Irradiated 7 .Satari (NSJ200XPadraa) Very early maturing Irradiated

Table VII, Promising varieties/elite lines derived from crosses involving the dv/arf Mutant variety Jagannath

i-iutant Cross combination Variet r yo Remarks elite lines derived 1)Jagannath Kuma JagannatrX h variety da Keshar5 9 y i with Ms grain; ^ Released in 1S80 MNP36 X Jaqnnath CR236-63 Under AICRIP ^ (IET 7290) Trial Mahsur JagnnatiX h BPT3402(IET7245) -do- SuphalaXJngannath OR173-1-KIET7179) -do- PonkajXJagannath CR210-1009(IET5897 & IET 6272) -do- T.141X£.141 Mutant O1280-5(IET7135) -do-'

Source: AICRIP Annual Report 1980

206 Table VIII. Performanc derivativef eo Jarabalf so l dwarf/H^hsuri Dwarf Mutants

Pedigree Parentage Duration TMler Grain/ Test Grain No« panicle weight (gm)

PUPS 511-1-1 Hahsuri Dwarf 145 10 165 17.5 MutanVJarabali Dwarf Mutant Pusa 511-1-2 -do- 140 10 165 17.0 Pusa 511-2-1 -do- 145 8 170 16.5 Pusa 511-5-1 -do- 145 8 170 17.0 Pusa 511-5-2 -do- 145 8 165 17.0 Pusa 511-6-1 -do- 135 10 160 17.5 Pusa 511-6-2 -do- 135 10 160 17.5

Table IX,; Performance of Pusa 44-33(IET 5722) in UVT-3 (Yield in kg/ha)

Year& ., Zone1 Zone 2 2 ne 3 Zone4 Zone 5 Zone 6 All Indi se?son 0

1979 5742 4018 4394 2407 2912 5084 4655 kharif (1) (3) (2) (3) (8) (4) (1) 1980 4748 2972 4680 1698 3828 5609 4485 Kharif (5) (9) (2) (6) (4) (1) (2)

Figur paranethesin ei s indicate szone th ran en ki *Mean of -46____locations

207 THE USE OF SEMI-DWARF MUTANTS AS BREEDING MATERIALS IN RICE*

P. KHAMBANONDA, P. POOKAMANA, A. SARIGABUTR Rice Division, Departmen Agriculturef o t , Bangkok, Thailand

Abstract

Thailand's wor n induceo k d mutatio n rici n e breeding began i n 1955 using traditional ta] 1 varieties which were deficient in blast resistance. Over the years, the work has evolved through a series of change o inductiot s f mutanto n r improvinfo s e higth gh yielding varieties. In 1981, efforts were begun to induce and identify semi-dwarf types from some of the popular traditional tall varieties. The objective was to identify new sources of semi-dwarfness different from the DGWG gene which is presently used in most of the world's new rice varieties. Mutants have been obtained from three popular Thai varieties which are significantly shorter in height than their parent variety. Crosses have been made back to the parent variety and to RDI and IR36 to conduct a genetic analysi e heighth f sto genest availablye t . no Date ar a but some Fl generation plants have been transplanted in the field. Result f 1982e expecteo ar s d e availabl.b en o e Mutantdt th t a e s from the variet 9 appeare2 A L y d especially promisin d wergan e also crossed with other varieties and experimental lines for use in the conventional breeding program.

Introduction

Thailand has a total rice area of about 8 million hectares which annually produce millio5 s1 betwee d an n 4 n1 ton e pastf paddyo sth n ,I . breeding efforts were mad o collect e t farmer's varieties d purifan , y the y purb m e line selection. Almost ninet r cen pe yf Thailand' o t s rice crop is devoted to tall (about 1.5 to 2.0 meter height) photoperiod sensitive, weak-strawed, varieties which are mostly susceptible to common insects and diseases. Thus, yields tend to be low. Also, these traditional types show a relatively poor response to the addition of large amount f nitrogeo s n fertilizer,since lodging occurs beforr o e shortly after flowerin y therebma d an gy reduce yields. The rice breeding program in Thailand is aimed at producing disease and insect resistant varieties which possess high yield potential and acceptable physical and cooking quality of the grain both for domestic and export markets. With the advent of the semidwarf materials from Taiwan and IRRI, the Thai breeding program had a new challenge. The introduced semidwarf types have been widely use o combint d e their high yielding ability and wide adaptibility with the desirable characters of Thai varieties. Froe cross-breedinth m g program, high yielding semidwarf varieties were released, starting with RDI, RD2 and RD3 in 1969 [5] and these releases have progressed to RD10 (glutinous) and RD25 .^non-glutinous). At its inception in 1955, rice mutation breeding practiced with the objectives of inducing high yielding ability, short-stature, and blast

Supported by IAEA under Research Contract No. 2839/RB.

209 resistance in the traditional tall recommended varieties. Efforts were not very e lacsuccessfu th f improveo ko t e ddu l screening techniques and clearly defined breeding objectives which concentrated exclusively on tall native varieties [7] .n 1965I , co-operation began betweee th n Rice Departmen e Ini_ernationath d an t l Atomic Energy Agency (IAEAn )i Vienna. In 1968, the breeding objectives were modified to include improvement of one or a few qualitative characters present in the new semidwarf line d varietiesan s . Wor s alskwa o continue n improvino d g the traditional tall varieties t morbu , e emphasi s placeswa n selectioo d n for early maturity, glutinous endosperm and shorter height. Through induced mutation, 3 rice varieties were released in 1977, 1978 and 1981 named RD6, RD1 RD1d 5an 0 respectivel yn additio I above(Table w th . ne o I) et a ,n approac s begu wa hn 197i n 3 whereby promising mutants were use s parenta d s e cross-breedinith n g program. Several outstanding mutant linee ar s presently in the advanced trails for testing their yield potential.

The development of short-statured, stiff strawed, nitrogen responsive semi—dwarf varieties has led to substantial yield increases in many rice- growing areas. At present, only one semidwarfing gene source exists. This gene originates from Dee-geo-woo-gen (DGWG), is extensively used in the breeding programs of many countries. The DGWG gene was assumed to be in about 80% of the crosses, analyzed for 1974-1975 in 7 Asian nations [4]. This wide use creates a risk in terms of vulnerability towards pests, disea- d othean rs se hazards. Inheritanc e DGWth G f geno er semi—dwarfin fo e s ha g shown that the F2 cross of tall with semi-dwarf parents segregated 3 tall: 1 semi-dwarf indicatin contros it ga singl y b l e recessive gene [l]. Later studies also showed thae recessivth t e genr short-staturfo e n i e DGWG, Taichung Native [1] and I-geo-tse were allelic [2].

w projecne A t betwee e Ricth ne Divisio d Internationaan n l Atomic Energy Agency (IAEA) in Vienna, Austria was begun in 1980 to obtain semi-dwarf mutants from indigenous Thai varieties. The aim is to identify and make availabl w sourcene e f semidwaro s f crossn plani e t-us typr fo e breeding programs. Induced mutatio y creatma n e some alternative sources of semidwarf types, which might provid a differene t genetic makeup from DGWG and increase the opportunity for rice breeding improvement. In California, nine semidwarf rice varieties have been released which occupy as much as 9570 of the area in 1981. Mackill and Rutger £8} found two non-allelic semidwarfing genes, sd_ and jsd, other than scL which was allelic e DGWtth oG source. Futsuhar 3 als£§ ao reporte usefuo tw d l semidwarf genes that were non-alleli DGWe th G o genet c . Thus far ,e shor th nos tf o t culmed mutations were induced in Japonica cultivars [6].

Results and Discussion

During the period 1965-1973, several tall traditional rice varieties were treated with ionizing radiatio x semidwarsi d an n f mutants were obtained from Khao Dwak Mal5 (KDM10 i L 105), Niaw Sanpah Tawng (NSPT Leaund )an g Awn 29 (LA 29). The parent KDML 105 variety is a popular non-glutinous type which has good yield, good eating quality and aromatic grain. NSPT has glutinous endosperm with excellent eating quality, wide adaptability and high yield. LA 29 is non-glutinous type with long, clear grain. The original varietie NSPd se stilan Tar KDM 5 l 10 Lver y popular among farmers, but LA 29 was discarded due to its weak straw, blast and bacterial leaf blight susceptibility semidwar6 e Th . f mutants were approximatelm c 0 3 y shorter parente thath t s which ranged from 130-15 . Mos0e similacm ar t r e originatth o l varietie smutano exceptw 9 whice 2 t th tA lineL h f o s

210 'show better plant typd moran e e erect e semi-dwarleavesth n I . f mutant lin'e, NSPT'65-G.U-l.1-11 endospere th , s alswa m o changed from glutinou o non-glutinoust s l semidwarAl . f mutante ar s sensitive to photoperiod and similar to their parent variety (Table II).

e 198 t th Season 1We n I e agronomith , c valu d characteristican e s of four semidwarf mutant d parenan s t varieties were investigatee th t a d Bangkhen Rice Experiment Station, o mutanBangkoktw e t Th .line f o s NSPT wert includeno e n thii d o limitest tese du td seed. Wite exceptioth h n of difference n heighi s d yielan t d potential, other character e morar r so e less similae originath o t r l varieties (Table III) e mutan.Th t line, LA 29'73-G_Co-16-6-2-l had a good erect plant type with short, narrow leaves. It was about 42 cm shorter than LA 29 and showed promise in yield potential. The line, KDML 105'65-G.U-84-338 was approximately 26 cm shorter and had a slightly higher yield than KDML 105. The introduced semidwarf mutants such as M 101, D 24, D 66 from California and Delta from France gave much lower yields due to their poor adaptation under tropical conditions higo whict hd le hsterility e 198th 2n I . y SeasonDr , foreign rice varieties were grow d comparean n d with local semidwarf varieties, advanced lines from crosse mutantf o s s with commercial varietie o promisintw d an s g brown plant hopper resistant mutants froe th m RD7 semidwarf variety. The objective was to compare the adaptability of introduced varieties. The Thai semidwarf mutants were not included due to their photoperiod sensitivity. The results indicated that the introduced mutants were very poorly adapted (Table IV).

The 5 semi-dwarf mutants have been used in crosses for genetic analyses e conventionath d an l rice breeding program mutantl Al . s were crossed bac o theit k r original parents9 semi-dwar2 A n L additionI .o tw fe mutantth , s were crossed to RDjl and IR36, which possess the DGWG gene for short height, to obtain further informatio r genetifo n c analysis.

Seven Fl generation crosses were recently transplanted. Seven additional crosses were made to be utilized in the conventional breeding program, and the F« progenies were planted in the field for plant selection work.

The respons gibberellif o e c acid (GA_ 4 semi-dwar n )o f mutant rice varietiee th line d an s s DGWG, IR8, IR3RD1d s investigatedan 60 wa . Four vials containin plant5 g eacf o s h mutant were replicate 4 timed r pe s treatment for evaluation of the growth of the second leaf sheath. Treatment consisted of 0,5 and 10 ppm of GA which was added to the water solution. Plants were permitte day6 groo r t ds fo wbefor e measuring the second leaf sheath. The response to GAjin per cent was expressed in terms of the treated/control leaf sheath length x 100.

general,thn I e mutants showe_ responsGA a d e simila normao t r l semi-dwarfs such as DGWG, IR8 and IR36. RD10 was obtained as a glutinous mutant from the semi-dwarf RDI. One exception was the KDML 105 mutant, KDML 105 65-G U- 84-338 which showed a comparatively lower response over the control hige th h r concentratioo n (Tabl . MatureV) e plant heigh f thio t s mutant s m onlshortec wa 7 y r thaothee th n r KDM5 mutan10 L t line/whose response to GAjwas similar to the standard semi-dwarf varieties.

211 Summary

In Thailand, besides conventional breeding, induced mutation has also played a significant role in rice improvement. Three rice varieties were directly release d severaan d l desirable mutant e beinar s g usen i d the cross—breeding program. Furthermore, induced mutation may create w sourcee semi-dwarfinne th f o s g gene different from DGW n ordei G o t r reduce genetic vulnerability. Further efforts are planned to induce additional semi-dwarf mutants using other traditional tall varieties which have exhibited good performance under farm conditions. If new sources of semi-dwarf genes are found as a result of genetic analyses, these will the e employe b ne cross-breedin th n i d g progra reduco t m e th e vulnerability of rice to attack by new strain of diseases and insects.

Acknowledgements

The authors wish to express their sincere gratitude and appreciation e Internationatth o l Atomic Energy Agency (IAEA) r financia,fo l assistance to carry out part of this program.

The authors are extremely grateful to Mrs. Phontong Senawong, Mrs. Prabhasri Surapat, Mrs. Pradab Vitayateerarat Misd an ,s Orapin Vatanes for their valuable hel n conductini p e test th gmann i s y aspects. Special appreciation is also extended to Dr. Ben R. Jackson of the Rockefeller Foundation for going through the manuscript and making valuable suggestions.

REFERENCES ] [l AQUINO, R.C JENNINGSd an . , P.R., Inheritanc significancd an e f o e dwarfis n indica n i ma rice variety. Crop Sei. 6(1966) 551.

[2] CHANG, T.T., The genetic basis of wide adaptability and yielding ability of rice varieties in the tropics. Intern. Rice Comm. Newslett I 4(1969)5.XV .

[3] FUTSUHARA, Y., Breeding of a new rice variety Reimei by gamma ray radiation. Gamma Field Symp (19687 . ) 89-109.

[4] HARGROVE, Y.R.,- Ancestry of locally developed semi-dwarf rice use parens a d Asian i t n rice breeding program 1974-75n i s . Intern. Rice Comm. Newslett. 33(1978) 5.

] [5 JACKSON, B.R., PANICHAPAT AWAKUd an Breeding, , LS. ,W. , performances and characteristics of dwarf, photoperiod non-sensitive rice varieties for Thailand. Thai J. Agric. Sei. 2 (1969) 84-92.

] [6 KAWAI MASIMAd , SATOan ,T. Shor, , ,I. H. t culm mutation ricn i s e induced by P32. In: Effects of ionizing radiations on seeds. (Proc. Conf. Karlsruhe 1960, IAEA, Vienna (1961) 565.

[7] KHAMBONANDA, P., SÂRIGABUTR, A., and AWAKUL, S., Mutation breeding in rice for high yield and better blast resistance. Paper presente Jakartat a d , Indonesia,10-14 October 1977. FAO/IAEA Semina n Improvemenro Ricf o t e Production through Research Using Nuclear Techniques.

[8] MACKILL, D.J., and RUTGER, J.N., The inheritance of induced-mutant semi-dwarfing genes in rice. J. Heredity 70 (1979) 335. , 212 Table I. Thailand varieties produced by induced mutation and their characteristics

(Original) New mutant Sourc & dose e Yea Photoperiof o r d Mutated varieties varietie f radiatioo s n release sensitivity characters

Khao Dawk Mali 105 RD6 Gamm krad0 2 a s 1977 Sensitive Yield increas% 23 e Glutinous endosperm Better blast and brown spot- resistance Darker chaff color

Khao Dawk Mali 105 RD15 Gamma 15 krads 1978 Sensitive Yield increase 4.6% 10 days earlier m shortec 0 1 r Better drought resistance

RDI RD10 Fast Neutrons 1981 Non- Better cookind an g 1 krad sensitive eating quality Glutinous endosperm Moderate resistance to blast

Table II. Comparison of some characteristics of semi-dwarf mutants and their parent varieties (all are sensitive to photoperiod)

Typf o e Dose in Flowering Culm Type of Lines or varieties radiation (krad) date length (cm) endosperm

LA 29'73 G2Co-16-6-2-l gamma (Co 60) 30 Oct. 25 90 Non-glutinous n LA 29'73-NF2U-9-2-2-l Fast Neutrons 2 Oct. 21 108 U 235 LA 29 (original variety) - Oct. 22 132 u NSPT'65-G^U-l-l-ll gamma U 235 15 Sept . 29 124 1 1

NSPT'65-G1U-6-l-2 gamma U 235 15 Sept . 29 124 Glutinous NSPT (original variety) - - Oct. 20 157 M

KDML 105-G2U-84-338 gamma U 235 20 Oct. 19 128 Non-glutinous n KDML 105'65-G3U-89-295 gamma 235 25 Oct. 20 132 KDML 105 (original variety) - - Oct. 17 154 n

213 liBLS III« Agronomic evaluatio characterizatiod nan f Hno D mutant checd an s k varieties grow t Bangkhea n n Rice Experiment Station n 198i 1 Wet Season.

"SJvïï! i at • ftl *4 "\ j Lin r varieteo y Source •§•£. i! • HI ti'ra' ! Designation 'tf It O *H s — O 0 effectiv e tille r t a Coleoptil e Bo . o f a o f* P« Lengt h (nmu ) M 9 "• * U29'73-G CO-46- Thailand 7 38 erect 20 90 green dark 49 1.15 erect 22 111 141 26 740 622-1 green LA29 l73NFpU-9-2-N •1 « 6 24 erect 19 108 purple green 55 1.56 erect 22 lu? 137 25 290 LA29 (original n 7 98 erect 18 132 green green 59 1.27 erect 21 108 138 29 592 variety) KDML105 «65-0,0- N 9 91 spreading 18 128 green green 65 1.36 erect 21 105 135 27 504 84—338 K) KDML105 «65-0,0- H 9 100 spreading 17 135 green green 51 1.44 horizon *1 23 106 136 30 210 -89-295 KDKL105 (original H 9 99 normal U 154 green green 52 1.49 erect 25 103 133 26 462 variety) RD 9 • 7 94 erect 15 95 green green 48 1.42 erect 25 91 121 25 166 M 101 USA 8 95 normal 7 70 green green - - erect - 51 81 .- - D 24 H 7 93 normal 6 55 green green 44 0.59 erect - 49 79 066 n 8 90 nozsnal 6 57 green green 33 0.40 erect — ..V) 79 _ Delta Franco 8 98 normal 7 61 green green - - erect - 53 83 _ _ Sz e- M a people's Republic9 95 spreading 22 118 purple green - — Irooping 20 74 104 21 2& of China m Tawian 7 99 spreading 19 98 green green 40 1.28 erect 21 84 IM 21 152 DGWG n 7 100 spreading 15 U4 green green 48 1.42 erect 23 84 il /i 22 181 IR 8 IRRI 16 97 erect 14 96 purple green 42 1.32 erect 20 87 117 22 422 IR 36 H 7 76 erect 21 94 green green 40 0.99 erect 20 86 116 20 117 TABL » agronomiAIV e evaluatio characterizatiod nan f Introduceno d mutants compared with check varietie experimentad san l lines gro t wKhlona g Luang Iu.ce Experiment Statio Seasonn 198y i Dr 2 .

1 1 *1Î» il Lin r varieteo y Designation Source ^ iO^ CbOT ^ •tj « ïi b 3~ *:i *>s yS'7 bDH 5 Hi n ru o to *o> 3-sÉ-B-U ss ^ (*••**• t 5 $3 effect ! v » tille r a t ' ö 8 No . o f i-i--*S

maturit y Isa ita X! It 11 36 USA erect n 57 green u 0.97 hozizont 3l 14 64 94 24 B S 201 H 2 1 erect 62 green 19 0.99 it 64 94 28 26 H 64 L 201 M nonnal 7 90 dark 25 1.02 21 64 94 23 80 green M5 II 3 1 erec , t 78 dark 21 0.98 n 13 64 94 27 88 1 green M9 M 2 erect1 j : 64 green 19 1.01 n 16 64 94 28 30 M 301 « nonnal 16 69 dark 21 0.98 droppin6 1 g 64 94 26 308 J green M 302 H 2 nonna1 > l 68 dark 18 0.94 n 15 63 98 26 50 to i green D 24 M erect | 14 72 green 17 0.95 lorizonta L 15 !64 94 25 81 D 66 • 6 1 erect 65 green 19 0.89 • 16 '64 94 25 59 Earliroaa * nonnal , 11 80 green 22 0.90 « 19 64 94 26 55 Coluaa a erect 8 70 green 18 0.93 Iropping 15 '64 94 24 25 Recessive tall • erect 7 77 green 19 1.03 xorizonta . 19 i64 94 23 i 24 Delta France nonnal ' 11 91 green 24 0.97 u 18 : 68 98 33 60

DGWG Taiwan nonnal 1 10 94 dark 27 1.04 dropping 2"' 4*f 75 105 26 212 ! green i TNl 4 1 , erec t" 95 green 30 1.03 erect 22 1 8 ! 111 22 256 Sze-Mu People's Republic 8 norma1 , l 120 green 37 0.05 erect 2fc*0^ II1 W6ßO 98 21 290 of China . IR36 IRRI 8 1 erect 90 dark 28 1.90 u 21 || 75 105 21 402 i green RDI Thailand normal i 16 93 dark - - n 25 106 136 27 304 green RD9 H normal 16 97 green 33 1.U u 24 86 116 25 389 RD 10 II normal 12 99 dark _ _ it 25 D6 136 30 491 green ; 1

1 f • Tab!« IV—Continued — ' ^ tp §6 ^ 1o< ^ js'Sjji ^ jjlî |j ^ o •f* .;^ a Line or variety-Designation Source c ,o Q O O f^ r 8 *$ S P t* Cf Ü Ûi is 3IJ nil IIU I g § 598 Thailand nonaal 12 101 dark - - drooping 25 91 .21 28 RD 21 green 1.05 erect 26 75 -05 25 697 N nonaal 16 112 dark 35 RD23 green n 68 98 26 tt erect 12 96 dark 30 L.Q3 22 214 RD25 green , normal 16 96 dork 25 1.06 rooping 26 86 16 30 as green 81 111 30 640 . H erect 15 1124 dark 31 1.05 erect 27 3D7 »790^08^-3-2 green n 27 106 L36 25 254 «KM> nonaal 14 green O\ (KKH 7213-7=3) . n erect 17 102 green 23 24 86 116 25 351 04-63 «68-NF U-C3/RD9 " (KKK 7213-60-2-1) green 32 0.97 N 27 86 116 28 342 C4-63 »68-.HFJÏ-G3/TO9 noroal U 105 (KKH 7213-63-3-1). 28 558 normal U 108 green 26 106 136 C4-63 •60-HF,)B-G3/flE9 (1037213-71=2-1) n 106 27 538 , noroal U 98 dark - - 24 136 C/-6VNF U-G3/HD9 green (KKH 7213-109-1-21) green - - n 24 106 136 27 494 RD 10/ER 28 . nonaal 14 94 green •* 26 106 136 30 458 HD 10/IR 28 - „ noroal 12 100 - " (SPTCB 7500L-J>IU>64-2-i4-B>l) . . .

Not*» Fron non-adapted Europea Aaericad nan n jrarietle» few plants left in the fields. Tabl v e Respons seconlengte e th th f f dheo o leaf sheat ricf ho e varietie mutand san t senldwarf line varyino st g conoentrations of GA.

Second Laaf Sheath Length Second Loaf Sheath. Lang- LinVarietd oan undeyn a Designatio n ri variousn P«SMBt Iteoponse to GA GA concentrations

0 5 m pp 0 1 0 VS 5 ppn 5 VS 10 ppn

LA 29 «73 G2Co-l6-6-2-l 2.83 6.42 6.60 227 233

3 MF'7 L9 A2 U-9-2-2- l 2.60 7.44 8.74 286 364 »65-0^0-84-33KH-5 10 X 8 3.34 4.64 5.19 139 155

KEHL 105'65-G3U-89-295 4.28 7.72 8.83 ICO 206 Dee-geo-woo-gen 2.28 6.62 8.44 290 370 IR 8 2.61 6.64 6.62 «54' 254 IR36 3.58 7.85 9.24 219 258 BD 10 3.10 5.08 6.87 164 222

217 SIGNIFICANCE OF SEMI-DWARF VARIETIES OF RICE AND THEIR EVOLUTION THROUGH INDUCED MUTATIONS*

B. BARI . MUSTAFAG , , A.M. SOOMRO, A.W. BALOCH Atomic Energy Agricultural Research Centre, Tandojam, Sind, Pakistan

Abstract

With e introductioth , f semi-dwaro n f IRRI varieties of rice there has been a substantial increase in rice production in Pakistan. These varieties have high yield potential t carrbu , y the same eemi-dwarfing gene of'variety Dee- geo-woo-gen varietiee Th . s with suc a narroh w genetic diversity are more vulnerable to insect and disease epidemics e presenTh . t studies were undertake o develont p semi-dwarfnese th n i s local varieties of rice through induced mutations progrese Th . f thao s t wor s reportedi k .

The evolution of high yielding, semi-dwarf varieties of rice was a major contribution of the International Rice Research Institute in the Philippines. With the introduction of these varieties in Pakistan as well as in some other rice growin g1960sd countriemi e , th ther n i s e was «.phenomenal increas n rici e e production overale Th . l performanc f theso e e varieties in Pakistan was so fascinating that they overwhel- mingly replaced the elite local varieties of that time within very short period (Tabl . Pt~iW1) e B tyitfain five years t-feafr almost 50$ of the total area under rice was occupied by /. variety IS6. The traditional fine-grain varieties that went out of cultivqtion under the spell of new semi-dwarf varieties include Jajai 77, Sada Gulab and Sonahri Sugdasi. The only local variety of rice that survived the impact of Semi-dwarf IHRI varieties was Basmati 370. This variety has survived s excellenprimarilit o t e du yt grain qualits it d an y

* This wor dons kwa e under Research Contract No.3119/R Internationae th f Bo l Atomic Energy Agency.

219 pleasant aroma. Although the variety Basmati 370 yields far less than variety IR6, .ye s foreigit t n markete ar s so firmly established, its conHumer preferences are so

strongl e groweryth d set f thio an s, s variety geta pre_ miu r theimfo r produc o euc t eextenn a h s t ha tha t i t

remained a major fine-grain variety tn Pakistan. The basic draw-bac e locath n li k fine-grained varieties is that they are tall-growing and have weak stems and consequently lodge badly on fertile soils. e otheOth n r hande th e d mosvariet th f an ,o t 6 yIR other high yielding varietie f IRRo s I origi e seminar - dwarf in growth sn'd possess strong stems, and do not therefore lodge eve vern o n y fertile soils. Although these varietie e doinar s inherengn a wel t lt bu now, £L. dangee cultivatioth n i r f thesno e varieties exists in the fact that these varieties have in their genetic make-u e samth p e .".serai-dwarfing gen f theio e r ancestral variety Dee-geo-woo-gen. $he varieties with such a narrow genetic base riske pronth ar e f seriou o o st e s losses due to the possible sudden appearance of new form f inseco s d diseasan t e epidemic e occurrencth r o s e of freak adverse climatic conditions mose Th .t pragmatic approach to the problem is,therefore, to broaden the genetic base of the cultivated varieties of rice, which oan be accomplished by exploring' new sources of germplasm for semi-dwarfism, or by inducing dwarfism in the local tall-growing varieties through mutation breeding. Our earlier efforte inductionth n o s f usefuo , l mutations resulte e productioth n i d f mutano n t strainf o s rice that-mature earlier (Bar d .Awan,l974)an i d an , have better grain quality (Bari ejb al. 1981). Similar work was recently undertaken with a view to inducing semi-dwarfis foun mi r local tall-growing, fine-«rain varietie f rico s e through seed irradiatione Th , progres f thao s t wor s i outlinek thin i d s report.

220 Progress of >Vork.

Pour tall growing, fine-grain local varietief o s rice (Pryza sativa L.) i.e. Basmati 370, Jajai 77, Sada Gula Sonahrd an b i Sugdasi were r thesusefo d e studies. These varieties were derived through selection r theifo s r grain quality .fro e locamth l material havd an ,e been under cultivation for the last four decades. The agronomic character f theso s e varietie givee ar s n Tabli n . 2 e Air dried unhusked grains (1158 moisture content) of the four varieties of rice were irradiated by 6uco gamma-ray d fasan st neutron n 198i s 1 fro e Seibersdormth f Laboratory of the International Atomic Energy Agency. Five hundred grain r treatmenpe s t were taken from each Variety to begin these studies. The radiation doses 0 kRa 3 f gamma-rayo d an 5 give2 d 1.0, nan s20 wer , 15 e 5 "k£a2. f fasd o d an t 1.50 neutrons2. , treatee Th . d grains were sown along with non-irradiated grpins as control material in nursery beds, and one month old individual seedlings were transplanted in the field, keeping^uniform betwee m distancc 0 2 n f o plante d betweean s n rows. Normal cultural practices were followed for the proper growth of the plants. At the time of maturity, the five first emerging panicles of each plant from each treatment were harvested separately for growing the seg-

regating M2 generation. The single M2 plants of each treatment were grown individually at «.pi ant-to-pi an t and row-to-ro n w1962i e m totadistancc plan « Th . 0 M 2 l tf o e populatio screenee b no t thas d ha tthi s yea r semifo r - dwarfnese and other desirable characters is given in Table 3. n ordeI o keet r p continuit e breedinth n i y g programme, anothef fouo t r talse r l growing varieties of rice viz. Bengalo, Pokkali, Kangni 27 and Sonahri Kangni were included for these studies in 1982. The plant population, and the radiation treatments given to these varieties were the same as for those of the previous year first^formee Th . d five panicle f eaco s h 221 plant will be harvested individually at maturity for raising the Mg generation, and single plant selections will subsequentl made b yr semi-dwarfnes fo e d othean e r desirable characters from this material. References.

Bari, G. and Awan, M.A., 1974. Early flowering mutant strains of rice. Mutation Breed. Newsl. 3î4. Bari »Mustafa. G , , SoomroG. , , A.M d Baloch.an , A.W., 1981. Pak . J Bot. : 189-19413 . .

222 Table 1. Area, production and yield per hectare of rice in Pakieten (5-year averages till 1979-BO).

! Area Producn tio Yield per hectare Year « (in '000 hectares) (in '000' metric tone) (Kg)

1960-65 1244.4 1141.0 916.91 1965-70 1480.0 1722.2 1163.65 1970-75 1511.1 2312.0 1530.01 1975-80 1 863 .6 2958.5 1570.66 1980-81 1935.3 3119.5 1611.89 1981-62 1971.6 3337.7 1692.89 Table 2. Agronomie characters of four tall growing, fine grain varieties of rice. (Data are based on the results of field experiments)

î Days to i Plant height {Number of {Panicle ÎNumber of ,'100-grain Grain yield Variety { heading ', (cm) {panicles {length {grains per {weight (g) (Kg/ha) r plantpe I , (cm) {paniclj j e j i i 1 ——— i——— —t —— — î______î——— —

Basraeti 370 119 153.0 9.0 29.3 67.6 2.18 3315.78

Jaja7 7 i 123 167.0 7 7. 24.9 73.7 2.33 3305.63

Sa da Gulab 125 164.8 7.6 30.9 76.0 2.36 3407.84

Sonahri Sugdasi 128 141.7 7.3 27.5 77.6 2.35 3328.07

Tabl. 3 e Plant population of rice grown in K« generation e foth r selectiof o n desirable characters. " • "•— —- i } Conti Gamma - rays J Fast neutrons Treatment i -oi ; t Variety t { 15 kRa 0 kRad {2 d ',25 kRa 0 kRad{3 d {1.0 kRad {1.5 kRad 1 2.0 kRadJ2.5 kRad —— .,„,„., . ,„—,.,,.,...,! . t , t , i .i «

Basmati 370 491 2211 4763 1641 1082 3688 5435 2576 871

Jaja7 7 i 496 6456 7621 4242 2625 5367 6595 1723 1855

S ad a Gulab 500 4570 4353 6583 4844 4332 10625 8436 4150

Sonahri Sugdasi 495 5622 7541 6224 3387 3792 11186 6563 947 INDUCED SEMI-DWARF MUTANTS DM UPLAND RICE* A.M. RIYANTI SUMANGGONO . ISMACHIM , N KARTOPRAWIRO, P.S. MUGIONO ApplicatioCentre th r efo Isotopef no Radiationsd san , Kebayoran Lama, Jakarta Selatan, Indonesia

Abstract

Short stature mutants have playe n importana d t rol n rici e e improvement in recent years. They have been used both directly r commerciafo l cultivation d als,an o indirectl s parenta y n crossi s - breeding programmes. Lowland rice field e quitar s e limiten i d Indonesia r increasinfo o s , e ricth ge productio s suggestei t i n d that rice be cultivated in the upland areas. New upland rice cultivars having short stature, high tillering abilit d resistanan y o higt t h fertilizer inputs are needed.

Introduction

In recent years Short stature mutants have played a significant rol n rici e e improvement. They have been used both directln i y commercial cultivatio d indirectlan n s parenta y cross-breedinn i s g programmes. Short stature mutants can be induced by radiations a sy chemica b wel s a l l mutagens [6]. Short stature mutants induced by X-rays were first reporte y ICHIJIMb d A (1934 a japonic n )i a cultivar. Then mutants from GEB-24 indica rice variety were reported by RAMIAH and PARTHASARTY (1938), FUTSUHARA (1967) reported w shorne thae t th tculm , variety Reimei, release n Japai d n i n 1966 (cited from PADM d REDDY[4]..)an A m shortec , 5 Reime1 rs wa i and showed lodging resistance and high fertility. Basmati, the scented semi-dwarf was discovered after treatment with Diethysulphate by REDDY (1971) [5]. KAWAI et al (1961) isolated more than a hundred true-breeding short stature mutant induce y radiactivb d e p 32 treatment [3] .shore th Mos tf o tstatur e mutants were inferior s regarda s change f agronomio s c character z lodginvi s g resistance, high tillering ability, responsiveness to fertilizer, etc. These trait e desirablar s o upgradt e e yielth e d potentia f riceo l . In the last decade, two short stature varieties have been developed by IRRI in the Phillippines. Most of the semi-dwarf varieties developed carr gena y e frovariete th m y Dee-Geo-Woo-Gen (CHANDLER, 1968) [2]. Genetic uniformity among widely grown crop cultivars presents a risk in terms of disease or pest epidemics. So, to avoid genetic vulnerability, new sources of short stature genes are needed. In every yeae ricth re neede n Indonesii d a increases, increasine th o (_t + e 4.57g du populatio.) 2.34%)^ ( n . According to the World Bank, it was estimated that in the five year period starting by 1985, the government shoulc increase the import of ric abouy b e 4 millioyearr 2. tpe n , to wherean n 199i s e defici0th t of rice would be about 2.9 million tons per year. But if the dry season

* Research supported under IAEA Research Contract No.3125/RB.

225 is extended or if damage from diseases takes place, the rice deficit would increase to 5.2 million tons in 1985, and to 8.3 in 1990. It s estimatewa d that world rice productio y decreas nma e yea th r y b e 2000, thus it may become more difficult tor the government to import a self-supportin r itFo . g level e governmenth , t should increase the rice production about 5% per year. However, this may be difficul o achievt t e because limitth o ricf t o se e production fields. The current production area for upland rice in Indonesia is about 1.500.000 ha, or about 1670 of the rice production area. However upland rice production per ha is less than 50% of that for lowland rice y intensivelB . y increasin e transmigratioth g n programme of the government from Java island to another island in Indonesia, there n coulincreas a e uplan e th b d n di e cultivatio f riceo nt Bu . w areathne e s usuallt havno eo d yprope r irrigation systems. Usually farmers in the transmigration areas cultivate the local upland rice varieties whic e lesar h s responsiv o fertilizert e , sensitive to diseases, tald havan l e wide leavesr almosfa o t.S nothins ha g been done about the breeding of upland rice in Indonesia. The best variety for upland was selected from a local variety collection, viz variety "Seratus Malam" released in 1960. Another variety which seems to be good for upland conditions is "Cartuna", an introduced variety from the Philippines released National in 1963. These two varieties are early in maturity, but are tall (height + 150 cm). Several breeders and agronomists indicate a preference for relatively short stature such as in 1RS under upland conditions because of the improved plant type, suc s higa h h tillering abilit d resistancan y o t e lodging[l]. It is well-known that better tillering ability is a desirable featur r upgradinfo e e yielth g d potential f uplano s d varieties.

Material d Methodan s s

In our institute(Centre for the Application of Isotopes and Radiation) wore th f ,mutatioo k n breedin n rici g e starten i d 1970 using gamma and the chemical mutagen, EMS. Formerly, we searched for early maturity and high yielding types from our local lowland varieties,[such as Pelita I/I (PI/1), developed from crossing between Syntha n indic-a a local variet d 1RS]an y , Rajalele etc. In 1976 several mutants having an early maturity and a high yielding character were obtained, but some were not released due to their sensitivity to the brown plant hopper. Some of the mutants had short stature. One of the short stature mutants, A13/PsJ/72K had been used as parent in a cross-breeding programme at the Central Research and Development Institute for Food Crops (CENTREDIF) in Bogor since 1976.

Results; Semt-dwarf Lowland Rise Mutants

Many semi-dwarf and dwarf mutants have been produced in previous programm o lowlant e d rice. These semi-dwarf mutants were first isolated in the M_ generation. In M_ some of them were homozygous and others segregated , homozygouM e Th . s mutants indicated thae th t a singl o t ee recessivdu trai s wa t e gene.

226 Mutan te semi-dwar th A23/PsJ/72 f o e fon mutants i K s from PI/1 which has early maturity and is high yielding. The F. from crossing with PI/1 and also with Syntha (tall local variety) - reciproca s tal a ls PI/ a ls crosr Syntha o 1wa - s , indicating that semi-dwarf gene, A23/PsJ/72K was a recessive gene. In contrast to this

f crossino th 1 F e g between IR30 with PI/ s semir Syntha o 1 s -wa a dwar s IR.3a f 0 (see Tabl . Thus1) e t seemi , s thae degreth t f o e recessivity or dominance may be quite relative. On the other hand, other characters might als e mutatee samb o th e t a timd e with semi- dwarf mutations.

PROGRAMME ON INDUCED SEMI-DWARF MUTANTS IN UPLAND RICE :

M. Two selected local upland rice varieties (Seratus Malam and Becal) are being used as breeding materials. The seeds were irradiated with gamma-ray doset a s f 100o s , 200, 300, 400 and 500 grays. r radiatioFo n effect n seedso s e seedlinth , g growth, chromosome abnormality, sterility plant height and maturity will be observed. Four major panicles wil e harvestedb l o wil e tw bulke,b l d an d the others will be kept^separafeely. e bulTh o paniclekM« tw see. f M„ o d n si wilw e plantero b l a s a d A very dense population will be used in M- plantations to avoid large area and to increase the efficiency of screening. Only the semidwarf or dwarf plants will be harvested separately. e seedTh s froe otheth m. paniclerM s wil e germinateb l wooden i d n boxes for observing chlorophyll mutations.

M_ Progeny from every selected M? plant will be planted as a row in M_. The true breeding mutants will be crossed to the parent for genetical studies.

EVALUATION PROGRAMME FOR SEMI-DWARF MUTANTS :

1. Blast resistance test. Blasmajoa s i tr diseas r uplanfo e d rice in Indonesia. All true—breeding semidwarf mutants will be tested for their reaction to blast.

. 2 Brown planthopper momente th test t A ,. only varieties officialle b whicn e resistanca ar hH yBP releasedo t . Therefore, all true breeding semidwarf mutants will also be teste r theifo d r reactio BPHo t n .

3. Yield potential test. The promising true breeding semidwarf mutants will be tested for their yield potential, their adaptability to locations and their response to fertilizers.

. 4 Genetic evaluation o limitatiot e Du . f facilitieo n r fo s genetic evaluation, only three mutants from Seratus Malad an m three mutants from Cartuna will be evaluated. If possible, t leasa t thtbu e , evaluatiBC d an , n F_ wil , lF« includ, F. , P e P, F1 and F- evaluation may be enough.

227 ACKNOWLEDGEMENT

e authorTh s wis expreso t h s special . Kawathankr Dr fo o it s his encouragemen d advicetan e gratefull.W y acknowledg financiae th e l assistance of the IAEA.

1. ABIFARBt, A.O., R. CHABROLIN, M. JACQUOT, R. MARIE and J.C. MOOMAW 1972., Upland rice improvement in West.Africa, International Rice Research Institute, Rice Breeding Banoss ,Lo , Philippines, pp. 625-635. CHANDLER. 2 Jr.. ,F , Dwarf ricgiana e- tropican ti l Asia, ÜSDA year Boo Agrf ko . (1968) 252-25f 3. KAWAI T., H. SATO and I.MASHIMA 1961, Shortculm mutations in rice induced by 32p. ^ effects of ionizing Radiatio Seedsn no , IAEA, VIENNA, PP. 565-579. 11. PADMAG.Md an . . ,REDDYA , Genetic behaviouf ro Five Induced Dwarf Mutants in an Indica Rice cultivar, Crop Scienc 1977c e De )Vol(No 7 1 - v. — p- 860-Ö63. REDDY. 5 , G.M., REDDY, T.P., Induced semidwarf basmathi rice mutant for commercial use, Intern. Symp. use Iso. Radi. Agri. Ani. Husb. (1977) 237-21J.1. .6. ————— Manual on Mutation Breeding, Second Edition - IAEA, VIENNA, 1977.

228 CHARACTERIZATION AND EVALUATION OF SEMI-DWARF MUTANTS IN INDICA RICE*

T.P. REDDY, K. VAIDYANATH, G.M. REDDY Department of Genetics, Osmania University, Hyderabad (A.P.), India

Abstract

The statu semi-dwarf so f rice varieties, their parentage, yield potentia othed lan r salient features are briefly reviewed. Tue limitations of these cultivars and certain possible solutions are discussed. A mutant strain, Jagannath sole th e s ,i exampl e of an induced serai-dwarf released for cultivation in India. An EMS-induced semi-dwarf (Sd4), with lodging resistanc superiod ean r yield potential, appears promisin varieta s ca summer fo y r season. Likewise, certain semi-dwarf mutants, induced in Hahsuri, ïilalcchandan, Basinati 370 and MTU 17, seem suitable for commercial cultivation. A literatursurvee th f yo spontaneoun eo s semi- dwarfs revealed the existence of, at least, three nonalleli genesD cS . Geneticd analysian 4 Sd f so five dwarf mutants of TIC revealed the presence of recessive genes tha nonallelie tar DGWo ct G locus. Similarly, inheritance studies on other induced semi- dwarfs, CAM and TR-5, indicated single recessive genes nonallelic to DGWG. Such alternative sources geneoD f S valuabl e sar guardinn ei g against genetic vulnerability ^f the rice crop. inducee Somth f eo d short statured mutantd san their parents have been characterized for their peroxidase and amylase activities at the seedling stage. infleptn A havailabl e studsemiw th ne f y o - d ean dwarf mutants, with respect to their plant architecture, agronomy, genetics and physiology, is needed for an • effective and planned use of. nonallelic SD genej in-rice breeding projects.

1. INTRODUCTION majoe Th r constraint increasina si g grain yieldf so traditional rice varieties had been lack of response to nitrogenous fertilizer lodgingd san , besides inefficient partitioning of biomass. Introduction of the high yield- semi-dwarfsg in , Taichung (Native )(T(N)11 IR-8d )an , heralded a new era of increased rice productivity £"1 J,

Research supported by IAEA under Research Contract No. 3116.

229 However initiae ,th l impac thesf to e cultivar ricn so e yields has been less impressive £'2j, as they were ill adapted to diverse agro-climatic conditions encountered rice inth e tract Indiaf so . Consequently, intensive efforts were made to breed varieties v/ith the high yield potential of T(M) 1 and IR-8 and the desirable attributes Of tall local cultivars. As a consequence, several semi-dwarf varieties have" been evolved and released for commercia semi-dv/are lth l cultivatioAl f- s. ,re J 3 n[ leased so far, have the common gene for dwarfins obtained fron Dee-Geo-Woo-Gen (DGWG). Genetic vulnerability £ 4 ] an narroa d w choic qualitf eo y majo e gradeth re sar limi - tations associated v/ith DGV/G gene. Hence it is desirable to diversif genee ydwarfisth r sfo indicn mi a rice- In . ductio semi-dwarff no taln si l varieties, besides serving as alternative sources of dwarfing genes, might offer the advantag superiof eo r grain qualit tolerancd yan o et stress conditions /"5y. This report deals v/ith the status of semi-dv/arf varieties, their parentage geneticd ,an certaif so n short- culm mutations induced in local varieties at the Osniania Universit othed yan r institutes.

2. STATUS OF SEMI-DV/ARF RICE VARIETIES AND THEIR PARENTAGE Prior to the introduction of semi-dwarf tsnpes, there were about 430 improved varieties under commercial cultivatio Indin ni a L&J. These varietie mostle sar y tall with weak culms, and tend to grow leafy and lodge even before flowering. Under good fertility conditions and the bes managementf to , their grain yields seldom exceede5 d4- tons/ha. Introductio semi-dwarf no f cultivars, d T(Nan )1 significanIR-8a s ,wa t turning rice pointh e n tculturi e of India f 7 J . These varieties highlighted the concept of 'plant typeidee indicn th i a«o that ad tricele d ,an dwarfing is the way to high yields. This plant type, having short-stiff straw, erect dark green leaves, early vigour, profuse tillering, photo-inserisitivit yrespons, e to high fertilization and high harvest index, made possible grain yields of 8-10 tons/ha under good management. The 'merits of new plant type justified a reorienta- tion of the Indian rice breeding programmes in favour of semi-dwarfs resultIndia l s Al A .ae ,Co-ordinateth d Rice Improvement Project (AICRIP) and other central and state organisations release hig0 d2 h yielding semi-dwarf cultivars through Central Variety Release Committee (CVRC). v/hile 106 varieties were released by local or- ganisation lis selecteA f o t• ] d3 semi-dwars£ f varieties, along v/ith their parentage, yield potential and other salient features, is given in Table I.

230 The variety T (N) 1, introduced in 1964, was not popular owing to its poor grain quality and susceptibi- lit diseaso yt droughtd ean Whil,. e IR-8 releasen di 196readils wa 6 y accepte farmere th y db s becauss it f eo high yield potential (9.5 tons/ha tolerancd )an * eto disease. Another semi-dwarf cultivar, Jaya, derived from T(N141T founs x ),wa 1 d superio yieln ri d dan earlie maturityn ri T.R-0,o t . However, these varieties have long-bold grains with poor millin cookind gan g qualities. othe e Mosth rf to hig h yielding varieties originated from hybridization between the traditional tails (over 200) and tho exotic semi-dwarfs (T (N) 1, IR-8) witii DGWG gene. Several semi-dwarf cultures — Vijaya, Bala, Sabarmati, Ratna, Tellahamsa, Sona, Jayanthi and others — v/ith wide variations in maturity, grain typ yield ean d potential, have been released between 1969-81 for cultivation in India. A semi-dwarf mutant, Jagannath, induce 141T n di , hybrid mutant-95 and K-84 are the only examples of mutants released for commercial cultivatio thin ni s countr. J 8 y/ Mutation breeding, thus, played a minor role in the developmen higf to h yielding rice varieties. The coverage under semi-dwarf cultivars for the entire countr estimates yi aboue b o tdt e 37/th f £o total rice area [ 3 J » Their impact on rice production has beenunainly>felt'in areas with medium fertilit d assureyan d irrigation. water-logget .Bu illd an d - drained areas account for nearly 40# of the total rice acreage; here impace ,th semi-dwarff to ricn so e yields has been relatively low. Non-lodging varietias with medium-tall stature and grain dormancy are required in these areas /~8 J. Likewise, semi-dwarf lines v/ith early vigour, maturit droughd yan t resistance, suiteo dt upland conditions (15& of rice area), should also be developed. Durin lase yearg6 th t1 s major changes have occurred in the varietal composition and cultural practices of rice production. About 150 semi-dwarf varieties have replaced hundred traditionaf so l cultivars, leadina o gt drastic reduction in the diversity of rice varieties grown in the country. Reduced genetic variability, improved cultural practices and continuous cropping have accentuate genetie dth c vulnerabilit rice th e f ycropo . Moreover,' e luxurian'th t crop e semi-dwarfcanopth f o y s creates congenial condition rapie th dr sspreafo f do insects and disease. It is imperative, therefore, that different rice varieties with alterative dwarfing genes having favourable responses to more than one stress condition shoul evolvee db stabilizo dt puso t p hd u ean the productivity of rice .

231 3. SEMI-DWARFING (SD) GENES OF SPONTANEOUS ORIGIN The precise origin of Dee-Geo-Woo-Gen semi-dwarf is not known. It is assumed that the original tall strain, Uoo-gen, was brought to Taiwan from mainland China before the Japanese occupation. Probably, a spontaneous mutation in Y/oo-gen caused the dwarfing which was selected and propagated before the turn of the century /"9 ]. The DGWG gene is unique because it reduces height v/ith otherwise normal sized plant parts. uses ITaiwantn wa di , three decades ago produco ,t e T(N) 1, and later, at IRRI, it was crossed with Peta to produce IR-8. This sourc semidwarfisf eo sincs mha e been used extensively in the development of rice cultivar Indi n elsewhersi d aan . } 2 e£ Inheritanc shorf eo t statur bees eha n studien di DGWG and another semi-dwarf line I-geo-tze. A partially recessive single gen founs ewa d responsiblr efo height reduction in these stocks /" 10 }. Genetic analysi anothen so r semi-dwarf Cheng-chu-a fro, i11 m mainland China, suggeste differena ds ha tha t ti t gene governing short plant. heigh_7 1 1 " t/ A nativtota4 1 f lo e varieties with short stature were collected from north-east India (Assam Rice Collec- tion (ARC)). Some of them exhibited good yield potential and toleranc moisturo et e stress» Genetic studien si two crosses, each between a dwarf indica (DGWG) and ARC dwarf, were indicative of the presence of a hypostatic tall gene with dominant inhibito Assao tw mre genth n ei dwarfs involved £ 12 J. The short stature of semi-dwarf Chi-nan-ai, from China, was not allelic to T(N) 1 or Cheng-chu-ai 11. On the other hand, height in two semi-dwarfs, ARC 5929 598anC dAR fro, 1A m India, proveallelie b o dt o ct DGWG gene £ 13 J. In crosse Baokf so Indonesian ,a n tall-growing (130-140 cm) rice variety, with tall native cultivars, the F1 hybrids were tall. Whereas, in F2 progenies of these crosses segregation for height occurred in a ratio of 13 tails : 3 dwarfs. This ratio was explained on the assumption that Baok possessed a gene, DD, for dwarfness an dominanda t factor whic, ,II h inhibits dwarfismn O . the other hand tale ,th l locals possess both recessive genes, ddii dware Th .f derivatives (D-ii), with dark-green erect leaves and short-stiff culms, were non-lodging. The Baok dwarf ism night be of potential value as an alternative source of short stature for future rice breeding programme. J 4 1 " s/ Identificatio alternativf no e gene' semidwarfr sfo - ism preveno ,t t genetic vulnerabilit s ofteha y$ n been emphasized /"4, 15.7» Genetic studie spontaneoun so s „emi-dwarfs revealed that leas t thera e te ar thre e non-

232 allalic genes for short stature in rice. Pleiotropic and interactive effect thesf so e gene diversn si e genetic backgrounds need investigation prio theio rt r utilization in rice improvement.

4. INDUCED SEMI-DWARF & DWARF MUTANTS OF PROMISE Mutations involving change plann si t height have beemose nth t common variants observen I îd[ . 6 J India, Ramiah and Parthasarathy /"17 } reported for the first time abe« inductioe tth dwarf no f mutant ricen si . Since then short statured mutants have been induced in tall rices by many workers. An x-ray induced semi-dwarf (BBS 873), recovereonle 141T th tal e y . s th ,li CV n di mutant released for commercial cultivation (as Jagannath) higa s hCVRCi e byieldingyt th I . , photosensitive, non- lodging variety well-adapted to low-land conditions prevailing in eastern and southern states of India [ 18 J. At the Bhabha Atomic Research Centre (BARC), several short culmed mutants were induce taln di l varieties. Mutant Baod stife an skar recovereB f 26 R S n di strawed with lodging resistance; toleranc salinito et s yi maintained in the mutant, TR-5, obtained from SR 26B. A semi-dwarf induced in Basmati 370, TR-28. seemed promising in; yield potential and quality attributes. Use of serai-dwarf mutant hybridization si n generated certain promising cultures with desirable combination of characters /"57. At the Central Rice Research Institute, Cuttack, several non-lodging semi-dwarfs with high yield potential were induce Mahsurn d i » MTU-1Chaudhard J 9 ian 1 7[ y havJ 0 2 e [ isolate l eta d some promising mutant aron si - matic rice varieties. A semi-dwarf mutant, TCA-P2-5, induced in CV. Tilakchandan, is 40 cm shorter and 25 days earlier maturing than its parent. This mutant has long- blender grains with high yield potentia tons/ha5 l( d )an is now under final stages of testing. At Osihania University a wide range of short- culra mutants were induced in tall local varieties, viz., HR 47, Tellakattcra (TK), Yerragaluvadlu (YV), Mizulu, Mahsuri. HR- othersd 5an . Base heightn do ,totaa f lo about 60 mutants were classified as semi-dwarfs (70-10dwarfd cm)0 7 an ) < .s( 5cm Som thef eo m were non-lodging v/ith better yield potential thae nth parents [ 21 ]. aromatie Inth c short-staturevariety0 , 47 R ,H d mutants were recovered after diethy1 sulphate treatment. semi-dwaro th Onf eo f mutants showed earlines0 1 y sb days, increased panicle number and superior protein content besides lodging resistance. Reductio plane th tn ni

233 height is mainly due to a decrease in the length of the panicle bearing 6th internode(peduncle) followed by reductions in the 5th & 4th internodes. Field trials conducted over locations and seasons indicated thamutane tth t yields about 15-20& more grain than the parent [ 22 ]. In TK, a tall (130 cm) indigenous variety with early maturit days)5 (9 y , several short-culm mutants were recovered after ethyl methanesulfonate treatment serai-dv;are th f o e f On mutants . J 3 2 , [ Sd4, with dark- green leave erecd san t plant type grow meaa o snt height of about 90 cms. It is non-lodging with stiff culms and has excelled the parent in no. of panicles, grain number/ panicle and grai^i yield (Table II). Furthermore, the e parenmutanth dayn s equatti i maturito so t t l d yan appears promising as a cultivar for summer cropping [24]. Height reductio somi-dware th n ni dward fan f mutantf so TK was caused by decrease in the lengths of specific internodes rather than.reduction in the number of internodes. The mutant^ however, "display marked differences in the pattern of internode elongation [ 22, 24 J.

. 5 SEMIDWARFING (SD DWARFIND )AN G GENE INDUCEF SO D MUTATION ORIGIN Mutasenesis woul profitable db inductior efo D S f no mutants in indigenous varieties with specific agronomic features suc grais ha n quality, toleranc colo ed t dan salinity, and resistance to drought, disease and insects. A large number of short statured mutants produced from local cultivars were caused by monogenic recessive mutations. Most of the mutant genes were found to be allelic to DGWG locus. However, induced mutagenesis might give rise to dwarfing distinct from those foun n naturai d l dwarfs. The semi-dwarf mutant TR-5 seems to be nonallelic to DGWG gene; whereas the dwarfing genes in other mutants crossen e proveI allelie b th • f o J sDGWd o t o 5 ct G[ semi-dwarf mutant, Jagannath, wit parene h th DGWG d tan , the F1 plants were tall. The unimodal distributions in indicate2 F d that^fehort statur mutane th goverf s eto i - pplygenia ney db c system nonalleli DGWo ct G dwarfism L 13 j'• The semidwarfisia in an induced mutant, S3, is controlled by two recessive genes that are nonallelic to DGW . StudieG7 5 gen2 es[ mad I.A.R.I.t ea , Delhi, dwarfo4 n1 s revealed tha inducen ta d mutant from Cen- tral Africa (CAM) might posses nonallelisa c dwarfing gene with equal strength of positive and negative modifiers f26J. The F1 hybrid between HR 47 and its semi-dwarf mutan talls tsegregatiowa e ;th n patter sugges2 F n ni - ted that semidwarfism is caused by a single recessive mutan . SeveratJ 2 gen2 e£ l short-culm mutants with 234 distinct morphologies were inducetale th l n indicdi a variety TK £ 24 } . The mode of inheritance and allel- serai-dwara isf o m f (Sd4 fivd )an e dv/ar, f d8 (do , ,d? d9 and d10) mutants of .TK has been investigated / 27 /. In the cross Sd4 x TIC, the F1 plants were tall. Its F2 distribution ranged' from the height class 70 to unimodas wa d naturean n li s cm .0 13 However4 ,Sd crossed with DGVG showesegregatio2 F d d an tal s lF1 n suggestin, 7 : rati9 f oo g thainvolve4 tSd majosa r gene mutation nonallelic to DGWG gene (Table III).

In crosses with DGWG each of the five TK dwarfs showed complementary behaviou talr rfo l heigh1 F n ti (Table IV) dihybrie .Th d segregatio7 nî rati9 f oo observed in F2 progenies suggests that the five dwarfing gene nonallelie sar tale 1 Th lDGWF o ct . GJ gen4 " e/ plansegregatio2 F 1 tî heigh3 d nt an ratioe th n si crosse dwarff so s wit indicatC hTI e tha dwarfe tth e sar controlle singly db e recessive genes (Tabl . CrosseeV) s among dwarfs produced tal plants1 lF dihybrie ;th d segregatio observe7 n population: 2 ratiF 9 n f di oo s suggest that these dwarfing genes are also nonallelic to eac Partia. h J othe8 2 lr[ dominanc genr e efo th f eo tallnes presencse th (TK d modifier)f an eo s influencing plant height were inferred in certain crosses of these mutant7 2 s/ The cross of TK d10 with the dwarf mutant, ed-1 , Induced in 3B-8, showed complementary interaction for plant height in F1 An F2 dihybrid ratio of 9 tails : parenta6 l dwarf doubl1 s: e dwar%0.70-0.00= P f( ) sug- gets tha mutane tth t gene nonallelie sar compled can - mentary in their behaviour /"29 J» Further, in do and d7 crosses with ed-1 , a clear segregation in F2 for tall, single dwarfs, double dwarf tripld san e dwarfs, in the ratio 27 : 27 î 9 : 1 , suggested that ed-1 may bdoublea . e J dwar7 2 f/ rapie Th d sprea semi-dwarff do s with DGWG gene Introduce e dangesth f continuouro s e:cposur same eth f o e genetic backgroun adaptatioe th o dt specifif no c pathogens CkJ. Nonallelic sources of SD genes, both of spontaneous and induced mutation origin, are valuable in guarding against genetic uniformity of the rice varieties.

. 6 BIOCHEMICA PHYSIOLOGICAD LAN L CHARACTERIZATION OF SHORT-CULM MUTANTS The study of biochemical and physiological attribute parentf so theid san r mutant reveay s ma extene lth t of genetic divergence for various enzyme-mediated processes responsible for growth and development. Increased

235 activity of peroxidase isozymes in dwarf mutants of rice v;as reported [ 30 J. Specific quantitative and qualita- cive difference peroxida.sr sfo e isozymos were als- oob serve short-culn - di In . J 1 mIR-d 3 mutantan 8f K T f so vestigatio alphf n o betd aan a amylase activities, during early seedling growth on six induced dv/arfs, revealed marked quantitative differences f32j. Induced dwarf mutants were also found to differ .in their response to exogenous gibberllin (GA-z) /*33 J. In view of the suggestion that enzyme profiles may be usefu identifyinn li g dwarfing gene seedlint sa g stage /"21, 27 J experiments are being taken up on these aspects. t A preliminary study with six vorie- tie theid san r semi-dwarf mutants, revealed significant differences for various physiological and biochemical characters peroxidase Th . o isoeyme pattern amon- gin duced mutants compares ,a theio dt r parents, shov/ed marked differences in band number and intensity. Though most of the SD mutants showed reduced height, there was increase in fresh and dry weights of seedlings, alpha amylase activity and soluble protein content (Table VI). Generally, high yielding varieties are characterize early db y seedling vigour resulte Th . s obtained in the present study holds promise for selecting vigorous semi-dwarf segregatinn si g materialy ,b screening them for various physiological and biochemical parameters. Detailed investigations are in progress.

7. CONCLUSIONS Further intensive efforts should be made to induce siid recover alternative SD mutants in diverse genotypes -./ith specific characteristics. Evaluatio planf no t architecture, agronomic valu phenotypid ean c studies mamade yb availabln eo e nonalleli genesD cS . Also genetic, biochemical and physiological characterization mutantoD fS s is:essentia effectivn a r l fo planne d ean d usalternativf eo geneD eS ricn si e breeding.

8. RESEARCH PLAN FOR 1962-1987 Research Project: Semi-dwarf mutant Ricr - sfo eIm provemen Pacifice th Asi n td i aan . Certain promising semi-dwarfs, induced in Mahsuri, Basinat, 17 Ï-1TU i 370d ,an ïilakchandan1 14 T , YV , ,TK others, are included in the-project investigation. programme Th worf eo k involves: Inductio; a collectiod nan shorf no t statured mutants.

236 b) Classification and characterization of semi- dv/arf and dwarf mutants. c) Evaluation of these mutants for various morphometri yield can d attributes. d) Mode of inheritance of short stature and allelic relationships among induced and spontaneous SO genes. Penetrance) e , expressivity, pleiotropid can interactive effects of different SD genes. f ) Biochemical and physiological characterization of SD mutants. g) Hybridization and recovery of proraisins semi-dwarf derivatives and their agronomic evaluation.

REFERENCES

1 SEEXHARAMAN, R., Rice improvement in India, Current Science, J50 (1931) 517. 2 ATHWAL, D.S., Seini-dwarf ricwhead ean globan ti l food needs, Quart. Rev. Biol., 46 (1971) 1. 3 SEETHARAMAN. R. and SHOBHA RANI, N., High-yielding rice varieties in India, their impact and our chan- ging concepts, Indian J. Agric. Sei., 4g (1979) 141. 4 REDDY, G.M. and PADMA, A., Some induced dwarfing genes non-aileli Dee-Geo-Woo-Geo ct n gen ricn ei e variety Telj.akattera, Theor. Appl. Genet7 ,4 (1976: 115. 5 NARAI-IARI, P., JOSHUA, D.C. and RAO, M.S., Semi- dwarf rice mutant theid san r agronomic evaluation, Evaluatio Mutanf no t Stock Semi-dwarr sfo f Plant Type on Cross Breeding Materials in Careals, Vienna, Austria March6 ,2- , 1981. 6 PARTHASARATHY, N.P., Rice Breeding in Tropical Asia ut)to 1960, Rice breeding, IRRI, Los Banos, Philippines (1972T*5'.———— 7 SHASTRY, S.V.S., Towar ricda e revolution, Indian farming (August 1972). 8 MURTI-IY, V.V.S., Prospects and possibilities of utilizing induced mutation breeding programm deven ei - lopingLhigh yielding rice varieties, Proc. Symp. Role Inducef Th eo d Kutation Cron si p Improvement, Hyderabad, Sep. 10-13, 1979, D.A.E., Govt Indiaf .o , (1979) 1.

237 9 CHANDLER, R.F., Jr., Dwarf rice — a giant in tropical Asia, U.S.D.A. Year Book Agr. (19o8) 252. 10 AQUINO, R.C. and JEMNINGS, P.R., Inheritance and significanc dwarfisf eo Indicn a n mi a rice variety, Crop Sei. 6 (1966) 551. 11 ANONYMOUS Genw r shorMe ,efo t height, IRHI Reporter .2 (1973) 3. 12 SESHU, D.V., PRASAD SRINIVASAH, A U. RAO, , T.Ed .an SHASTRY, S.V.S. sourcew ,Me dwarfisf so e th n mi Assam Rice Collections, India Genet. nJ (19744 .3 ) 390. 13 ANONYMOUS, Source seraidwarfismf so , IRRI Annual Report (1970) 25. 14 BALAKRISUNA RAO, J., SRINIVASULU, K. and CHOUDHURY, D., Inheritance of dwarfing in crosses involving rice variety Baok, Current Sei. V[ (1972) 306. 15 CHANG, T.T., Manual on genetic conservation of rice (jermplasm for evaluation and utilization, IRRI Banoss ,Lo , Philippines (1976). 16 MIKAELSEN, K., Mutation breeding in rice, Innovative Approache Rico st e Breeding, IRRI (1980. )67 17 RAKIAH PARTHASARATHYd an . ,K , X-ra,N. y mutations in rice, Proc. 25th Indian Sei. Gong., Sec.IX, Abst (19382 .1 ) 212. 18 MOHANTY, H.K. and DAS, S.R., Breeding potential of induced plant height mutations in rice, Proc, Symp Role .Inducef Th eo d Mutation Cron si p Improve- ment, Hyderabad, Seo. 10-13i 1979, D.A.E., Govt. of India(1979) 55. 19 MISRA, R.N., Induced mutatio ricn ni e breedint ga Central Rice Research Institute. Cuttack, Proc. Symp Role .InduceTh f eo d Mutation Cron si p Improvement. Hyderabad, Sept. 10-13, 1979, D.A.E., Govt. of India (1979) 7. 20 CHAUDHARY, R.C., MANDA, J.S., MALIK, S.S. and SIKGH , Productiv,H. e mutant scenten si d ricf eo Uttar Pradesh, Proc. Symp. The Role of Induced Mutations in Crop Improvement, Hyderabad, Sept. 10-13, 1979, D.A.E., Govt Indif .o a (1979. )47 21 REDDY, G.M., Induced mutation ricn si e improvement— a decade of progress, Proc. Syinp. The Role of Induced Mutation Cron si p Improvement. Hyderabad, Sept.10-13, 1979, D.A.E., Govt. of India (1979) 15. 2 2 REDDY, G.M REDDYd .an .P.,T , Induced semi-dwarf Basuraati rice mutan commerciar tfo l use, Internat. Symp. Use of Isotopes and Radiations in Agricul- ture and Animal Husbandry Research,' New Delhi (Dec. 1971) 237.

238 23 REDDY, SomP, . e,T studie induction so mutationf o n s with physica chemicad lan l mutagen ricn si e (Ory_za jsativa L.)» Ph.D. thesis (1974) unpublished. 4 2 REDDY. T.P., REDDYPADMAd an . ,.A G.M., Short-culm mutations induce ricen di , India Genet. nJ 5 .3 (1975) 31. 25 SEETHARAMAN, R. and SRIVASTAVA, O.P., Inheritance of heigh othed tan r character rica n esi mutant, India Genet. nJ 0971L .% ) 237. 25 SINGH, V.P., SIDDIQ, E.A SV/AMINATHAd .an NM.S., , Mode of inheritance of dwarf stature and allelic relationships among various spontaneous and induced dwarf cultivatef so d rice Oryza sativ Theor, aL. . Appl. Genet. ^ (1979) 169". """ — *"~" 27 PADMA, A., Genetic and peroxidase isoenzyme studie somf so e induce othed dan r dwarf ricen si , Ph.D. thesis (1975) unpublished. 3 2 REDDYPADMAd an . ,A G.M ., Genetic behaviouf ro five induced dwarf mutants in an indica rice cultivar, Crop Sei (1977£ .T ) 860. 29 PADMA, A. and REDDY, G.M., Complementary inter- actio inducef no d extreme dwarf mutantn si 0. sativa L. , under publication (1982). 30. JOSHUA, D.C., RAO, N.S., BHATIA, C.R., MISTRY, K.B. and BITOBAL, E.M., Characteristics of dwarf mutants induce ricen di , Proc. Symp. Radiations and Radiomimetic Substances in Mutation Breeding, D.A.E., Govt. of India (1969) 185. 31. PADMA, A. and REDDY, G.M., Genetic and peroxidase isoenzyme studie certaif so n dwarfsativa. 0 n si , Genetics (Suppl.) 80 (1975) 62. 32 REDDY, T.V., SHEKAR, .B.P.S. and REDDY, G.M., Amylase activity in seedlings of certain induced dwarfs of rice, Proc. Symp. The Role of Induced Mutation Cron si p Improvement, Hyderabad, Sep. 10-13, 1979, D.A.E., Govt. of India (1979) 77. 33 UDAYACHANDRA, U.S., ANWAR, S.YREDDYd .an , G.M., Effec gibbef to r ellic aci certain do n induced dwarf extremd san e dwarf locan si l cultivarsf -o rice, Perspective Cytologn si Geneticy& s3 (1981) 597.

239 TABLE I. PARENTAGE AND SALIENT FEATURES OF SELECT SEMI-DWARF VARIETIES RELEASE INDIH DI A

Name/ Parentage Year of Mean Salient Designation release yield features (tons/ha)

IR 8 DGV/G x Feta 1966 5.0 LB Jaya T(N)1x T 141 1968 5.4 LT. Padma T 141X T(N)1 1968 3.0 SB Jagannath Mut. T 141 1969 4.5 :iS,LD,P3 Dala N 22 x T(N)1 1970 2.7 S3 Januna jf T(N)1xBas.370 71970 2.8 LS ,MD x Bas. 370 ICrishna GEB 24 xT(N)1 1970 3.0 i-1S,MSD,MRH Sabarmati /~T(N)1xBas.370 71970 2.9 MS, scented Bas,x 0 37 grain, MD, ÎIRb Ratna S TKM1R x 6 1970 4.0 LS Vijaya T90 x 1RS 1970 3.5 MS,MLD,R Lh,b,tv,blb Tellahamsa KR12xT(N)1 1971 4.3 LS,EM,CÏ Sona GEB24xT(N)l 1973 4.0 LS,MD,o mt Sb,Lh,tv Pusa 2-21 IR8xTKK6 1975 4.0 S3

Akashi IR8xN24 2 1977 4.0 SB IR36 IR1561//IR247 1981 5.0 LS O.nivara/ CR94-13 Rajendra U52xT(N)1 1976 3.9 LS,Eïl (105 days) Surekha IRSxSiam 29 1976 3.9 LS,MD Kiran 1976 3.7 SB, EM T90xIR[ 87 (100 days) i: 34 Kut. T65 1967 - E, HSB CR-4 Zinnia 31 x 1981 5.0 LS ,MD IRS-246 CSR-5 TKÎ^6xIR8 1979 4.9 LS,rlD

240 TABL (CONTD.. EI ) Name/ Parentage Yeaf ro Mean Salient Designation release yield features (tons/ha)

Vikram IRSxSiam 29 1974 4.6 LE,MD Supriya IRSx/" GEB24x 1973 4.1 "1C1 ^T^ T(N)1 7 Hybrid f Jhona 349 x 1972 4.8 LS.EH Mut. 95 T(H)17 (103 days) irradiated

Asha IR22 x W1263 1980 4M» LS,MD IGF1-37 Late Kalpi 248x 1900 5.0 LSjLD 1RS (1^5 days) B9 K7 /"T(N)1 x 1981 4.0 LS,HD NP 1307x Bas. 370 lon» B gL shorbold« B S t; mediubold= S M ;m slender; MD = medium duration; MSD = medium short duration; MRH s moderate resistance to Helminthosporium; MRb « moderately resistant to blast; MLD = medium late duration; R = resistant; Lh » leaf hopper; b = blast; tv = tungro virus; bi bacteriab» l leaf blight earl« M E y; maturing5 CT s cold tolerance; SB » stem borer; LD = long duration; PS s photosensitive.

241 TABL . CHARACTERISTICEII HR-4F S O TELLAKATTER D 7AN A SEMI-DWARF MUTANTS

Character HR-47 Tellal:attera Control Sd1 Control Sd4

Days to maturity 136.00 126.00 95.00 95.00 Plant height (cm) 141.90 114.80 130.40 90.60 No. of panicles/plant 18.50 28.20 11.20 14,50 Panicle weight (gm) 1.80 1.70 2.31 2.54 1000-grain weight (gm) 25.00 24.90 23.20 20.40 Grain, length (mm) 7.40 7.34 6.66 5.87 Grain bredth (mm) 2.13 2.02 2.40 2.24 Length/breadth ratio 3.47 3.63 2.77 2.62 Yield (tons/ha) 3.00 3.60 3.10 3.90

242 TA3LE III. F2 SEGREGATION IN CROSSES BETWEEN TK, Sd4 AND DGWG

Parents/ Total Mean Observed Rati valuP o e X 2 F < ? 1 F Plants height Frequency (cm) Tall Dwarf

TK 60 123.3 •M —— DGWG 150 94.7 - - Sd4 73 94.1

TK X DGWG F1 30 120.6 - « - TK x DGWG F2 702 - 529 1 3: 173 0.048 0.80-0.90 DGWx 1 4 GF Sd 26 116.3 - - ., DGWx 2 4 GF Sd 558 ' - 316 7 9: 242 0.953 0.50-0.70

Sd4 x ÏK F1 24 119.4 _ » — %. — Sd4 x IK F2 904 93.7 (Modal Class) - m c 0 11 TABLE IV. F2 SEGREGATION IN CROSSES BETVJEEH TK Di/ARFS AND DGWG

Parents/ Total Mean Observed Rati2 X o P value F1 & f 2 plants heißht frequency (cm) Tall Dwarf

dwar6 f- 58 73.95 - - — .. _

x JGW 6 1 d GF 20 121.28 am - .. - _. d.6 x DGWG F2 649 - 350 289 7 0.61: 9 0 0.50-0.70

«• dwarf-7 57 71.29 - - M* x DGW 7 I d GF 17 120.43 - - - - - DGWx 2 ? Gd F £ 760 436 324 7 ï 0.38 9 8 0.50-0.70 dv/arf-8 60 77.63

d8 x DGWG F1 27 118.56 - - ••» mm — d8 x ÛGWC F2 648 - 380 268 9:7 1.507 0.25-0.50 dwar9 f- 60 65.00 - - - - DGWx ? I d GF 15 121.38 - - - - d : 9DGV: 2 GF 577 - 327 250 7 0.02: 9 9 0.90-0.95 dwar0 f-1 60 56.27 - - - - Û10x rXKIG F1 20 124.26 - - .- - d10x DGV/G F2 471 - 249 222 9 : 7 2.063 0.10-0.20 TABL2 SEGREGATIOF . EV N CROSSEI N S BETWEE DWARFK NT S

Cross Total Observed Ratio X2 P value plants frequency Tall Dwarf

K T x 5 d 839 624 215 3 1 0.174 0.50-0.70 d7 x TK 750 564 194 «• 1 0.142 0.70-0.80 K T cl x G 682 520 162 «2 1 0.564 0.30-0.50 clS x TK 540 407 133 •z 1 0.039 0.80-0.90 d10x TK 652 497 155 «2 1 0.524 0,50-0.70 ci? x d6 812 451 361 O 7 0.165 0.50-0.70 6 d d Bx 792 453 339 g 7 0.289 0.50-0.70 d9 x d6 559 320 239 9 7 0.225 0.50-0.70 d10x d6 700 394 306 9 7 0.0004 0.98-0.99 dO x d7 623 346 282 9 7 0.340 0.50-0.70 ? d d9x 513 294 219 9 7 0.234 0.50-0.70 d10? d x 662 331 281 9 7 0.457 0.30-0.50 d108 d x 931 533 398 9 7 0.378 0.50-0.70 0 d1 d 9x 923 522 401 9 7 0.035 0.80-0.90

245 TABLE VI. PHYSIOLOGICAL AND BIOCHEMICAL ATTRIBUTES OF SHORT-CULM MUTAHTS AND THEIR PARENTS

Variety/ Seedling height Seedling Alpha amylase Soluble pro- mutant (7 days) (cm) weight (mg/ (mg maltose/ teins (mg/ml/ seedling) enzymef o l m ) seedling; Shoot Root Fresh Dry day3 s 5 days 3 days day5 s length length weight weight DGWG 2.27 6.75 25.93 3.02 39.60 75.9 2.65 3.90 Mah&uri 2.29 4.89 19.24 1.82 59.40 52.8 2.59 2.90 (Control) Mahsuri 1.87 4.49 13.83 1.60 57.80 39.6 1.90 2.40 (SD mutant)

hfl Basmati-370 2.71 4 • *TVJ 19.14 2.14 72.60 42.9 2.45 2.30 (Control) Basmati-370 2.69 4.91 20.28 2.23 67.65 42.9 1.50 2.30 (M 132-3-9) (Control1 14 T ) 4.61 5.95 22.92 2.60 67.65 56.1 1.80 2.50 mutanD S t 3.72 5.56 30.90 3.00 79.50 75.9 2.00 2.65 Tilalcchand&n 1.41 3.11 17.57 1.66 66.00 29.7 2.65 1.50 (Control) TCH 1 2.59 4.46 23.02 2.66 56.10 9.9 1.90 1.80 TCA-P2-5 2.97 4.97 19.20 2.76 39.60 16.5 5.20 1.65 YV (Control) 4.74 5.92 34.80 3.82 56.10 19.8 3.05 1.75 SD mutant 4.76 5.03 42.40 4.66 56.10 16.5 3.20 1.80 HR 5 (Control) 2.01 3.41 19.50 2.36 75.90 66.0 2.35 3.25 8 1 D S 2.01 3.64 17.52 2.19 72.60 75.9 1.00 3.20 STUDIES ON REDUCED HEIGHT MUTANTS IN RICE*

. NARAHARIP , S.G. BHAGWAT Biology and Agriculture Division, Bhabha Atomic Research Centre, Trombay, Bombay, India

Abstract

Two cross-bred derivatives of the mutan-t TR5 x TR17 and TR 21 continue o shot d w promis d weran e e advance wideo t d r scale testing. TR5 was found to carry a semidwarfing gene different from that in 1RS. New semidwarf mutants were screened from M_ through M, froo separattw m e radiation experiments e gibberelliTh . n response of seedling f mutano s d testean t r strain s evaluateswa d an d crosses of tester stocks and mutant semidwarfs were made for genetic analyses.

. 1 Progres Evaluation i s f Promisino n g Cultures.

At the First Research Co-ordination Meeting it was reported that TR-1 o lond TR-21tw 7an g e slende,th r grain promising derivatives from the cross of the mutant TR5 x 1RS were advanced to the pre-release minikit/district trials in three southern states, Andhra Pradesh, Karnatak Maharashtrd an a a [l]. Result f trialo s s conducte n 198i d 1 monsoon seaso e availablnar e a limiteonl o t y d extent froo statestw m Andhrn I . a Pradese th h per hectare yield average r sevefo s n district s 340wa s g 1k foR varietieT r s againsa s checks e th tr .339fo g 8TR-2k 1 gave higher yield in three of the five comparable districts. The trials are being continued in the current monsoon season. From Maharashtra State results were available fro 6 location4 m s spread over five districts. The overall average yield of TR-1 s 341wa 7 4 kg/h compares a 327o t d 1 kg/h RP-4-1f o a 4 check. In two districts where TR-17 are are planned to be conducted at 450 locations in the monsoon seasons of 1982 and 1983. TR-21 s continuei e Unifore testeb th o n t di d m Variety e Trialth f o s state. Two scented and fine grain cultures -VI-8 (a) and VI-95- originating frocrose th m s Basmathi-37 0Sonx a have been entered thi Maharashtre s th yea n i r a State Uniform Variety Trials. A total of 177 F, and F- progeny lines originating from five crosses involving IR-30, A-15, A-23 and Mahsuri (?) on one hand and TR-17 and TR-20 as male parents on the other were studied during monsoon season of 1981. This number has now been reduced, based on the yield of selected individual plants, to 65 and they are preliminarily being tested, with TR-17 as check, in a thrice replicated rod row trial.

Research supported under IAEA Research Contract No.2689/RB.

247 . 2 Inductio f Mutationo n r Reducefo s d Plant Height:

A tall growing photosensitive indica variety, White Luchai-112s ,wa e experimentsth use n i d . This variet vers i y y populae nortth n hi r eastern regio f Maharashtro n grais a it Stat nr fo qualitye . s shorIha t t fine grains wit a 1000-graih n weigh f abouo t 7 1 t grams. Dormant seeds having 13.5 90.047+ , moisture content were irradiated in a Gamma Cell-220 with 22.5 and 18.0 K rads and grown in 1978 and 1979 monsoon seasons, respectively. Abou e mont on d tseedling ol h s were planted singl a spacin t a y g e tim th f maturityo e t A . e graicm on , 5 n1 frox m c 5 o1 f each plant (A), five grains from every twentieth plan) (E t were sampled. Bul - populationM k s from these samples were grown. At various stages of crop growth, beginning from early tillering to maturity, repeated observations were mad maro e obviout e th k d an s suspected variant r planfo s t height. These plants were harvested individuall d growan y s progena n d theian y _ rlineM representativn i s e selections continue , generatioM n i d r ascertaininfo n g their breeding behaviou d studyinan r g their agro-botanical characters n 22.I . 5 K rads gamma-ray treatment, 18000 seeds were use againss a d t 3000 control seeds. In M. generation, seedlings showed nearly 30% height reductio t theibu n r surviva t transplantina l s similawa g r controle tth o , around 66%. However, becaus f varyino e g degreef o s sterility in treated plants, only 817» of the planted population could be sampled for fertile grains. M2 seeds in all the three methods of grain sampling totalled only 24138. Moreover, when grown in M« , death of seedlings due to iron chlorosis in the nursery bed, and subsequent gaps in the transplanted field reduced their number by 467., to only 12979. From among these a total of 315 variant types" were isolate f theseo 9 d whic24 an ,d h germinated well could be studied in M-. Among 182 established mutant lines 202 selections were made and further studied in the M, generation during the 1981 monsoon season. f 1500A secono t 0lo d seed s agaiwa s n treated n 197i 9 K radswit 8 . seedlin1 M h. g surviva t transplantina l s gwa 88.37o. Gaps in the transplanted field reduced this number to 11815 of which 11540 bore fertile grains. The seed numbers sown and germinated in M- were 34439 and 30515 respectively in treated lot as against 7740 and 6703 respectively in control. In control ear emergence was completed between 122 to 129 days and the plant height f theo m% bein90 , range. gcm cm ove8 0 d18 15 r betwee o t 7 12 n Variants selected in M_ numbered 522 of which only 345 had fertile e 198s seedgrowth wa 1harvestt n a si - n M monsoo e Th . n season. For all the mutants generated in both the above experiments information with regar r emergence ea o dayt do t s , plant height, panicle length, numbe f effectivo r e tiller s recordewa s 0 2 d plant r progenype s . Individual plant selection d alsan so 20-35 plants per line were harvested for determining grain yields. Count r determininfo s g spikelet fertility weree taketh n o n longest panicle selecteth f o e d plant e 100-graiTh . n weights also were recorded. Mea ne character valueth r fo s s studied have been computee undear d r an dtabulatio r detailefo n d scrutinyn I . the current monsoon season, a total of 98 mutants and selections, as grouped in table 1 are now in preliminary tests for yield in three replicate rod-row trials. Besides, 374 mutant lines in different height ranges (see table 2) are being grown for further confirmaton and accessory studies. The mutants also include lines less than a week early, weak, sterile type d chlorophylsan l deficient

248 mutants such as chlorina, zebra, fine striped, red patched and brown pearly dotted etc. Thirty -five of the mutant lines were received froe Paddth m y Research Unit, Sindewahi, where e th par f o t - seeM s senwa d t _ generationearlieM e r studyth fo tw n I fe . a , lines showed normal-looking plants of the White Luchai-112 parental type. Several such plants were retained on the assumption that their occurrenc o naturat . e hybridF du ls a es crossin wa s g in the previous generation. Mutant lines in which such natural crosses occurrred were mostl f distinco y t types like Dwarf Bunchy with 60-70 cm height and more than 100 tillers and Short Bunchy with 100-11 m heigh5c d 40-6an t 0 tillers. Their breeding behaviour was studied in F» and F_ generations in monsoon season of 198 d rab1an i seaso f 1981-8o n 2 respectively. Phenotypi2 F c d genotypian _ segregatioF c n indicated mono-genie recessive inheritance of the mutant phenotypes (table 3). Several such natural crosse e agaiar s n being studiee currenth n i dt season.

. 3 Gibberellin Respons Ricen i e ;

A rapid seedling tesr Gibberellifo t n respons n rici e e has been described by Narahari and Bhagwat [2]. The A responsG s sincha e e been studiemutant7 13 n f Whiti do s e Luchai-11 0 referenc3 d 2an e stock f dwarfs/semi-dwarfo s s d talan l parents e datTh .a analyse r permitfa e followino s dth s g observations: ) 1 Significantly strong correlations were observed between leaf sheath length and seedling height both i-n water-treated controls and GA_ treatments.

s compareA ) 2 Whito t d e Luchai-112 _ stimulatioGA e th , n indice referencn i s e stocks varied betwee 4 (Siya3 n m Kuning Mutant 233d )an % (IR-30leae th f r sheat)fo h and between 49 (Tainan-5) and 174%(I-gee-tze) for seedling height (table 4).

3) The indices for both leaf sheath length and seedling height of the dwarf introductions were generally lower than that of White-Luchai-112. The induced mutants showed a range between 64 ( f E-16) and 146% (ÏA-8-1) r leafo f sheath lengt d betweean h 5 (CA-6-96 n d 136)an %. (Chlorina-1) for seedling height.

4) Correlated responses in leaf sheath length and seedling height varied among dwarf introductions. The same phenomenon s observewa d amorg induced mutants. However e latte,th r coul e tentativelb d y identifie s belongina d 5 4- o t g groups indicating possible similarities with the dwarf introductions in the respective groups.

. 4 Studie Referencn o s e Stock Dwarff so Parentsd san ;

Agro-botanical information was collected on dwarf and parental reference stocks in the monsoon season of 1981 and the second rabi seaso 1981-8f no 2 respectively . (Table6) & s5

249 s compareA e monsooth o t dn season e stockth , s showe n rabi d i season a genera, l increas e numbe th r emergenc f ea dayn o ri eo t s e (exception being TR-5), productive tiller d graian s n yield (exceptions being White-Luchai-11 d Siyaan 2 m Halus Mutant t the)bu y exhibited reduced spikelet sterility. Their height in general was also reduced maximue th , m reductions being42-4 n Intai m n3c Mutant and White Luchai-112.

5. Crosses with Dwarfs:

In order to understand the allelic relationships among different dwarf types, and also to isolate early desirable dwarfs, the following crosses were made in the rabi season of 1981-82.

S.No. Cross Particulars No. of F, plants

1. Dee-geo-woo-gen x TR-5 6

2. I-geo-tze x TR-5 9

3. K 8 x TR-5 1

4. Chlorina-1 x TR-5 6

5. TR 5 x Cheng-chu-ai-11 5

6. f A-42-32 x TR-17 3 w bein. plantF no e e g Th ar s studie currene th n i dt season.

REFERENCES :

[1] NARAHARI, P., Joshua, D.C. and RAO, N.S.; "Semi-dwarf rice mutants and their agronomic evaluation", presented at the FAO/IAEA First Research Co-ordination Meeting on Evaluation of Mutant Stocks for Semi-Dwarf Plant Type on Cross Breeding Material Cerealsn i s , Vienna, Austria 6 March,2- , 1981.

[2] NARAHARI, P. and BHAGWAT, S.G., "A Rapid Seedling Test for Gibberellin response in Rice". Curr. Sei. (In press).

250 T1BLB 1 OP EAELY PLOWERIHG WJTABTS OP WHITE LUCHAI-112

Group Partievlars ,? of l»werin J-Q** A . r$M "^^ - *•• CultaroB («m) Mutants Checks* Total I Early dwarfd an s semi-dwarfs— 1 -C95 upto 110 11 2+2* 15 n. Early se.ai-4warfs-2 <95 111-120 10 2+2* 14

HI Mid-late dwarfd an s 96-110 upto 110 14 2+1* 17 ' semi-dwarf a-2 0 12 ft i? Early semi-talla <95 121-140 15 2+1* 18 1 T Mid-laie semi tails 96-110 121-140 19 2+1* 22 TI Early tails <95 141-150 12 2+1* 15 TU Mid-late tails 96-110 141 17 2+1* 20

Total 98 14+9 121

Include* s «heck Whits- e Luehai-11 Locad 2an l Early Luohai- which are grown separately for comparisons.

2 PHEQUEHCY OP KDTAHTS IK DIPPEREST HEIGHT SAHGES Height Ho. of f o . Heighlo t range mutants range mutante (on) (en) Dwarfs ft Semi-dwarfs Semi-tail t Tailsf s 50-60 4 3 121-135 0 61-70 6 131-140 79 71-80 22 141-150 56 81-90 25 7 151-161 0 91-100 22 161-170 11 100-ltO 37 >171 6 111-120 36 Total 222 Tetal 152 Grand Tota4 37 l 251 TABL3 E

Segregation Studies in F2 and F_ Generations of Suspected aaiUlBJL \S4UOOCB UUBÇXVCU Ail ****T XU w ^J^JiU H wO v0 UA y — * a ^r treated White-Luchai-1 12

p Sin ', F Mutant Population Families fe ^ No • No. Type Total Tlon- Muta2 - Total Hon. Segre2 - \ 1 « Mutan/ t n t aegr- gating,?'^ type typ* v e egat« vu«; ing 1 2 3 4 567 8 9 10 11

1. Y A-50-19 Dwarf - Bunch - y 13 8- 1 0.4733 107 5 2. 1 A- 70- 17 n n 138 116 32 6.0387* 30 11 19 0.1500 3. f A-68-6 n n 148 106 42 0.9009 30 7 23 1.3500 4. Y D-94-9 n n 144 111 33 3.0000 «, _> . «, 5. Y G-2-7 II II - 13 - 8 9 1.169102 9- 1 6. Y G-4-11 n n 138 0 12 18.12568 * - - <» - 7. Y A-67-35 Short Bunchy 138 6 2 12.79212 3 30 11 19 0.1500 8. * B-60-26 n n 146 112 24*+!$ Sownn .i the first erop season of 1982. 9. VB-65-9 n n 138 112 26 2.7923 10. Y A-18-12 Semi dwarf 140 107 33 0.1524 30« 11 19 0.1500 11. y A-19-1 n n 144 106 38 0.1481 12. A-19-24 n H 139 105 34 0.0216 31° 13 18 1.0350 13. y A- 19-2 5 n ' N 138 116 22 6.0387* - «. «» 14. r A-36-1 1 ii n 138 113 25 3.4879 31 9 22 0.2568 15. Y A-82-4 Thin Culm? 138 111 27 2.1739 30 10 20 0.000 drooping leaves 16. Y D-58-12 Thin culm; 126 97 29 0.2645 30 8 22 0.6000 young leaves light green 17. YD-77-17 Compact pani- 140 113 27 2.4381 30 9 21 0.1500 cle 18i rB-21-12 Semi-tall, weak 138 117 21 7.0436* -, _ . 19. Y E-24-24 Thin culm; 138 105 33 0.0869 29 11 18 0.2744 narrow leaf 20. rB-28-18 n n n 141 9 3 100.5312 9 31 9 22 0.2566 21. Y CA-4-U Semi-tall .lees Individual mutants .... tillering e eafcilb coul t yno d 22. y D-85-3 Semi-dwarf - • distinguishe - r o d 23. y D-87-5 brown pearly » dot< s studie n detaii d l 24. Y D-90-17 Semi-tall; slifcutly at different » « » . drooping leaves growth stages, although initial studies indicated monogenlc se gre- ' • gan tio

Pleas e nexse e t pag r Foot-notesfo e .

252 Foot-note r Tablfo a a * deviating significantly from-Jt1 ratio (probability ^.0.05) a • Short Bunchy type narro= « b w leaf type • In Fp generation the stai-dwarf mit an t a with erect leaves showe a heighd t rang f 60-11«erd o e an e n 0o clearl y identifiabl observatione ey y b e e heighth » f non-mutanto t a ranged between 106 and 170 cm. Classification of F lines was somewhat arbitrar s segregerioya cleao s t t ou r no s nwa becaus f vero e y shor) 0 OB«4 cm t vero )0 t 15 y tal> ( l heigh f planto t a which alto showed segregatior nfo . flowering' duration. N.B. Mutants designate originateA ^ s a d d from individual plants while others are of different bulk origins.

253 TABLE 4 CORRELATE - STIÏOJLATIODGA N INDICE P SEEDLINO S G HEIGHT ADD LEAP SHEATH LENGTH IN DWARP REFERENCE STOCKS*

. No . 3 Culture Seedling Leaf S.No. Culture Seedling Leaf height sheath height sheath index index index index (x) (y) U) (y)

1. Tainan-5 48.61 75.81 17. Cul. 25315 125.92 189.32 2. Oorpandy 57.67 59.98 18. Oui. 25316 126.45 191.57 3. Siyam K. Mutant 59.87 33.87 19. 'MN-54-42 130.26 184.01 4. Nodula Dwarf 72.50 70.05 20. K-8 133.03 136.33 5. D-66 (C-I-11033) 76.23 111.34 21. 2533. Cul 7 133.11 145.89 ; N> 6. D-24 78.07 123.31 22. Cul. 25336 133.73 163.04 7. TR-5 79.03 76.08 23. Intan Parenjt 134.14 107.52 8. Delta 88.31 136.87 24. Cul. 25372 138.51 210.93 9. D-66 (IRRI) 90.07 131.17 25. DGWG 138.70 179.95 10. Siya Paren. mH t 99.12 97.30 26. D-6-2-2 139.94 186.56 11. TR-26 99.81 93.69 27. Cheng Chuai-11 140.37 194.36 12. White Luohai-112 100.00 100.00 28. Cul. 23332-2 146.10 216.63 13. Siyam K. Parent 100.21 123.03 29. Jaya 150.63 228.82 14. M-101 106.70 184.95 30. IR-30 157.85 232.80 15. Siyam H. Mutant 116.16 136.24 31. Intan Mutant 162.28 212.07 16. Chlorina-1 124.22 136.17 32. I-Geo-Tze 173.94 215.41

0.87*r« * 17.6977*1.441* Tt 4x Seria* l arrange ordee th increasin f rn o d I g respons seedlinn ei g height, S >a<~* CM O O «* KN r» o CO ifXpg S l bf CW D o ^ Cf — I O 0 C0 M W ^ f vO cfl t*^ CM (^ '^ f*^ ^* ^«O K*S Jj\ 0 ~ CM

*• a \ J5 iU 4» S M O W O ä •d-7 H o fa •a o f» 0 vO t*** m if\ t«» cn vo ^ a v ca en >-* h 4* «-«-»-»M C ^ \ K > K - t— »^ £ W O U) 4-» W v VI P H r-Uä »— in M W 0+"3 00 in cMO«~in^-* ^ US 00 ca S 0 •H0 * o^ -» «~ öt* m ^ o v (40™ r* 0 • ** CO CM CD W ^ •" »-CMCMCMCMC^ M o o e CM 3 H 0 o CM a ^l- o o " 8 1 4» •««• CD O U «D •H ca T» 4"~» 5 vOt-K>CM COvO t-"* &4 K .-* . O (4 ^B ^O t- 1 «j ca 1 m^cMtMeTvocoJJ 1. M t Ü'**i^Bf^ PQ ^4 ca 1 ^"f ca Pi P» i-l 4» *~ Vl M . O P ca H -5 CD ca W CD O • C » 4-» o J3 4» O CD •o ca w a M i K 04 M tï vo 4-» r- J3 r-inK>CMKlCOCMlfv •H W 0 *c «- W ^>3 r^ a^-f H S (O 4* 4» •H -H>-x Vl W • Cn C 0 04 4* 4* Q t^ a pq T- M O O M IV V Vl VI •• •• »4» CD Hft 4* qy rf^% o CD O •H «t'a W § ^ ^ O ^* O \ ^ C O ^ a3 M c ^ o»^ ^ ^ in O * CM 0 1 •H CD «|X-> » a ~^-CMCMCMCMCMCM - T * s 4» § J V* H «U CD a a o CO Q o CO CD T- M o w p 00 a 0 H* ca ca * •o VI ' a« (4 •g VO W ^ o n e o o ~ c § ^ D C o c B K> "* ä~ CM •*

a ,iS ^•nvoe-ajoi-^cni-vo^vo >» o ^ « a 1 g 9a *»a K\ O ^r-KNv-t^tÔtnvO UA CM *-Ô R w a» du ca {•^ t*» f^ C** t*" ^ O^ O"^ O^ T** O^ O^ CO Vl X ^* *" o to «1I |M l4 W o a1 4* CO «i 1\ p t! T 7 h C1 O HH M9 ^^ Ô* CM 3 T4 ^^ |t 1 |O t^\ ^™ CM t^ \ K * •< \ K 4 *> 4K -• \ K v!O •O d >4 CM 3 a 'GO t- CO VO CM CM CM ** CM ö up4 CM ^ vo o 4» in CM i i imfKN

M Q 4 » « &4MOOoSc3M

H C1 cas». - »•••*•«-

255 1 2 3 4 5 6 7 8 9 10 11 12

14. Cul -23372 91.1 100.7 26.5 14.2 25.7 28.3 270 62 23.0 30.0 15. Cul-25315 112.3 101.8 29.5 10.2 28.0 31.5 230 75 32.6 27.0 16. I.R.28 80.6 102.1 26.3 10.4 21.4 27.2 125 9 7.2 29.9 17. IB-22 109.9 102.5 26.1 12.5 26.9 29.5 117 14 11.9 32.0 18. IB-20 107.2 107.1 30.1 11.3 . 25.1 32.1 189 20 10.6 23.0 19. Siyam Kuning 146.3 122.2 25.1 15.1 17.2 27.2 174 10 5.7 32.0 Mutant 20. Intan Mutant 93.6 133.0 31.7 13.1 27.8 35.3 211 17 8.1 42.4 21. White Luchai-112 110.0 140.7 19.6 16.4 53.0 19.0 300 13 4.3 52.0 22. Siyam Kuning 144.3 147.7 23.6 16.0 16.1 24.0 165 12 7.3 24.0 Parent Siyam Halue Parent 144.6 148.2 26.9 11.9 23.2 26.5 214 25 11.7 36.0 »o 24. Intan Parent 119.8 150.8 30.2 12.3 32.4 29.8 309 73 23.6 34.0 25. Oorpandy 144.3 162.9 27.9 16.4 34.1 27.4 155 25 16.1 39.0 26. Siyam Halua Mitant 92.5 164.9 30.3 13.6 37.6 32.3 129 19 14.7 41.8 (ii) Date of sowin. 27 g 7.81 i Date of treneplanting: 18.8.81 (Plot No. U-1) 1. Tainan-5 87.7 56.2 20.2 9.1 13.0 22.2 . 143 23 16.1 20.0 2. Nadula dwarf 107.4 65.2 16.2 6.1 20.9 15.6 168 16 9.5 37.0 3. vD-66 (IHfi-I) 68.7 65.2 17.7 7.9 5.3 18.0 60 5 8.3 9.0 4. Cheng chu-ai-11 81.6 78.6 23.5 9.8 17.8 24.0 198 7 3.5 34.0 5. I-geo-tze 93.3 79.9 21.4 11.9 17.8 23.0 152 6 3.9 33.0 6. IB-30 83.1. 86.0 23.4 11.5 16.6 24.6 2 9 3 17 15.0 32.0 7. De e -ge o-woo-gm 91.8 87.0 24.0 10.2 18.8 - 160 9 5.6 15.0 6. K-8 109.7 117.0 27.7 13.3 32.6 26.5 194 41 21.1 35.0

•Serial arrangement in the order of increasing plant height. TABLS 6 Performanc f Semi-dwaro e d Parentaan f l Reference Stocks0 Locatio t nBARC ,5 Bomba08 0 40 y Season : 1981-82 Rabi (second crop) Spacin : Integ r t«in-ro« c Inter-ro0 m4 & : a Inte. w& cm r 0 hil2 : l Date f eoningo s : 16.12.198s 23.12.198114 * Dat f transplantingo e : 20.1.1982 (Plat U-11)

SI. No, Culture particulars Character Keans Selected Individual Plant Days to Plant Panicle Produc- yield Pani- Spiklet6/panicle Grain Heigh- em r t ea length tive per «1« Total Sterile Sterility yield ergence (cm)' (cm) tillers plant l*ng- (Hos.) (Hos.) (y;\ (gm) (Noa) (gm) th <, 1 2 3 4 5 6 7 8 9 10 11 12 K) 1. D-24* 87.9 77.2 18.8 13.3 19.6 ^ 146 7 4.8 25.0 2. D-66*(C-I-11033) 90.5 76.7 19.4 17.4 23.4 .. 108 5 4.6 32.4 3. M-101* 87.7 75.9 20.8 13.1 26.5 _ 77 6 7.8 31.0 4. Delta* 90.6 84.1 20.9 10.7 20.2 - 95 18 18.9 32.0 5. TR-5 100.6 66.3 16.8 20.2 33.4 . 176 7 4.0 38.0 6. Cul. 25336 113.2 72.1 22.6 25.4 35.7 _ 107 5 4.7 44.5 7. Cul. 25337 113.3 74.8 23.4 22.0 40.6 - 135 2 1.5 63.9 8. Cul. 25316* 123.7 79.7 23.8 24.7 57.1 M» 118 2 1.7 85.9 9. KN-54-22 105.3 67.6 20.8 16.7 33.4 __ 201 9 4.5 45.4 10. Cul. 2332-2 105.5 68.3 21.0 19.4 44.0 —— 212 13 6.1 59.5 11. IR-30» 95.8 72.1 22.8 21.3 31.8 - 161 8 5.0 36.7 12. Cul. 23372 103.5 68.7 21.2 17.4 39.2 - 175 5 2.9 62.7 13. Oui. 25315 113.0 79.2 25.4 23.5 43.8 ~ 133 15 11.3 62.0 14. Siyam Kuning Mutant - 141.5® - 25.1° - —— - - • - 15. Intan laut tan 109.1 9C.2 25.9 20.0 40.2 __ 153 6 3.9 33.0 16. tfhite Luchai-112 106.8 98.7 16.7 37.8 34.9 —— 154 11 7.1 41.2 * N . N 17. 105.8 96.1 17,4 31.9 37.3 __ 136 9 6.6 30.5

18. Siyam Kuning Parent - 137.9® - 24.60 ------

19. Siyam Halus Parent - 144.5*- - 20.20 - - - - — — P.T.O. TABLS 6 (cont,)

1 2 3 4 5 6 7 8 9 10 11 12 . . . 20. Intan Parent 143.3 146.1 29.9 23.9 4 21. Oorpandy - 162.6® 24.2© — — - - — - 22. Siyam Halus mutant 105.6 127.8 27.3 15.1 29.1 - 156 19 12.2 34.1 23. Tainan-5 (73-76)* 12J.2 74.8 22.8 15.5 32.- 3 196 18 9.2 48.2 24. Hadula dwarf - 76.1© — • 20.3® - - — - - — 25. D-66 (1ER) 91.2 78.1 19.8 16.4 23.8 - 108 5 4.6 28.9 26. Cheng-Chu-ni-11 100.9 78.9 22.3 19.0 41.6 - 160 5 3.1- 46.4 N) I. Geo-Tze 109.5 77.4 21.2 23.6 42.2 - 130 5 3.8 59.2 W» 27. 00 28. IR-30 101.6 66.1 22.1 19.8 25.- 1 128 7 5.5 25.0 29. o-woo-gee B-g ee n 114.8 84.2 23.9 20.5 45.- 6 171 9 5.3 56.7 30. E-8 123.6 109.6 26.7 32.0 49.7 - 153 49 32.0 65.6 31. TH-26 » 138.4© . ,23.0® — _ - _ — -. 32. Jaya 115.0 72.1 22.1 19.8 24.- 0 156 16 10.3 41.0

* Serial arrangement mostl conformitn i y y wit earliee hth r report ThesO e culture t shoemergencr no wea d sdi e til endy lMa . Hence heighs wa t recorded upto tip'o tillerl fal lead san f counted. A RAPID SEEDLING TEST FOR GIBBERELLIN RESPONSE IN RICE*

P. NARAHARI, S.G. BHAGWAT Biology and Agriculture Division, Bhabha Atomic Research Centre, Trombay, Bombay, India

Abstract only

Seeds were placed lemma side dowd sequentiallyan n , with their glum e sam th ende n i sdirectio wetten i n d folded filter—paper. n holesm aparPi m 0 1 ,t were providee filter e foldth th f o st -a d pape o facilitatt r e root penetration e papeth rd an ,"sandwich " units were placed in plastic sacks. The sacks were kept in trays containing GA_ or distilled water. Continuous immersion of the paper s ensureswa y periodicallb d y replenishin e solutionth g s up to a 2.5 cm height. Seedlings were grown in a growth chamber at 30+_ 1C in continuous light of 1500 lux. After eight days control seedlings showed full second leaf developmen d measurementan t s were s fountakenwa t dI .tha t relative e seconseedlinth f o d p leags to height wa fe th o t , a better measure of response (lower C.V.) than the relative first leaf sheath lengt t thabu ht either measur s suitablewa e e Th . sensitive varieties responded to all concentrations tested from 10~o 10~t 7 4.

Comment adde C.Fy b d . Konzak. Because the growth was essentially twice that of the control f thao te us concentratio , 0 a1 t n only along wit watea h r control may serve as a measure of responsiveness. The index can thus be controe calculateth f o l % response s a d . Also becaus normae th e l GA syntheses processes is turned off in light, it might be preferabl o gro t e seedling th w n totai s l darknese firsth tr fo s 4 day 3- o allot s w maximal developmen e firsth tf o tlea f sheath, then place in light until measurements are taken.

* Research supported by IAEA under Research Control No. 2689/RB. Full manuscript accepted for publication in Current Science.

259 EFFECTIVENESS OF BREEDING SHORT-STATURE RICE CULTIVAR MUTATIOY SB N INDUCTIO . HYBRIDIZATIONvs N

C.H. HU, N.F. Davis Drie rElevator& , Inc., Firebaugh, California, United States of America

Short Communication

s beeIha t n argued tha n developini t w ricne ea g cultivar, mutation breeding has not been as effective as conventional cross breeding. This e trueb t ,no dependin y e breedinma th r o n o gy gma objectiv d whaan et kinf o d germplasm is available in the breeding program. All the short-g'rain and medium-grain cultivars in California rice are Japonica types genetically closely related. An induced mutation short-statured cultivar, Calrose 76 officially named and released in 1976, started the tall rice improvement. The following table show 1 short-stature1 s d rice cultivars developed since th e release of Calrose 76, six of them using Calrose 76 as cross parent, three of them derived from mutation induction directly d developmenan , t needed fivo t e seven years e resTh .t were develope y conventionab d l cross breeding usin8 1R g as short-stature source and required 9-10 years.

The semi-dwarf gene Dee-geo-woo-gen was the short stature source of Indica rice, TN1 and 1RS. These two cultivars were widely used in the world r improvemenfo f talo t l lodging rice. Short-statured recombinants wert no e difficul o fint t d among progenie f short-talo s l rice crosses. However, when short-stature Indica rice is crossed with tall Japonica rice, hybrid-sterility occurs e selecteTh . d recombinants were usually also associated with some other undesirable characteristics such as susceptibility to low temperatures. e graiTh n shap d cookean e d rice quality were alst acceptablno o n somi e e rice- consuming countries presene th n I t. rice breeding progras wele U.Sa th .l n i m n Asiai s a , locally-developed short-statured material e increasinglar s y used. Successful breeding of short stature rice varieties is not confined to short plant heigh d higan t h yields o includt t alss ,bu ha oe adaptability and good grain quality e particulaTh . r meri f mutatioo t n breedin s thai g t it does not destruct an established genotype, but may quickly replace it by a better "isogenic" type. The results of rice breeding in California during the last decade provide a good example.

261 Short-stature rice varieties in California bred by mutation induction and hybridization

Parent New Method Variety(ies) Duration Variety Remark

Mutation breeding Source 60, Direct Calrose Co 1969-1976 Calrose 76 First short-stature variety in USA 60 Terso Co 1975-1981 40 - lat M 1e maturing Kokuhoroso C e 1978-1982 Rice Researchers, Inc. (personal information)

Indirect Calrose 76/CS-M3 1973-1977 M 7 late maturing CS-M3/Calrose 76// D31 1974-1971 10 M 9 very early maturing Calrose 76/ CS-M3//S6 1974-1980 S 201 early maturing Calros/ 76 e NFD-4-2-1-1 1976-1981 Calpearl very early maturing D51//S6/ Calmochi-201 -1981 Calmochi-202 glutinous, early maturing Calrose 76/ 1974-1981 30 M 0 CS-M3//M5 1974-1981 M 302 intermediate maturing

Conventional breeding

IR 8/CS,-M3 10-72 1968-1977 M 9 early maturing Terso/3/I/ R8 CS-M3//Kokuhorose 1973-1981 20 2M early maturing

underlined = Earl r short-staturo y e induced mutant f Calroseo s , D51 was considered to be similar to Calrose 76. Calmochi 201 is an induced glutinous mutant of 86, released as variet 1979n i y .

262 LIST SEMI-DWARF SO F CEREAL STOCKS

The lists are prepared in relation to the Co-ordinated Research Programme.

e firsAth t t Research Co-ordination Meetin n evaluatioo g f cereao n l semi-dwarf mutant r crosfo s s breeding, March 1981, programme participants were requested to list semi-dwarf mutants available at their institutes including also non-induced semi-dwarf stocks being used in cross-breeding programm r shorfo e t stature. List- prepares i I d from such lists provided by programme participants.

Furthe s requestewa t i r o namt d e breeder d institutean s s provide characteristics of the listed semi-dwarf stocks. List-11 gives that information.

List-Ie Ith n :

Parents of semi-dwarf stocks derived from cross breeding, are show bracketsn i n .

In column "Culm length", figures are in cm and those of parent cultivars are shown in brackets.

263 LIST I

List of semi-dwarf cereal stocls

fîutant t-arent Mutagen Culm Gen ) e(s Remarl-abl e Breeder '.s,

A\ oria saliv) . (L a

(Reported by /2 1

Aurora 6 Short Short straw, 4O-5O emal1 grain, nice panicle

tïgdolo3 2 n Source of short culm /20/

Elgdolon 26 /2O /

MaupO 7 a Source of short culm n mo r a H D 4 O13 T Nf 45-50 1 dam. Short straw,panicle - GO 1 ( iculty,shorf f di t 125) peduncle

PA 7773-551 Short straw,normal grain and peduncle

HcrrleufTi vulgär) (L e

D 240 Proctor Sodiu0 3 m 1 rec. /51/ e id z a

D 311 99 " nutans, low yield /51/

D 321 6O 2(7) rec. " " /51/

D 341 87 1 rec. nutans, yield as /51/ parent variety, poor lodging resistance

264 D390 recl . erec 9 7 t Did, yield /5l/ s parena t variety, good lodging resistance

D 415 rec1 . erectoid,lo 2 5 w yield, /51/

D 519 recl . semi—prostrate,yiel 4 7 d /5l/ as parent variety, poor lodging resistance

D 537 rec1 . erectoid,yiel 6 7 s a d /51/ parent variety,poor lodging resistance

D 545 69 Irec. erectoid,yield as /51/ parent variety,good lodging resistance

D 640 52 Irec. erectoid w yiel,lo d /51/

" " D 1282 75 1 rec. semi-prostrate, yield /51/ s parena t variety, poor lodging resistance

D 147O 82 2C~)> nutans, low yield, /51/ rec.

D 1674 82 1 part, nutans, yield as /51/ rec. parent variety, poor lodging resistance

D 371O 77 1 rec. erectoidjlow yield /51/

D 1819 73 1 part, habit ' Bamboo ' type, /51/ w yiello recd .

(Reporte y B.Giorgib d ) /52/

Riso 9265 Bonn gamma 75 Rht / I/ rays (1O5)

(Reported by S.E.Ullrich) /45/

Winter habit Boyer <6-row) Luther 89 lodging resistant, /33/ (109) wide adaptation feed type

Hesk 107 ti n /22/ (6-row) (1O9)

265 Luther Alpine DES 109 lodging resistant /33/ (6 row) (118) feed type

Mal Luther 107 lodging resistant /22/ (6-rowO) (109) narrow adaptation feed type

WA 29O5- Jotun,Luther radiation 77 lodging resistant /33,45/ S DE (9B-75(6-row)> semi—prostrate, feed type

Spring habit Advance Triple Bearded 89 lodging resistant, /33,45/ t (6—rowlo r Ma ) (99) malting quality

Advance Advance Sodium 55 lodging resistand, /33,45/ Dwar f azide (89) 1 rec. some sterility (6—row)

Gus CCXXXII 84 adopte o irrigationt d , /59/ (6—row) (Jotun) (123) lodging resistant, Barley Yellow Dwarf Virus resistant, feed type

Kombar Jotun radiatio7 8 n adapte o irrigatiot d n /27/ (6—row) (98) lodging resistant feed type Kombyne Jotun radiation 67 /27/ (6—row) (98)

Poco 4O extremely short and /35/ (80) early ,t stifstrano s fi w WA 8517-74 (Pirol ine DES & 71 lodging resistant, /33/ (6-row) x Valticky) X-rays (99) malting quality

WA6 7 10365-79 CCXXXII lodging resistant /33,45/ (6-row) (Jotun) (123) feed type

WA 10698-76 Valticky X-ray1 7 s lodging resistant /33,45/ (2 row) (91) good malting quality

WA 11005-81 WA 9037 Sodium 70 /45/ (2 row) azide (79)

WA 11O48-B1 WA 9044 " 64 /45/ (2 row) (72)

WA 11081-B1 Adwance " SO some sterility 745 / (6-row) (64)

266 WA 110S4-B1 52 /45/ (6—row) (62)

WA 11094-81 More:- 62 /4S/ (6—row) (79)

Orysa sativa (L.) x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x >x :x x x x x x :•xx x :x (Reported by M.A.Awan) /5B/ DM-2 Basmat 7 O 13 gamm37 i y ra a short stature, / 2/ 177 lodging resistant % yiel30 d advantage DM-16-5- " l4 14 gamm y ra a short stature,lodging (177) resistant, 20V. yield advantage DM-107- " 1 4 10 gamm y ra a non- short stature, / 2/ (177) allelic lodging resistant to DGWG 407. yield advantage

(Reporte y P.Naraharib d ) /32/

C.A.M. Central 1 8 non-allelic /41/ African to DGWG var iety

Jagannath T 141 1 1O x-ranony -e weeOn k later than T141/28/ allelic to DGWG

Semi-dwarf HR-47 DES 9O retains grain charac- /37/ Basmati teristics of HR-47, earlier by 10 days, yields 15-2O 7. more

TCA-P2-5 TilakchandaS EM n 40cm 25 days earlier and /12/ shorter higher yielding than than parent parent TR-5 SR-26B 61 non- cigar shaped panicle, /36/ allelic very stiff straw to DGWG

267 TR-28 Basmati-37O DES 96 retains grain qualities /Z2/ (B-63) including arom f pareno a t var iety

Semi-dwarf White— gamma rays grain characteristics /32/ early Luchai-112 unchanged mutant

Semi-dwarf Tal lal.alhr a EMS 56-78 non- /6Ü/ mutant allelic (T.R.) o DBWt G

Spontaneous Collection 64-1O4 allelic /41/ dwarfs (11) from North- to DSWB eastern India

(Reported by P.Pookamana) /53/

6S No.1367 Nlaw Sanpha gamma ray 124 early,short stature /16/ g n aw T (160)

US No.1368 II II gamma ray 124 /16/ (16O)

GS No.2424 Khao Dawk qamma ray 130 short stature /16/ Mali 105 (145)

SS No.3094 1* II 5 13 gamm y ra a early,short stature . /16/ (145)

LA 29 Leuang Nf 1O8 short stature 724 / mutant(19 2 n Aw ) (132)

LA29 gamma ray 9O /24/ mutant(2) (132) mutant (3) Nf 96 / 5/ (132)

(Reported by J.N.Rutger) /38/

Calrose 76 Calrose O 9 gamm y ra a sd 1 confers 15/C yield /3S/ (120) advantag crossen i e s CI 11045, M5 gamma ray 9O sd2=sdl no yield advantage /II/ CI 11046

268 CI 11O47 Maxwell gamma ray 9O no yield advantage /ll/ (12O)

CI 11O4B 140- WC 3 gammy ra a 110 short stature, water /ll/ (130) weevil tolerant

CI 11049 Calrose gamma ray 75 sd?=sdl semidwarf source, /ll/ (120) narrow leaves

CI 11050 Tsuru Mai gamma ray 85 narrow leaves /I I/ (120)

D 24 Calrose gammy ra a 100 sd4 semidwarf source /38/ (120)

D 38 Coa lus gammy ra a 9O sdl lodging susceptible. /38/ (120) o yieln d advantage

0 66 Calrose gamma ray 100 sd2 semidwarf source /38/ (120)

DD 1 (Calros6 e7 80 sdlsd2 double dwarf /38/ x D66)

DD 2 (Calros6 e7 80 sdlsd4 /38/ x D24)

DD Z (D24 x D66) 90 sd2sd" 4 /38/

M 9 (/IRBxCS-M3/ 90 sdl 15X yield advantage /ll/ x 10-7)

M 401 Terso gammy ra a 90 X yiel20 d advantage /ll/ (120)

Shor6 S t S6 gamma ray 9O o yieln sdd l advantage /ll/ (120)

Short Labelle gammy ra a 85 sd?=sdl lodging resistant /38/ Labelle (HO) long grain

Short Mars Mars gammy ra a 85 sdl lodging resistant /38/ (110)

(Reported by Riyanti Sumanggono) /42/

A23/PsJ/72K Pelita I/I gamma ray 9O high yielding potential /54/ (115) resistant to leaf blight A227/2/PsJ A23/PSJ/72K O gamm9 y ra a resistan BPHo t , good /43/ (9O> in upland conditions

A227/3/PsJ II II M 0 gamm9 y ra a resistanH BP o t /43/ (90)

269 A227/5/PsJ A23/PsJ/72K 5 gamm8 y ra a resistan BPHo t , /43/ <9O) high yielding

A227/6/PsJ 0 gamm9 y ra a resistant to BPH,good /43/ (9O) p ilanu n d conditions

A329/PsJ gamma ray 84 resistan H BP o t /43/ (9O)

A349/3/PsJ gamma ray 9O resistan BPHo t , good /43/ (90) yielding

A366/3/PsJ gamma ray SO resistant to BPH, good /43/ (90) yielding

171-18/396 (IR26xA38) 71 , " /43/ (100)

163- 12/ Mudgox (A20) 79 , " /43/ 4O3-3 (105)

(Reported by H.Yamagata) /49/

KUR 1 Simbozu x-ray 65 /49/ (86)

KUR 2 x-ray 70 /49/ (86)

KUR 3 1 6 y x—ra /49/ (86)

KUR 4 gamma ray 64 early maturing /49/ (86)

KUR 5 2 gamm5 y ra a erect type, stiff straw /49/ (86) early maturing

KUR 6 gamma ray 73 stiff straw, early /49/ (86) matur ing

KUR 7 2 gamm7 y ra a 1 rec. early maturing /49/ (86)

KUR 8 gamma ray 73 erect type, dense /49/ (86) panicle, small grain

KUR 9 gamma ray 75 early maturing /49/ (86)

KUR 10 0 gamm6 y ra a /49/ (86)

270 1 1 R KU Gimbozu 5 7 gamm y ra a early maturing /49/ (B6)

2 1 R KU 5 7 gamm y ra a /49/ (86)

KUR 13 Makaba El 79 erect type,early /49/ (91) maturing,high yield KUR 14 El 76 erect type,early /49/ (91) maturing,siightly long panicle,high yield Reimei Fujiminori gamma ray 74 leading variety /IS/ (87) in Japan Hokuriku Koshihikari gamma ray 74 promising parental /50/ (85) gine for the breeding of short culm varieties

Jukkoku 78 many tillers

Triticale x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x :< x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x i : x x

(Reporte C.J.Driscolly b d ) /15/ 1-36 S EM Beagle Vl5/

1-13 S EM Dr-IRA /15/

1-29 Dr-IRA gamma ray /15/

1-26 Beagle gamma ray /15/

Triticum aestivum L.

abas(Reporter Ba . )Z y b d /55/

BKT-8001 (Fe442 Mut. 6O good quality and / 9/ x Bezostaya) (90) winter hardiness

Karcagi Karcagi 522 gamma ray SO 1 dom. /47/ 2 A52 M (12O-125)

Mv 8 (Bezostaya gamma ray 80 strong straw,good /40/ Mut.x Ranka quality,exellent Mut.3 ) yielding,leading variet n Hungari y y

271 a-Bat Mu n i-ut B-1201 5 7 gamm y ra a lodging resistant (100)

Putative Complex gamma ray 15—85 Rht3 dwarf,semidwarf / type/8 s Apomictic crosses (4O-120)

R 12—Mut. Rannaya 12 O 7 gamm y ra a good quality,lodgin/ /B g (10O) resistant

(Reported by C.J.Driscol) /15/

Berse 3 Bersee2A e EMS 103 Rht7 /15/ Mut.C-1-l

(Reporte y K.Filevb d ) /56/

Altimir 67 Scorospelca radiation 8O lodging and desease /17/ 35;:Mexipak) resistant,ear ly ripening,productiv, good quality

(Reported by B.Biorgi) /52/

5 11 t S Strampelli gamma ra4 9 y resistan o lodgint g /2

6 11 t S Nf 04 » » n /29/ (102)

1 12 t S Nf 85 " " " /29/ (102)

Mar a Akagomoughi SO " " " /30/ m i r To (Norm 1O 75 RhtlRht2 resistant to lodging /13/ x Brevor 14)

(Reported by C.F.Konsak) /21/

CI 12696 Bur t 0 10 rht6 /48/ (100)

CI 13988 Mar fid EMS 55 Rht? /21/ (120)

CI 15076 Burl gamma ray 65 rht4 /21/ (100)

CI 15233 Centana 5 7 Rht?Rht2 /21/ (11O)

272 CI 17042 55 RhtlRht2 /31/ (110)

CI 17241 Chris DES BO rec. /19/ (120)

CI 17324 Burt 68 Rht2rht6 / 4/ (100)

CI 17329 Burt 7O Rhtlrht6 / 4/ (1OO)

CI 17335 50 RhtlRht2rht6 / 4/ (100)

CI 17393 Centana 75 Rht r Rhto l 2 /31/ (110)

CI 17394 78 Rht r Rhto l 2 /31/ (110)

CI 17398 75 Rht?Rht2 /31/ (110)

CI 17689 Magni1 4 f MNH 70 dom. /21/ (120)

CI 17786 Burt 4O Rht?rht6 / 4/ (100)

WA 4569 Burt gamma ra0 6 y /21/ (100) WA 4831 Kacag2 52 i gamma ray 60 dom. /47/ (120)

WA 5859 Mar fed EMS 65 rec. /21/ (120)

MA 5860 EMS 55 rec. /21/ (120) WA 6270 MNH 70 rec. /21/ (12O)

WA 6271 Bezostaya 1 MNH 55 rec 723 / =Karli1 k (95) WA 6272 MNH /23/ =Karli2 k

WA 6275 Mar fed EMS 60 dom. /21/ (120)

WA 6327 WA 6021 MNH 75 rec. /21/ (130)

273 (Reporte y A.Tulmanb d n Neto) /44/

Ticena-1 IAC-5 gamma ray 86 744 / (108)

Tiscena-2 IAC-5 gamma ray 7O 14 days earlier than /44/ (108) control

Tiscena—3 4 7 gamm y ra a 744 / (108)

Triticum duru. L m XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

(Reporte y K.A.Filevb d ) /56/

3 23 o N 65/I-N gamma ray 65 Rht cold and lodging /56S14/ (gameto- (122) resistant, BA-insen- phyte) sitive

65/2 105 cold and moderate /56, 14/ (122) lodging resistant, BA-sensitive

15/4-2 (788x/BDx gamma ray 72 Rht productive, /56/ Val/) (85) lodging resistant, BA-insensitive Lose6 7 n (788xCaste l5 9 gamm y s.domra a . productive,lodging /57/ porziano) (135x90) and cold resistant, BA-sensitive Zeverjana (/788;

(Reported by B.Siorgi) /52/

Augusto (CpB132 85 lodging resistant, /46/ x BrA145) high yielding

Cp C 48 Capelli Nth 105 moderate lodging /39/ (14O) resistant

2 13 CB p It O 9 Nth s.dom. lodging resistant /10/ (140)

Cp B 144 II x-ra3 10 y ii ii /29/ (14O)

274 Creso 0 1 n i (Nor lodging resistant, /10/ x X) high yielding

Ga B 124 Garigliano x - ray 110 moderate lodging / 6/ (130) resistant

5 14 GrifonGA r i Nf HO /46/ (130)

Mida (Nor in 1O lodging resistant, /29/ x X) high yielding

Tito II II / 6/

(Reported by C.F.Konzak) /21/

W A 6G3O Leeds 75 Rhtl /21/ (125)

WA 6274 EMS 75 /21/ (125)

WA 6521 K6800707 MNH 85 /21/ (125)

275 LIST II

List of Semi—dwarf cereal stocks

Breeder d Institutean s s

;•: x x x :•: x x x x x x x ;•: x x x x x x x x x x x x x x x x x x< X: X X X X X X X X X X X X X X X X X X X X X X X X X X X M X X X X X X X X X X X X X No Breeder (s) Institute x x x x x x x x x x x x x x x ;; x x x x x x x x x x x x x x x ;•: x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

/ /! Andersen A.J. Research Establishment, Riso, D e n m a r k

/2/ Awan M.A., A.A.Cheema Nuclear Institut r Agricfo e . £< Biology Faisalabad, Pakistan

/ Alla/4 n R.E. USDA-ARS, PullmanA , US WA , .

/5/ Klyprayong B. Rice Research Institute, Departmenf o t Agric. Bangkok, Thai land.

Divisione BIOAGR. ENEA - Dip. FARE, CRE Casaccia, Rome, Italy

/7/ Barabas Z., P.Erdei Cereal Research Institute, Szeged, Hungary

/8/ Barabas Z. , Z.Kertesz Cereal Research Institute, Sseged Hungary

/ Bek/9 . F e Cereal Research Institute, Taplanszentkereszt, Hungary

/10/ Divisione BIOAGR. ENEA - Dip. FARE, CRE Casaccia, Rome, Italy /ll/ Carnahan H.J. CCRRF, Biggs, CaliforniaA US , /12/ Chaudhary B.C. et al. B.B. Pant University of Agric.and Tech. Pantnagar, U.P. India

/14/ Divisione BIOAGR. ENEA - Dip. FARE, CRE Casaccia, Rome, Italy /15/ Driscoll C.J. Waite Agricultural Research Institute Austral ia /16/ Khambanond. P a Rice Research Institute, Dept f Agric..o , Bangkok, Thai land /17/ Savo. vP Institute of Genetics, Sofia 1113, Bulgaa i r /IS/ . Futsuh«ral t e . Y a Aomori Prefect, Agriculture Experimental Station, Japan

277 /19/ Heiner R.E. NAFB, BerthoudA US , CD ,

/2l/ Konzak C.F. Washington State University, Pullman, USA /22/ f olding M.F. Oregon State University, Pendleton, Oregon, USA /23/ Lu k y an en l'o USSR

/24/ Phambanonda P. Rice Research Institute, Department . SarigabutA r of Agric., Bangkok, Thai land

/26/ Mchenzi. eR Agriculture Canada, Winnipeg, Canada

/27/ Matchett R. Northrup-King Co., Woodland, California, USA

/2B/ Mohanty H.K., S.R.Das Orissa University of Agric. l> Technology, Bubhaneswar, Orissa, India

/29/ Divisione BIDABR. ENE Dip- A . Fare. CRE Casaccia, Rome, Italy

/30/ Michaelles .... Private Firm, Bologna, Italy /3l/ McNeal F.N., M.Berg USDA-SEA, Bozeman, Montana, USA

/32/ Narahari P. BARC, Bombay, India

/33/ Nilan R.A. Washington State University, Pullman USA

/34/ Quick J.S. Colorado State University Fort Collins, USA

/35/ Anderson—Clayton Co. of Phoenix, Arizona, USA /36/ Narahari P., D.C.Joshua, BARC, Bombay, India N.S.Rao

/37/ Reddy B.M., T.P.Reddy Osmania University, Hyderabad, India /3S/ Rutger J.N. University of California, Davis, USDA-SEA AR.A ,US

/39/ Divisione BIOABR. ENEA - DIP. FARE, CRE Casaccia, Rome, Italy

278 /40/ Ssilagyi Gy , . D.Szalai Agric. Inst., Hungarian Acad f Scienceso . , y r Martonvasar a g . n u H ,

/41/ Sin. al g t V.Pe . Indian Agricultural Research Institute New Delhi, India /42/ Riyanti S., Moch.Ismachin Centre for The Application of Isotopes and Radiation, Jakarta Selatan, Indonesia

/43/ Mugiono e ApplicatioCentrTh r fo e f Isotopeo n s and Radiation, Jakarta Selatan, Indonesia /44/ Tulmann-Neto A. Centr e Energid o a Nuclea a Agriculturan r , Piracicaba S.P. Brazil /45/ Ullrich S.E. Washington State University, Pullman, USA /46/ Divisione BIOAGR. ENE Dip- A . FARE, CRE Casaccia, Rome, Italy /47/ Vigas. P i Ministry of Agriculture and Food, Budapest, Hungary

/4G/ Vogel O.A. USDA-SEA, PullmaA n WA.US , /49/ Yamagata H. et al. Kyoto University, Kyoto, Japan

/50/ Samoto S. et al. Hokuriku National Experimental Station, Japan /5l/ Bale M.D. Plant Breeding Institute, Maris Lane, Trumpington, Cambridge, United Kingdom

/52/ Divisione BIOAGR. ENE Dip- A . FARE, CRE Casaccia, Rome, Italy /53/ Pookamana P. Breeding Division, Rice Department, Bangkok, Thai land /54/ Ismachin Noch. Centre for The Application of Isotopes and Radiation, Jakarta Selatan, Indonesia /55/ Barabas Z. Cereal Research Institute, Szeged, Hungary /56/ Fi lev K. Institut f Geneticseo , Sofia 1113, Bulgar ia /57/ Fi lev K., Z.Avramova Institut f Geneticseo , Sofia 1113, Bulgaa i r

279 /5B/ . AwaA . M n Nuclear Instituit Agnc.r fo e & Biology Faisalabad, Pakistan

/59/ Carleton A.E-, Clark,D. Western Plant Breeders, Bozeman, Montana« USA /fcO/ Reddy G.M., A.Padma Osmania University, Hyderabad, India x x ;• x x x x x :•. :: x x x ;: :: x x x x x x x :t x x x x x x x x x x x x x x x x x :; x x x x x x x x x x x x x x x x x x x x x x x x x ;: x x x x x x :: x Revise - T.hawai y b d , 1983. - A.Miete and M.Maluszynski, 1984. x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x : % x ; .x

280 CONCLUSION RECOMMENDATIOND SAN S

Topics of the discussions, brief summaries and some views of the participants of the RCM are recorded below for future development of the programme:

. 1 GA-sensitivity

Three indice r GA-sensitivitfo s y were considered ) GA-treate(a : d - GA-untreated, ( b) GA-treated/GA-untreated and (c) (GA-Treated - GA-Untreated)/GA-untreated. Significanc f theso e e indicen i s relatio o researcnt h objective wil e examineb l Narahariy b d .

. 2 Change n agronomii s c traits associated wit mutantD S h s

In order to evaluate SD genes for cross breeding, their phenotypic effect agronomicalln o s y important traits other than plant heigh te clarifiedb hav o t e mentiones A . d latere , th som f o e associated t directlchangeno e ar sy ascribe e primarth o t dy effect (including pleiotropic effects) of the SD gene, but are ascribed to secondary effects. Althoug e primarth h d secondaran y y effectv ma s not be separable, their discrimination is of considerable significance for the precise characterization of mutants. Comparison between two near~isogentc lines (one with SD gene and another without S De sam th gen e n i egeneti c background e firsth e ts i )th ste f o p offeanalysisy ma r t littlbu , e contributio e discriminationth o t n . One metho s describewa d Galy d Flinthab d an e t ma thi s meetinge Th . method compares response f neao s r isogenic line n thei(i s r studies Rht3 and rh±3 near isogenic lines) to the artificial manipulation y characteke oa f r associated with semi-dwarfness (e.g.,crain number per spike) on other characters (e.g., TOT and grain N level). Comparing response f isogenio s c e artificialineth o t s l manipulation (e.g., different degree f de-grainingo s ) provides informatioo t n discriminate primar d secondaran y y gene effects. e neath TG rf Wo isogenic lines Rhtß and rhtß showed the same value at the same numbe f grains/spikeo r , thu e differenth s t TGW values betweee th n o inter-grait e du Rhtrhtd e an ^ar ^ n competition e causeth y b d increased spikelet fertility. The low grain N level was partly ascribed to the stronger inter-grain competition in Rht lines. Such a method would provide valuable information, but its application may be limitee conditionth y b d f artificiao s l simulation.

Another possible approac s comparisoni h f neao s r isogenic lines of one SD gene in different in genetic backgrounds (2m isogenic lines required), with proper statistical processing of data obtained, e.g., path co-efficient analysis. This method may also provide information on "modificability" (Konzak paper f individuao ) genesD S l .

Nitrogen fertilizer response; Many reports indicate different relational curves between N dose and grain yield. N dose x grain yield curves obtaine n testi d s using near isogenic lines will provide interesting results, as shown by jome of the programme participants. Biomass production and harvest index will be important characters in investigation, in addition to the yield components. Artificial preventio f lodginno a "simulatin s i g g condition" wher e effecth e f o t increased lodging resistance by reduced plant height is nullified.

281 Cold tolerance: Californi D ricaS e varietie protectee sar d against cold e lowedamagth ry b epositio f theino r panicle primordia (under deep waterstagee th t s)a before culm internode elongation. The same is the case for the variety Reiraei (Japan). This example demonstrates a typical secondary effect.

Root system evaluation: Becaus s suspectei t i e d that somD S e mutant may also possess modified root systems, studies to compare the root system originamutante f so th d san l varieties woule b d informativ d shoulan e made b dlaboratorien ei s having facilities suitabl sucr fo eh studies. Comparison numberf so growtd san h rates of primary and secondary roots in seedling stages via laboratory tests may be more widely applicable. Studies using lysimeters where available may be useful.

Reaction to biological stresses; When possible, SD mutants should be compared with their initial variety for response to stresses, suc droughs ha minera, t l imbalanc d salinitean alsd an yo for their diseas pesd ean t reactions. Ofte nchangea d plant architectur y presenema changea t d environment whic y favohma r disease or pest development, thus requiring incorporation of additiona morr lo e effective gene diseasr sfo pesr eo t resistance. It was pointed out that rain-fed rice requires more breeding and research input, and that the significance of SD rice varieties or lines under rain-fed condition in the tropics has to be explored.

3. Interactions between SD genes, environment and background genotypes Interaction genegenD D S S ex f genD s, o S eenvironmenx d an t SD gene x background genotype x environment are relevant for the evaluatio geneD S cross-breedingf n no si . Interactione b y sma specific or non-specific. Investigation of these interactions may identify modifiers of SD genes. Studies by using near isogenic lines are essential for obtaining precise information about the interactions. When different heading date properle sar y taken into account, studie availablf so e varieties carrying already identified alleles, e.g., DGW ricen G i provid n ,ca e information about interactions betwee gen e genetid th nean c backgroun environmentr o d . Expression alleleD S e specifia th f so f so c locus, e.g., DGWG, sd}, Jukkok Reimee allelD uth S sam e geneD d iS th e ean n ,i genetic background may be worth investigating, as is being done in wheat. 4. Specific conclusions and recommendations s recognisewa t I d) a thastudiee th t s conducte consequenca s a d e of followin e recommendationth g e th f firso e th M tRC f s o programm outlines ea alreadd Figha n i d, .1 y contributed useful results in the evaluation of SD mutants and SD genes. participante Th ) b s agree exchango t d e their materiao t d lan participat internationan ei l co-operative investigationr sfo genotyp eenvironmenx t interaction outlines sa Fign i d. .2

282 r standardizatioFo ) c f traino t assays e s agreeth wa t y ,i b d participant standardizee sth that) (a ; d methods coule b d differen differene th r fo t t standardizee cerealsth ) (b ; d methods should he as simple as possible; (c) the standardized method e partlb n ysca modified depending upolocae th n l conditions (details given below). d) Methods for evaluating SD genes at early generations after crossing, as proposed in Fig. 1, should be developed and incorporated in research carried out within the programme.

283 Figure- 1 OUTLINE OF METHOD OF EVALUATION OF SD GENTS

Genetic: Tester Linos. •Gene Locatio Linkagn& e Test I -frHomeoollelis polyploin i m d Crop -»Gen Polyploid. x e y Interaction First Stef o p Identification Induction Determination geneD S w sofne New -fCytoplasmic- Interaction and Evaluation of Numbef ro Agronomi& c_ through -»•Associated Effect AlloleD S f so s Collection •»•Major SD Genes Allolism Test • SD —• characteri- and their Genes d discriminatioan pleiotropif no c of . zation of (inter— and SD Mutants Isolation Effects and Effects of linked MutantD S s intra-allelic) Genes (compariso isogenif no c lines of one SD gene or copulations with 3D gone and without. SD gone in the N> same background on average)* 00 •ft Assessment "Cleaning-up" Second Step •»Gene x Back round Genotype of Agronomic of SD Mutants of Evaluation Interaction (isogenic- Lines) Characteri& - Potentiaf o l -• Gen eBackgroxinx d Genotypex SD Mutants zatioD S f no Mutants. Environment Interaction (isogenic- linos) Gen eEnvironnenx t Interactions (in the same or different genetic backgrounds) î See Figure 2

Drawn froConclusione th m Kccoranendationd san Cereaf o firse M th ltRC f o sSemi-dwar f Programme (March 1981) FIOOBÏ 2 A PROPOSE!) SCHSKS FOR ISYESTIGATIHG IHTERACTIOKS BETT/ESN GENES, BACKGROUND GENOTYPES AND ENVIRONMENT

Combination 8d X 84 T x X sd. Z x „ sd (SD geneà l ' 1 f background) 1 1 "T P2 (or BC,) SD- SD- SD- Comparison À's or Eore sesrre. eegre. eegre. comparison advanced popul* popul. popul . between SD & generations ' non-Si) plants or • 1 Seperation of SD and — > non-SD }x A }\ More SD Son-Si SD 1 Compariso" A n advanced comparison oo générations I>opul . popul • popul . betwee& D S n non-SD populo. 4 1 Interaction .-X •V id2-3 rS-Z

Comparison A » SD population (plants) va non-SD population in «ach of one gene x one background genotype

Compariso - gen BetweeI D B nS ez severa e on n l background genotypes case comparison o d , sd..-nA sd.-a Xv s Tsd--v Z etc. Comparison B_ • Between one background genotype z several SD genes based on comparison A, scL-X vs sd„-X vs sd.-X etc. Compariso • Comparison C n undeB & r A differens x environmentat l conditions. Similar methodappliee b z r genma sdfo z egen e interactions. Problems t (l) Single croes or backcross(es) ? (2) In which generation ? (3) Ho« to quantitatively express interactions ? (4) Ho o desigwt n field experimeno analyzt w ho ed datan t? a ( 1 and 2 pertain to rocombination of genes of chromosome carrying SD gene) Recommended standard procedures for rice SD line evaluation

firsa s A t step characteristice ,th s listed below shoule b d investigated. Observation measurementr so s shoul made b dtrun eo e breeding mutant lines only, with a minimum of 20 plants, in comparison with the parental and/or 1 or 2 top standard varieties. The results should then be recorded on a line (variety) basis. 1. Coleoptile length - use blotter "sandwich" method of Myhill and Konzak (1967fulle th yt ) a extende d seedling stage (about8 days) and, in addition, emergence percent in prevalent local conditions, e.g., under soil, in water, or in puddled soil, whatever is the local practice.

. 2 Plant architectur flowerint ea maturityd gan .

) Plan(a t habit after flowering, erec= score 1 ts da (cul m angles less than 30° from perpendicular); 3 = intermediate (angle about 45°); 5 = open (angle about 60°); 7 = spreading (angle more than 60° but culms not resting on ground); 9 = procumbent (culm on its lower part rests on ground surface).

) Between—plan(b within-pland tan t heading synchrony scores a d 1 (duration of heading less than 5 days), 3 (6-10 days), and 5 (more than 10 days). (c) Number of effective (grain bearing) tillers at maturity in standard cultivation conditions, recorded as number/m^ plants0 2 r ope .r 3. Culm length, measured after heading in centimeters from ground level to the base of the panicle. . 4 Flag leaf angle, measure shortlr o t da y after flowerine th s ga angle between the flag leaf blade and the culm axis, and scored as 1 • erect; 3 = intermediate; 5 =» horizontal; and 7 » descending.

5. Panicle at maturity - ) Lengt(a paniclef ho , measure centimetern di s frobase mth e to the tip.

(b) Weight of panicle, or number of fully developed grains per panicl(tallese th f eo t culm). (c) Panicle exsertion above the flag leaf sheath after anthesis is scored as 1 » well exserted - the panicle base appears away above the collar of the flag leaf; 3 * moderately well exserted - the panicle base is above the flag leaf collar; 5 « just exserted - the panicle base coincides with flag leaf collar; 7 » partly exserted - the panicle bas slightls ei y beneat flacollae e hth th g f ro leaf blade; 9 - enclosed - the panicle is partly or entirely enclosed withi leae nth f flasheate th g f hleafo .

286 6. 1000-graln weight

. 7 Headin d maturitan g y dates, recorde s numbea d f dayro s after sowing in standard cultivation practices.

8. Tolerance to stresses (drought, high humidity, cold, high temperature, etc.), recorded only if remarkably different from parenta standarr lo d variety. 9. Resistance to pathogens and pests, recorded only if remarkably different from parental or standard variety.

10. Agronomic performance

) Lodgin(a g resistanc maturitt a e y stron= score 1 o s (n ga d lodging); 3 =• moderately strong (most plants leaning; 5 = intermediate (most plants moderately lodged); 7 = weak (most plants nearly ver « flat)9 y d wea;an k (all plants flat). (b) Grain yield recorded as g/m^ or per 20 plants.

287 Recommended standard procedurer fo s wheat and barley SD line evaluation (see also IAEA TECDOC 268)

Induced mutants will usually be observed in M„ or M, generation. Many SD mutants will be disregarded on general agronomic grounds. The remaining ones will be selfed and further investigated in the following generation.

The trial plot size should be at least a one meter row with a minimum of 20 plants. Trials should include the parental genotype and standard varieties for more meaningful comparison.

Initial characterization should include:

1. Culm length, measured in cm from ground level to base of spike . 2 Head length, cm,bas p (excludinf spikti o e o t e g awns) 3. Heading date, days from sowing to 50% spike emergence . 4 Maturity time, days from sowin o harvest g t ripeness 5. Spike exertion, total, partial, none 6. Heading synchrony, good, intermediate, poor 7. Plant habit, erect, normal, spreading . 8 Environmental stress tolerance, note response o droughtt s , heat, water logging, etc. when remarkably different from parental r standaro d variety 9. Disease and pest resistance, note reactions to diseases or pests when remarkably different from parental or standard variety 10. Lodging resistance, % plot lodged and angle of lodging, 9 upright, 0 flat 11. Yield r plope t ,g (1000 grain weigh d voluman t e weighte b als o t o iiclude r Triticale)fo d .

288 LIS PARTICIPANTF TO OBSERVERD SAN S

. A AWAN . M , Nuclear Institut r Agriculturfo e e & Biology, Jhang Road, P.O.B8 12 . Faisalabad, PAKISTAN.

BALAL. S . ,M Rice Research and Training Project FAO Building Room 4l3n Dokki, Cairo, EGYPT.

BARABAS, Z. Cereal Research Institute 6701 Szeged, P.O. Box 391, HUNGARY.

BARI. G , Atomic Energy Agricultural Research Centre, Tandojam Sind, PAKISTAN.

BUDDENHAGEN, I. Department of Agronomy and Plant Physiology, Universit f Californiao y , Davis, California 95616, USA.

DRISCOLL, C. J. The University of Adelaide Waite Agricultural Research Institute Department of Agronomy, Glen Osmond SOUTH AUSTRALIA 5064

FILEV, K.A. Institute of Genetics Bulgarian Academ f Scienceo y s Sofia 1113, BULGARIA.

GALE. D . ,M Plant Breeding Institute Maris Lane, Trumpington Cambridg 2 2LQCB e , UNITED KINGDOM

GIORGI. B , ENEA, FARE/FIOAGR. C.R.E. Casaccia, C.P. 2400 00100 Rome, ITALY

GUSTAFSSON. ,A Institut f Genetico e s University of Lund Sölvegatan 29 S-223 62 Lund, SWEDEN

. H HU. ,C N.F. Davis Drie Elevator& r , Inc. P.O. Box 425, Firebaugh, California, 93622, USA.

JENK1NS. C . ,B Dessert Seed Company, Inc. Research Station, 1072 Industrial St., Salinas, California, 93901, USA.

KHAMBONODA. ,P Departmen f Agricultureo t , Rice Division, Bangko THAILAN, 9 k D

MOON. P . ,H Department of Agronomy University of California Davis, California 95616, USA.

289 NALEPA. S , Dessert Seed Company, Inc., Research Station, 1072 Industrial St., Saunas, California, 93901, USA

NARAHARI, P. Biology and Agriculture Division, Bhabha Atomic Research Centre, Trombay, Bomba 0 08540 y , INDIA.

PETERSON, M.L. USDA-SEA-AR, Universit f Californiao y , Davis, California, 95616, USA.

QUALSET, C. 0. Agronomy Department, Universitf o y California, Davis, California, 95616, USA.

REDDY, T.P. Departmen f Geneticso t , Osmania University, Hyderaba 0 00750 d , INDIA.

RIYANTI SUMANGGONO, e ApplicatioCentrth r fo e f o n A. M. Isotopes and Radiation, Kotakpos 2, Kebayoran Lama, Jakarta Selatan, INDONESIA.

RUTGER, J. N. USDA-ARS, Agronomy Department, University of California, Davis, California 95616, USA.

TULMANN NETO. ,A Centr e Energid o a Nuclea Agricultura n r a Caixa Postal 96, 13.400 Piracicaba S.P., BRASIL

ULLRICH, S. E. Washington State University, Department of Agronomy and Soils Pullman, Washington 99164, USA.

YAMAGATA, H. Kyoto University, Faculty of Agriculture, Kitashirakawa-oiwakecho, Sakyo-ku Kyoto 606, JAPAN.

SCIENTIFIC SECRETARY:

KAWA. T I Plant Breedin d Genetican g s Section Joint FAO/IAEA Division, VIENNA

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