Hereditas 88:IOI-I05 (1978) Inheritance of tolerance to low soil pH in barley

OLAV STQ)LEN and SIGURD ANDERSEN Department of Crop Husbandry and Plant Breeding, Royal Veterinary and Agricultural University, Copenhagen, Denmark

STQLEN, 0. and ANDERSEN,S. 1978. Inheritance of tolerance to low soil pH in barley. - Hereditas 88: 101-105. Lund, Sweden. ISSN 0018-0661. Received November 30, 1977 Progenies after crosses between 3 pH tolerant and 2 non-tolerant barley varieties were evaluated in field experiments laid out on acid soil (pH 4.6, KCI). The results showed that the tolerance to high soil acidity is controlled by a single dominant gene, Pht. The gene is located in chromosome 4, and is linked to the gene K (hooded barley). The recombination value is approximately 25 units.

Olav Stden, Department of Crop Husbandry and Plant Breeding, ThorvaldsensvejlO, DK - 1871 Copenhagen, Denmark

Although barley grows best on soils with fairly varieties see ST~LEN(1965, 1972). The F,-hybrids high pH, varieties which tolerate lower soil pH of all crosses were grown in greenhouse and have been found (VAN DOBBEN1959; GALJTHIER selfed for the production of the F,-generation. The 1958; VANESSEN and DANTUMA1962; CHIASSON F,-population called B was composed of prog- 1964; STOLEN1965). enies from crosses between Scots Bere and 14 Fou et al. (1965, 1967), MACLEANand CHLASSON lines carrying various marker genes. The lines (1966), MACLEODand JACKSON(1967) and REIDet were obtained from Arne Hagberg, Swedish Seed al. (1969) showed that some barley varieties are Association, Svalov. not only tolerant to low soil pH, but more The F,-population A was tested in 2 field specifically to high concentrations of aluminium in experiments performed on a medium light clay low pH soils. REID(1970) in his work with winter soil with pH of 4.6 (KCI). The experiments nos. I barley found the Al tolerance in the varieties and 2 were randomized block design with 5 and 6 Dayton and Smooth Awn 86 to be controlled by a replications, respectively. Each plot, bordered by single dominant gene. spring-wheat plants, comprised 50 plants equally This report presents data on the inheritance of a distributed in 5 rows 2 m long and 25 cm apart. gene for tolerance to high soil acidity and its location in the barley genome. Experiment I. -The F,-seeds of (A) were planted in April 1974. The material was harvested when the plants in a cross or a parental line had Materials and methods developed to the heading stage. The plants were cut at ground level, and oven-dried at 100°C fai 21 F,-populations. - During the winters of 1973/74 hours, after which the dry weight of each plant and 1974/75 diallel crosses were made between was recorded. the three pH-tolerant barley varieties Scots Bere, Hordeum macrolepis, Sigurdkorn and the two Experiment 2. - Seeds of (A) were again planted in non-tolerant varieties Bonus and Fero. This rnate- April 1976. In this experiment the plants were not rial was called population A. For details of the harvested, but classified for tolerance in the field. 102 0. ST0LEN AND S. ANDERSEN Hereditas 88 (1978)

Table I. Dry-matter yield per plant (g) in a 5 x 5 Table 2. Segregation in F,-populations after cros- diallel cross of barley ses between three pH-tolerant and two pH-non- Means are average of approximately 300 F,-plants tolerant barley varieties Expected ratio 3: I. T =tolerant, N = non-tolerant 33 75 262 276 592 Cross Obs. xz Total P 33 16.1 17.0 12.4 12.1 19.1 no. of x2 values 75 11.6 13.4 12.9 15.0 plants 262 5.4 5.3 13.5 ~~ 276 3.4 12.3 Bonus x T 220 0.001 592 15.5 H. rnacrolepis N 74 0.003 0.004 0.95 to0.975 I 294 Fero x T 215 0.073 H. rnacrolepis N 77 0.219 0.292 0.50 to 0.75 P 292

Hr I ati ve Bonus x T 201 0.45 I frrquenc,y Sigurdkorn N 80 1.353 1.804 0.10 to0.25 z 281 Fero x T 206 0.337 Sigurdkorn N 80 1.010 1.347 0.10 to0.25 0.34 .. x 286 1 Bonus x T 22 I 0.128 11.32 -, IK S. Bere N 66 0.461 0.589 0.25 to 0.50 z 287 Fero x T 209 0.141 S. Bere N 77 0.423 0.564 0.25 to 0.50 P 286

0 262 x 276

0 262 Tall and vigorous plants were classified to be of A 276 the tolerant type. Short and weak plants (often with necrotic spots on the leaves) were classified as susceptible to low soil pH.

Experiment 3. - F,-seeds of (B) were planted in April 1974. The distance between individual plants was lox 10 cm. In July the plants were pulled from the ground and sorted into 4 groups: (I) Well developed plants with marker genes. (2) Well developed plants without marker genes. (3) Small plants with marker genes. (4) Small plants without marker genes. !I . !I8

0. Oh Experiment 4. - In 1976 seeds of (B) were planted individually in glass test tubes (I00 mm long, (I. 04 diam. 28 mm). The tubes were filled with the same soil as described above. When 314 of the plants had developed roots down to the bottom of the tube, classification of the material was under- 0 taken. Plants which had filled the tube with roots 0 2 4 h 8 10 I? I$ I’ I .in t dry-we L gti t in granmirs were classified as pH-tolerant and those with weak rootdevelopment as pH-susceptible. After Fig. I. Plant dry-weight distribution of parents and Fz after a cross of 2 pH-non-tolerant this classification the material was then trans- varieties. The plants were grown in soil with pH planted to pots and grown until maturity when of 4.6. sorting for marker genes took place. Hereditus 88 (1978) TOLERANCE TO p~ IN BARLEY 103

Relative f rcquency 0.14 h

(1 2 4 8 10 12 14 16 18 20 22 24 26 28

1’1 t dry-wc ight i ii grdium’s

Fig. 2. Plant dry-weight distribution of parents and F, after a cross of 2 pH-tolerant varieties. The plants were grown in soil with pH of 4.6.

Results table that there is a lack of non-tolerant plants when these are classified for a 3:l segregation. Experiment I. The non-tolerant varieties Bonus This is most pronounced in the crosses of Bonus x (KVL 262) and Fero (KVL 276) had much lower Sigurdkorn and Fero x Sigurdkorn. Probably this dry-matter yield per plant than the three tolerant phenomenon is related to the wilting of non- varieties Hordeum macrolepis (KVL 33), Sigurd- tolerant plants in the early germinating phase. The korn (KVL 75) and Scots Bere (KVL 592) cable best fit to the 3:l ratio was found in the crosses I). However, the average F,-plant weight covers Bonus x H. macrolepis and Fero x H. macrolepis. wide variation as is illustrated for each of the three Although the observed data from the crosses of types of crosses: non-tolerant x non-tolerant (Fig. Bonus x S. Bere and Fero x S. Bere do not fit the l), tolerant x tolerant (Fig. 2) and non-tolerant x expected ratio too well, the P-values from the tolerant (Fig. 3). chi-square test, ranging from 0.20 to 0.50, do not The variation of the F,-population of the non- indicate that the hypothesis of a 3:l ratio neces- tolerant varieties Bonus x Fero (Fig. I) and of the sarily should be rejected. A poor fit to the 3:l tolerant varieties H. macrolepis X Scots Bere segregation (P =O. 104.20) was found in crosses (Fig. 2) resemble the variation of the parents of Bonus x Sigurdkorn and Fero x Sigurdkorn although the data suggest a wider variation of the cable 2). F,-population. In the non-tolerant x tolerant In the F2-material of group B, grown in the field cross, exemplified by the cross between Bonus in 1974 (experiment 3), linkage between the gene and Scots Bere (Fig. 3), the variation of the F2- for pH-tolerance and the gene K (hooded) in population is similar to that of the tolerant parent. chromosome 4 was observed. The recombination Also in this type of cross, the F,-generation has a value between the two genes was estimated to be wider variation than either of the parents. 18.7 k4.4 in the field experiments Fable 3). When Analysis of variance confirms that the entries measured on the material grown in the greenhouse (parent and crosses) possess significantly (P. (experiment4)the recombination value was found 0.001) different tolerance to low soil acidity. to be higher, 25 k 1.7. Since the last crossing-over Results from experiment 2 carried out in 1976 value is based on the largest number of plants with when the plants were classified in the field are the smallest variation cable 3), the value of 25.7 presented in Table 2. It will be noticed from the is judged to be the most accurate. 104 0 ST0LFN AND \ ANDI-RSFN

0 .!f,L , 5Y?

0 Ih? A 592

0 2 5 h 8 I0 Ii I: If, I8 20 LL ?i Lh 28 30 l'I.iriL ilry-w~~ighrin grxm;es

Fig. 3. Plant dry-weight distribution of parents and F, after a cross of a pH-non-tolerant and a pH-tolerant variety. The plants were grown in soil with pH of 4.6

No linkage was observed between the gene for varieties, like those listed in Table 1, therefore tend pH-tolerance and the gene int"s (intermediate for to have equal single plant variation (Fig. 3) even 2rd, V.S. 6rd.) or the gene ert'':' ierectoid). though their means are significantly different (Table I). The crosses between tolerant and non- tolerant varieties indicate that tolerance is a dominant character since the distribution of the Discussion and conclusion F,-plants in these crosses was rather similar to that of the tolerant parent. Uniform field plots with low soil acidity are The visual classification of the F,-material in difficult to obtain and variation in the yield of Table 2 took into account not only the general single plants is often great. This may be due to the appearance of the plants but also necrotic spots fact that pH expresses a logaritmic function and which are fairly common on the leaves of non- therefore even small changes in pH values may tolerant plants. Still, it was sometimes difficult to drastically influence the availability or excess of decide which tolerance group an F,-plant be- elements in the soil. Tolerant and non-tolerant longed to. Despite these difficulties the data Hereditas 88 (1978) TOLERANCETO PH IN BARLEY 105

Table 3. Linkage between pH-tolerance in the variety Scots Bere and marker genes in chromosome 4

Place of Marker xz* xpB XZAB Recombination Number experiment gene of plants % SE

Field K 1.4 0.9 37 18.7 4.4 463 Greenhouse K 0.7 0.2 127 25.7 1.7 2311 Greenhouse intcs 6.0 4.2 0.2 free Greenhouse ertiSJ 0.2 2.8 2.9 free

from the present crosses showed a good tit to FOY, C. D., ARMINGER, W. H., BRICCLE, L. W. and REID, a 3:l segregation. From earlier work with this D. A. 1%5. Differential aluminum tolerance of wheat and barley varieties in acid soils. -Agrun. J. 57:413417 material (STBLEN 1972) and from the present FOY. C.D., FLEMING,A. L., BURNS, G. R. and ARMINGER, results we therefore conclude that the tolerance to W. H. 1%7. Characterization of differential aluminum toler- low soil acidity in the varieties tested is controlled ance among varieties of wheat and barley. - Soil Sci. Soc. by a simple mode of inheritance most probably by Am. Proc. 31 :5 13-52 I a single dominant gene. The gene, designated Pht, GAUTHIER,F. M. 1958. Tolerance of barley varieties to soil acidity. -Cereal News3:12 was located about 25 units from the gene K MACLEAN, A. A. and CHIASSON, T. C. 1966. Differential (hooded spike) in chromosome 4. performance of two barley varieties to varying aluminum Since this material was not tested specifically concentration. -Can. J. Soil Sci. 46: 147-153 MACLOD, B. and JACKSON, L. P. Aluminum tolerance to L. 1967. for tolerance Al-toxicity, it is not possible to of two barley varieties in nutrient solution, peat, and soil judge whether the present gene is identical to the culture. -Agrun. J. 59r359-363 ALP-gene found by REID(1970). REID, D. A. 1970. Genetic control of reaction to aluminum in winter barley. - In Barley Genetics 11 (Ed. R. A. NILAN), Acknowledgment. - The authors wish to thank Dr. M. H. Proc. 2 Int. Barley Genet. Symp., Washington State Univ. Poulsen and Dr. S. N. Mishra for criticism of the manuscript. Press, p. 409413 REID, D.A,, FLEMING,A. L. and FOY, C. D. 1971. A method for determining aluminum response of barley in nutrient solu- Literature cited tion in comparison to response in al-toxic soil. -Agron. J. 63: ca0403 CHIASSON,T. C. 1964. Effect of N, P. Ca, and Mg treatments STOLEN, 0. 1965. Investigations on the tolerance of barley on yield of barley varieties grown on acid soils. -Can. J. Plant varieties to high hydrogen-ion concentration in soil. -K. Vet.- Sri. 44:525-530 og Landbohgjsk. Arsskr., p. 81-107 DOBBEN, W. H.VAN 1959. A testing method to determine the STBLEN, 0. 1973. Breeding for pH tolerance in barley. - susceptibility of spring barley varieties to soil acidity. -Field K. Vet.- og Landbohgjsk. hsskr., p. 1-13 Crop Abstr. 12: 187-188 ESSENN,A. VAN and DANTUMA.G. 1962. Tolerance to acid soil conditions in barley. - Euphytica 11:282-286