s. Afc. J. Bot. 1998,64(6): 337- 34 5 337
Aneuploidy in Cenchrus cilliaris (Poaceae, Panicoideae, Paniceae): Truth or fiction?
N.C. Visser, J.J. Spies' and H.J .T. Venter Department of Botany and Genetics, University of the Orange Free State, P.O. Box 339, Bloemfontein, 9300 Republic of South Africa
Received 22 September 1997: revised /4 August 1998
This study confirms a basic chromosome number of x = 9 for Cenchrus ciliaris L Three different polyploid levels were observed, Le. tetraploid, pentaploid and hexaploid. Almosl83% of the specimens studied were tetraploid (n = 2x::; 18). 8 ~ chromosomes are present in a few of the tetraploid and hexaploid specimens. The high frequency of aneuploidy, previously desribed for th is species, has not been observed during the present study.
Keywords: Aneuploidy . 8-chromosomes, Cenchrus ciliaris chromosome numbers, polyploidy
*To whom correspondence should be addressed.
Introduction unusual for the tribe Paniceae and continued the research on The genus Cenchrus L. has been studied comprehensively, due Cenchrlls. He determined somatic chromosome numbers of 34 to some of its species' economic value as fo rage and its and 36 for C. tribuloides L. and C. pallc~florllS Benth., respec world-wide geographi c distribution. The first somatic chromo tively. Brown (1948) speculated that the loss ofa si ngle chromo some counts for thi s genus were reported by A vdulov (193 1). He some pair in Cenchrlls from 2n = 36 an d 2n = 72, could have studied three species, namely C. brownii Roem. et Schult. (previ resulted in 2n:::o 34 and 2n :::o 70. Due to this hypothesis, Cenchrlls ously known as C. inflexlts R. Br. ), C. echinatlls L. and C. myo was considered to be an aneuploid gen lls. slIroides H.B.K. (Darlington & Wylie 1955). He reported a The genus, and C. ciliaris L. in particular, are well known for somatic chromosome number of34 for C. brownii and C. echina having a wide range of discordant chromosome numbers (Table filS and 70 for C. myosuroides. I). The lowest chromosome number of the genu s, 2n = 18, has Brown ( J 948) regarded these chromosome numbers as most been reported for C. ciliaris (Mehra el al. 1968), whereas the
• •• • • ; ... • • •• -!". . -• •i ""' • .. .. • . A - B
.•. • ...... • ...... --;. It >., •• .. .'1 •
• ~ ~. ''Il .. to
c o
Figure 1 Photom icrographs indicating haploid chromosome num be rs in Cenchrus ciiiaris during anaphase I. A. Spies 5883, n = 17. B. Spies 5653. n = 18. C. Spies 5497, n = 4512. D. Spies 55/7, n = 27. Scale = ~ l m . 338 s. Air. J. BoL 1998, 64(6)
Table 1 Chromosome numbers previously reported for the different species of the genus Cenchrus /
Specie~ 2n Reference
(' bl/lorfls Roxb . 30 Miege (1962): Mehril el al. (1968); Olorooc (1975)
32 Mchru & Chaudhary (1974); Vij & Chaudhary (1 98 1): M..:hra (1982)
Dc Lisle (1963); Gupta & Yashvir (1971); Dujardin ( 1978); Vij & Chaudhary (1981): 3.1 Salmi & Bir(1985)
36 Khosla (1972); Mchra & Chaudhary (1974); Vij & Chaudhary (1981): Mehr. (1982)
C. hrownii Roem . t:l Schull. 34 A vdulov (1931); De Lisle (1963): Gould & Soder>lrom (1970)
36 Larsen ( 1963); Gou ld & Soderstrom (1970)
34- 36 Vij & Chaudhary (1981)
66 G"uld( 1966)
68 Davidsc & Pohl (1974)
C ca~rclIl{jIIlS Carom 34 Hsu ( 1972)
C ciliari.\" I.. 18 Mehra el af. (1968)
29 Spies & Du Plessis (1987<1)
Fisher el al. (1954); Nath & Swaminathan (1957); Miege (1962); Spies & Du Plessis 32 (1987b)
E.K.J. fin Darlington & Wylie (1955)1; Fi sher el al. (1954): Nai ll & Swaminathan (1957): 34 Miege (1962); De Lisle (1963); Ramaswamy et at.( 1969): Mehra (1982)
35 Krislmaswamy (1940)
Moflell & Hurcombc (194 9); Hernandez (1953); fisher e( of. ( 1954); Snyder el al. (1955); Nath & Swaminathan (1957); Dc Wet (1958 & 1960); Patil el al. (1961, published as C gloucw; Mudal iar & Sundaraj ); Micge (1962); Goult! (1968): Mchrael al. (1968); Ramaswamy el of. (1969); Malik & Tripathi (1970); Nath ell/I. (1970); Khosl a (1972): JagaIUluth & Raman (1974); Cristopher & Abraham (1976); Shamla & Sharma (1979); Rao & Mwasumbi (1981); Vij & Chaudhary (1981); Mehra (1982); Bir & Sahni (1983, 36 1984 & 1985); Bir & Singh ( 1983); Dalgaard (1986); Hihnighl el a/. ( 1991)
36 + 0-213 Vij & Chaudhary (1981)
38 Pati l el 01. (J 961, published as C. glaucua)
40 Fisher e/ al. (1954); Nalh & Swaminalhan (1957); Micge (1962)
43 Snyder el al. (1955)
Nalh & Swamillalhan (1957); Mehra et al. ( 1968); Ramaswamy el al. (1969); Nalh el 01. 44 ( 1970); lagannath & Raman (1974); Spies & Du Plessis (1986)
Palil e( 01. (1961, published as C glaucus); Shantilamma & Narayan ( 1976); Hignight e( 45 al. (1991)
48 Snyderela/. (1955)
50 Miege ( 1962)
52 Nalh & Swaminathan (1957); Nath e/ 01. ( 1970)
Hernandez (1953); Fisher el 01. (1954); Nalh & Swaminathan (1957); Miege ( 1962); 54 Ramaswamy et 01. ( 1969); Jagannath & Raman (1974); Du Pless is & Spies ( 1988)
56 Ramaswamy et a/. (1969) Jagannath & Raman (1974)
C eclWUl11IS L. 34 A vdulov (193 I); Parodi (1946); Delay ( 1947)
Nunez ( 1952); Takeoka (1955); De Lisle (1963 & 19(4); Gould (1968); Gould & Soder- 68 strom (1970 & 1974); Davidse & Pohl (1974)
C gracil/illllls Nash 34 De Lisle (1963); Davidse & I'ohl (1974)
C. incerll/,<; M .A. Curtis 32 Gould (1958)
Taleoka (1955); Gould (1958 & 1960, publ ished as C. parviceps); De Lisle (1963 & 19(4); 34 Gould (1968)
C. injlexl/J R. I3r. 34 Avdulov (193 1) s. Atr. J. Bot. 1998, 64(6) 339
Table 1 Continued
C {ongisp illlls (Huck.) Femald 34 Gould (1958): De Lisle(1963& 1964)
(. millS Andcrss 34 Dc Li sl!.! ( 1964)
C II/ ull!f/orllm Presl 34 Gould ( 1966)
C. /IIyn.I'w'v ldes II.I3.K. 54 Brown(1950& 195[)
68 Oowdt! 1l & Senn (1962)
70 t\ vdulov (1931): Parodi (1946); Gould (1968); Dc Li sle (1963 & J 9(4); Reeder (1968)
C. palme,., Vase)' 34 Dc Lisle ( 1963): Gould (1966); Reeder ( 1984)
C. pmu:ij]or(f Bcnth. 34 Tatcoka (1955)
36 Brown ( 1948) 35 Palii et (I I. (1961)
36 Khosla (1972); Oir & Singh (1983); I3ir & S 42 Singh & Godward (1960) 54 Blr & Salmi (1986): Patil et al. (1961) C pi!os//s IU3."- . 34 Dc Lis le ( 1963); Davidse & Pohl ( 19 74) C. p/alytlmllf/ms Hook. f. 34 Kliphuis ( 1977) C. prie lfrii (Kunlh ) Maire 34 Mul ay & LeeJamma (1956) Fisher eI al. (1 954); E. K.1.lin Darlington & Wylie (1955)1: Snyder ela/. (1955); De Lisle (1963); Mehra et of. ( 1968): Baquar & Anjum (1970); Malik & Tripa!hi ( 1970); Khos la r setigalls Vah l. 34 ( 1972): Vij & Chaudhary ( 198 1); Mehr. (1982); Bir & Salmi ( 1984 & 1987) Fisher el al. (J 954); Snyder et al. (1955); De Lisle (1963); Ramaswamy et af (1969); Shamlu (1970): Sinha & Jha (1972); Jagannath & Raman (1974); Christopher & Abraham ( 1976); Shanma & Shann. (1979): Sir & Salmi ( 1983); Bir & Singh ( 1983): Sir el 01. 36 (1987) 37 Patilelal.(1961} 54 Ramaswamy el al. (1969) 72 Bir & Salmi ( 1984) C IrUm/ollles L. 34 A vdulov ( 19) I); Hunter ( 1934); Parodi ( 1946); Brown ( 1948); Dc Lisle ( 1963) highest num ber, 211 = 72, is rep rese ntative of C. seligefus Vahl for speci mens of C. cilial'is representative of the main (Bir & Sahni 1984). distribution areas in South Afiica. The chromosome numbers Th e aim of this study was to determine chromosome numbers observed will be used to determine the frequency of an euploidy •, A B -----~- '. - Fi gure 2 Photomicrographs ofmeiocytes in C. ciliaris, indicating the presence ofB-chromosomes. A. Spies 5584, n = 2x = 18 + O- IB, 17- 19 distriou!ion with one chromosome undergoing chromatic segregati on during anaphase I. B. Spies 5229, n = 2x = 18 + 0-2B. 15- 19 distri hution with om: unpai red B-chromosome on the equator. C. Spies 5531 , n = 2x = 18 + 0-28, 16-18 distribution with two unpaired B-chromo somes. one on the I..:q uator and one in the pole. Scale = 10 ,.l.In . 340 S. Afr . .I . Bot. 1998. 1>4(6) of a saturated iron acetate solut ion were used as secondary mordant (Thomas 1940). Preparation s ,vere gently heated to achieve a higher con trast between the chromosomes and the cytoplasm. Finally thc~ \\ere made permanent hy freaing wi th liquid CO2 (l3owen 1956). followed by dehydration in cthnno l and mounting in Ell para l. At least 20 anaphase 1 cells per specilll t.!11 '\ ere studkd. where tilt.! rocus leve l \va s altered n:pealedly to determine tht.! exact num ber of chromosomes present . , • Results " ,- ,~ Gametic chromosome numbers, as observed during anaphase I. • 'S were determined for 76 specimens of C. c: iharis (Table 2). One • ¥."I." specimen had n = 17 (Figure IA), 63 had 11 = 18 (Figure 18), • seven had n = 45/2 (Figure Ie) and five specimens had n = 27 • .. (Figure J D) (Table 1) . ~ (t•.. B-chromosomes werc observed in II specimens with a , gametic chromosome number of n = 18, and in one specimen with a gametic chromosome number of n = 27 (Figure 2A-C) (Table 2). In anyone specimen a maximum of two B-chromo Figure 3 Geographical distribution of Cel1chrus cit/a ris in South somes were observed per cell (Figure 2C). Africa. Symbols ind icate th e variolls chromosome numbers observed, namely n = 17 (0), n = 18 (e), n = 45/2 (.) and n = 27 Discussion ( .... ). lenchrlls c;liaris is the most abundant and the most widely spread of the four Cenchrus species present in South Africa. This present in this count ry_ T hese results will be compared with species is distri buted throughout the hot dry areas, particularly those reported for the rest of the world. on sandy soils (Gibbs Russell el a/. 19(0). Its distribution pattern Materials and Methods stretches from north to south, through the middle of the country. inJ1orc!'ccnscs of C. ciliaris were collected in the main distribution This species is adapted to a very low annual rainfall , which area of Ihis species in Ihe Republic of South Afri ca. Voucher herbar makes it one of the most import ant of the pasture grasses for the ium specimens are hOllsed in Ihe Geo Polts Herharium, Department drier north-western to western areas of South Africa. of Bo tany and Genetics, University of the Free State. Bloemfontein During this study four different meioti c chromosome llumbers (BLFU), Details are given in Tab le 2. were observed for C. ciliaris. A chromosome number of n = 18 Inflorescences wl!re fixed in Ihe field. in Carnuy's fix ative (Car was the most common, observed in 82.9% of the specimens noy [886). and replaced with 70% t:thanol after 24-48 hours. The studied (Table 2). The other chromosome numbers observed material was stored at 4°C. Anth~rs were squash~d in 2% aceto-car were only at low frequencies, namely n = 17 (1.3%), 11 = 45/2 mine (13dling 1926; Darli ngton & LaCour 1976). Minul~ quantities (9.2%) and n = 27 (6.6%). The results suggest that th is species y 00,------, o Previous reports D Current results 80 70 3 60 -.----. ------,~ II 50 t------• E 40 1------E3------_.- ! ~ ~ t_------ 20t------1 ------10 - ---n ] ------x 0 n n n ~ n ,. 29 32 3< 3S 36 36+8 36 40 43 .. 45 48 50 S2 54 56 7. Previous versus current chromosome number reports Fi gure 4 Hislogrammatic comparison of chromosome numbers in Cenchrus ciliaris. S. Afr. J. Bot. 1998,64(6) 341 Table 2 List of Cenchrus cifiaris specimens studied, voucher specimen numbers and localities according to the degree reference system (Modification of Edwards & Leistner 1971) Loca lity Voucher 17 2627 (Polchefslroom): In Potchefstroom. on route to Orkney (--CA) Spies 5883 IR 2528 (Pretoria): Ncar Pn:torin (- ee) Spies 56./5 2624 (Vryburg): Nl!ar VI)'hurg. on route to Kuruman (- DC) Spies 5529 2626 (Klerksdorp): 29 km fro m Potchcfslroom to Orkney (- DD) Spies 5655 2627 (Potchcfstroom): In Potchdslroo01. no route to Orkney (-CA) .~/JteS 5653, 565.J 2628 (Johannesburg): Grassmcrc Garage, JoharUlcsburg (- AB) S'"ies 56-/6 2723 (Kununan): 16 km from Kuruman to Vryburg (-BC) Silies 5525 2724 (Taung): 101 kill rrom Kuruman to Vryburg (-AS) Spies 5527 2725 (I31oemhol): In Amalia, on route 10 Schweizer-Reincke (-AA) Spie.\' 5538, 5539 2725 (13 Ioemhot): 2 km from Britten to Chistiana (--C13) Spies 55./2, 55./] 2726 (OJenJaalsrus): 8 km from Wessel bran to Bultlonh!in (- CD) ,\jJie.l'5659 46 kill from Bothaville to Wesselbron (- DA) Sple.~ 565 7 2727 (Kroollslad): 6 I kill from Kroonstad to Pal),s (- AC) ~pies 5650 7 kill from Kroonslad to Kroonvaal (- CA) Spies 56./9 2732 (Ubombo): Mhlosmga, on route to Sordwana (--Ce) "enter 9286 2822 (Gl en Lyon) : 7 km from Smidtsdrill to Poslmasburg(- DA) Spies 5521, 5522 2825 (Bosho!): 50 kill from Hertzogville to Bultfontein (- B8) Spies 5553 2826 (Brandtort): 57 km from Wesselbron to Bultfontein (- AA) Spies 5662 30 km from Wcssclbron to Bultfontein (-I3B) Spies 5660 25 kill from Bloemfontein to Bmndtort (--CD) Spies 5576, 5577 27 km Irom Blocmfontein to Brandfort (--CD) Spies 5574, 5575 38 km Irom Bloemfontein 10 Brandfort (-CD) Spies 58./9, 5S5() 32 km Irom 13I0cmtoniein to Ahrahamskraal (--CD) Spies 5638 2925 (Jagersfonlein): 56 km from Pelrusburg to Kimberley (- AA) Spies 55(}9 44 kill from Pdrusburg 10 Kim berley (- All) Spies 55()8 2926 (Bloemfontein): Ncar i31ocmfonlcin (- AA) Spies 56./3, 566-1 62 km from Pctrusburg to I3loemfontein (- AA) Spies 5642 f6 kill from Bloem fontcin to Wi nburg (- AA) Spies 5847 3 125 (S teynsburg): 30 km Irom Sleynsburg to Hofmeyer (- BC) :'ipies 5668, 5669 ncar Hofmeyer (-DC) Spies 5587 12 kOi from Ho flneyer to Cradock (- DC) Spies 5670 30 km from Hofmeyer to Crado.:k (- DC) !':,jJies 5671 3222 (Beaufort West): 5 km from l3eautort West Spies 5./87, 5./89 3224 (GraafT-ReincL): 58 km from lansenvillc 10 Graatf-Rein cL (-BC) Spies 52.1n 13 1 km from Uitenhage to GraafT-Reinet (- DC) Spies 523(i 145 km from lJitenhage to GraalY-Reinet (- DC) Spies 5237 122 km from Patensie to Willowmore (- DO) Spies 5215 3225 (Somerset East) : 57 km from Cradock to Cookhouse (- DB) Spies 5591 KokskraaL Cookhouse (-DB) Spies 559-1,5676 3320 (Ladism ilh): 4 km fro m CalitZllorp to Oudtshoom via Kuilsrivicr (- DC) Spies 5226 3324 (Stcytlcrville): 102 km from Uilcnhagc to Graaff-Rcinct (-BO) Spies 5232 3325 (Port Elizabeth): 40 km from Uilenhage to Grauff-Reinet (-CD) Spies 5230 18 :: 0-2B 2624 (Vryburg): Near Vryburg, on roule to Kuruman (- DC) Spies 5531 2627 (Polchefstroom): 10 k.ln from Parys to Polchefstroolll (-CD) !':,jJie,\' 5652 2925 (Jagersfontein): 60 km from Petrusburg Lo Kimberlcy (- AA) ~pies 5512 342 S. Mc. J. Bot. 1998.64(6) Table 2 Conlinued 2926 (Dlocmrontein): 25 km Irom Bloemfonte in to Winburg (-AA) Splt!S 58./8 3125 (Steynshurg ): 10 kill from Stt:ynsburg (0 ' iofnll.::yer (- Be) ~/J/· e.\· 558./, 5585 24 km Irom SlcYllsburg to lIa/meyer (-Ge) Spies 5586 3222 (Bc 3225 (Somerset East): Kni 3324 (StcYllcrvi ll): 6& kill Irom lJitcnhage to Graaff-Rcinct (- DA) '~/]J'eJ 5231 3325 (Port Elizaheth): 30 k111 from Uitcnhage to Graarr·Rl.':inct (-CD) S/Jies 5229 45 /2 2522 (Sanie): In the ri w rhcd at Watcrsend (- DO) Spies 5./9 7 2925 (Jagcrstontcin ): Spitskop fam1 yard, Faurcslllith (- 01\) DII Pree= 2758 3024 (Colesburg): 27 km from Vcrwocrddam to Ventcrslad (- DA) Spies 5581. 5583 3224 (GrnaIT-Reinet): 3<) krn from Janscllville 1('1 GraalT-Rcinct (- DA) Spies 5239 15 krn from JansenviJlc to GraalT.. Reinel (-DC) .~/)i es 5238 76 kill from Palcnsic 10 Willowmore (-DO) Spies 521n 27 2824 (Kimbt:rley): I klll from Kimberley to Griekwaslad (- OA) Spil:!s 5513, 55/{ 5515 2925 (Jagcrsfonlcin): 4-1 km Irom PClrusburg to Kimberley .\'pies 55 J() 27 + 0-18 2824 (Kimberley): 1 kill from Kimberley to Griekwastad (- DA) .\))ies 55! 7 has a basic chromosome number of x = 9, since 9 is the largest were di stributed th roughout th e species' main di stributi on area, common denominator fo r 98.68% of all the specimens studied but the hexaploids were all coll ected in the vicinity of Kim berley (all specimens excl uding n = 17). This suggesti on is supported (Figure 3). The single specimen with n = 17 was collected at the by an earlier chromosome num ber report of2 11 = 18 fo r this spe premi ses ofa plant breeding company. It formed part ofa breed cies (Table I). ing programme of C. c;i1iaris and it is thus no t representative of With a basic chromosome number of x = 9, three polyploid th e wild specimens of that particular area (Figure 3). The low levels are present in C. ciliar;s. namely tetra-, penta- and hexa percentage of aneuploidy contrasts with all previous reports that ploidy, as well as 1.3% aneuploid specimens (n = 17). The th is species is a highly aneuploid species. geographical distribution of the chromosome numbers observed Published chromosome numbers for C ciliar;s include 2n = is plotted ill Figure 3. The tetrapl oi d tlild pcnt aploid specimens 18 (1.3%), 29 (1.3%),32 (5. 1%) , 34 ( I 1.4%),35 (1.3%),36 S. Mr. J. Bot. 1998, 64(6) 343 y 60 .54 .54 .54 50 - 48 :~ 44 .43 40 .40 .!• x36 x 36 x 36 x 36 x 36 x 36 x36 E •r 4"032 032 •E 30 .2. .20=29 ~ 0 02n :::32 E e ... 2n=34 u~ )(2n=36 20 . 2n : 40 e2n=43 a2n '" 44 - 2n =48 ' 0 -2n=52 0 2n= 54 _ 2n =56 X 0 '9<' 1953 1954 1955 1958 1960 '986 1987 1988 1991 YUB during which the various chromosome numbers have been reported Figure 6 Rang!.! or chromosome! numhers observed in (. cJ!wr/s in SouLh Africa during the period 1949- 199 1. (35.4%), 36 + 0- 2B ( 1.3%), 38 ( 1.3%),40 (5.1 %), 43 ( 1.3%), 44 (Nash & Swami nathan 1957), 2n = 18, 36, 44 (Mehra el al. (8.9%), 45 (2.5%), 48 (1.3%), 50 ( 1.3%), 52 (5.1 %),54 ( 11.4%), 1968), 2n = 34,36, 44, 54, 56 (Ramaswamy el al. 1969), 2n = 36, 56 (5.1 %) and 78 (1.3%) (Figure 4 and Table I). The percentages 44,52 (Nath el al. 1970), 2n = 36 (Christopher & Abraham 1976 ; in parenthesi s are based on the number of references to that par Sharma & Sharma 1979), 2n = 36, 36 + 0- 2B (V ij & Chaudhary ticular chromosome number as reported in the literature. The 1981), 2n = 34, 36 (Mehra 1982) and 2n = 36 (Bir & Singh, 1110st abundant chromosome number recorded previously is 36 1983;Bir & Sahni, 1983, 1984, 1985). . (3 5.4%), fo ll owed by 34 and 54, which are equally well repre The earlier period (1940- 1970) incl uded a wi de range ofchro sented in the literature (I 1.4%), and 44 (S.9%), mosome numbers, with a lowest nu mber of2n = 18 and a highest The current results partly concur with those previously of 2n = 56, whereas mostly 2n = 36 has been observed for th e reported, since 2n = 36 is also the most abundant chromosome later peri od, 1976- 1985 (Figure 5). The fact that most,of th e nu mber presently observed (Figure 4). The main differen ce 'aneuploid ' chromosome numbers were determined during the between the two sets of chromosome numbers (current versus Iit earlier period and included many numbers uncommon for th e erature) is th e freq uencies at which they have been observed, Paniceae, renders their accuracy doubtful. namely 211 = 34 (1.3% versus 11.4%), 36 (82.9% versus 35 .4%), Chromosome number reports for South Africa include the fol 45 (9.2% versus 2.5%) and 54 (6.6% versus 11.4%). lowi ng: 2n = 36 (Moffett & Hurcombe 1949), 2n = 36, 54 The differences between the current results and those in the lit (Hemandez 1953), 2n = 32, 34, 36, 40, 54 (F isher el al. 1954), 2n erature, regarding the freq uencies of reports of 2n = 34 and 2n = = 36, 43, 48 (Snyder el al. 1955), 2n = 36 (De Wet 1958, 1960), 36, can be due to vari ous facto rs. A major possiblily is that in the 2n = 44 (Spies & du Pless is 1986), 2n = 29, 32 (Spies & du past chromosome numbers were incorrectly reported, due to the Plessis 1987a & b), 2n = 54 (Du Plessis & Spies 1988) and 2n = extremely smai1 size of this species' chromosomes. The number 36 (Higni ght el al. 1991). of chromosomes participating in con fi gurations during diakinesis The situation for South A fr ica (F igu re 6) is markedly different are thus extremely di fficult to determine. from that in India (Figure 5) . Not only was a wide range of Therefore. chromosome numbers for C. ciliaris should be aneuploid and euploid chromosome numbers reported by the determined onl y from ideally spread anaphase I cells (Figure I earli er workers (1949-1955), but these reports were verified by A-D). later investigalion s (1 986- 1991) (Figure 6 and Table I). Since the aim of most of th e reports published earli er was pri Vari ous authors have confirmed that C. ciliaris has a hi ghly marily to determine a chromosome number for some of the spe polymorphic nature (Nash & Swanunathan 1957; De Lisle 1963; cies only, a limited number of cells and specimens may have Rameswamy el al. 1969; Nath el al. 1970; Vij & Chaudhary been studied . 198 1; Hi gnight el al. 1991), reflective by high genetic vari abili ty Chromosome numbers may, therefore, have been based on the and variolls polyploid levels. minimum cytogenetic results. In conj unction with this, reports The occurrence of 11 specimens with B-chromosomes is unex published by many of the earlier workers did not mention herbar pectedly high, as they have been observed only once before in ium vouchers (De Lisle 1963). For thi s reason, it is not always C ciliaris (Vij & Chaudhary 1981). These additional chromo possibl e to attest to the vali dity of the counts. somes were observed mostly in the tetraploids (Table 2) and Chromosome num ber reports from India include the follow were identified only in ideally-spread anaphase I cells. ing: 2n = 35 (Krishnaswamy 1940), 2n = 32, 34,36, 40, 52, 54 The presence of B-chromosomes in thi s species may partially 344 S. i\1f. J. Bot. 199s' 64(6) explain the wide range of chromosome numbers reported in the CARNOY. J.13. 1886. La c)ll)(Jiercsc de J'ol!uf Cellule 3: 1- 92. past. B-chroJl1oso mcs and euchromosomes in C. ciliari... arc CHRISTO PHER. J. &. A BRAIIAM. A. 1976. Studies on the C}lll log} mostly of eq ual size. This, in turn, could lead to the misinterpre llnd phylogeny of SOllih Indian Grasses Il l. Subfamil) VI : Pani tation of th e euchromosome complement and can also contribute coideae. tribe Paniceae. (l'lo!ogw 43: 273- 287. to the difference in aneuploid and polyploid percentages I)ALGAA RD. V. 1986. Chromosome numbers in tlowering planls from observed during the present study, as compared to those reported Madeira. Wiildenow;a 16: 221 - 240. [)ARl.lNGTON. CD. & WYLIE. A.P. 1955. Chromosome Alia.... of previously. Flowering Plants. Allen and Unwin, London. DAR LI NGTON. CO. & LACOUR. L F. 1<)7(). The handling of chro Conclusions mosomes. Allen and Unwin. London. Four chromosome numbers have been observed for C. ciliaris DAVIDSE. G. & ]>OHI.. R.W. 1974. Chromosome numbers, lllCIOlic during the present study, of which n = 18 was the l11os1 common chromosome behavior. and noti..'s on lropical American grasses number observed. No co rrelation existed between the chromo (Gral1lineae). emwd. 1. BOl. 52: 3 17-328. some number of a specimen and its geographical distribution, DELAY. C. 1947. Recherches sur la structure des noyaux quicst.:cnts except for the hexaploid specimens (n = 27) which were chc/. les phancrogames. Rei· (~\'lol. Cywph.niol 9: 169-222. restricted to one small region ol1ly. It is suggested that hybridiza DE LISLE. D.G. 1963 . T <.l.XOnolllY and distrihution of the gelllls Cell tion among and within populations may play an important role in ehrus.lowa Stale 1. Sci. 37: 259-351 . the establishment of genetic variation in this species. Dr LISLE. D.G. 1964. Chromosome numbers in eellchrll.\· The result s establish a basic chromosome number ofx = 9 fo r «(jramincae). Amer.J. BOI. 5 1: 1133- 1135. r. ciliaris and indicate three polyploid levels and 1.3% aneup DE WET. J.M .J . 1958. Additioll 21l,2 11- 275. REEDER, J.R. 1968. Systemalic position of the Genus Tr/JI/Ochfoa MALIK. c.P. & TRIPATHI, R. C. 1970. In lorn Chromosome numher (Gramineae). Amer. J. Hot. 55: 735. reports. XXVII. Taxon 19: 437-442. REEDER, J.R 1984. In lorn chromosome nwnhl!r reports. l.XXXII. MEHRA. P.N 1982. Cytology of East Indian g.rasses. II.N. Mehra. Taxo1l33: 126- 134. Chandigarh . 5AHNI, M. & BIR. 5.S. 1985. SOClil planl chrOmOSO lll l! number MEHRA. !l.N. & CHA UD HARY . J.D. 1974. In IOPB chromosome reports·lIl. 1. (Vlo/. Genet. 20: 205- 206. numht:r reports. XL VI. Taxon 23: 801 - 8 I 2. SHANTHAMMA, C. & NARAYAN. K.N. 1976. In rOPB chromosome MEHRA. r.N .. KHOSLA. P.K.. KOHLI, B.L. & KOONER, 1.S . 1968. Cytological Studies in the North-Indian Grasses (Part I). Res. Bull. number reports. L1. Taxon 25: 155- 164. ?cmjah Ulliv. 19: 157- 23 0. SHARMA, M.L. 1970. Annual rl!pnrt. 1967-1968. Res. Hull. UII/\, . Cal· MIEGE. J. [962. Quatrieme lisle de nombers chromosomiq ul!s d'cspe culla 2: I- 50. ces d'Afriquc Occidentale. Rev. (vIol. et BioI. veg. 24 : 149- 164. SHARMA, M.L. & SHARMA A. 1979. Some considl!rations on the MOFFETI'. A.A & I-IURCOMBE. R. 1949. Chromosome numbers of phylogeny and chromosomal evolulion in grasses. Cywlogia 4-l : 679- South Afri can grasses. Heredity 3: 369-373. 685. MUI.AY. B.N. & LEELAMMA, P.J. 1956. Chromosome numbers of SINGH, D.N. & GODWARD, M.B. E. 1960. Cytological studies in the some desert grasses. Proc. Rajasthan Acad Sci, 6: 65-69, Gramineac. Heredity 15: 193- 19 9. NATH. J. & SWAMINATHAN. M.S. 1957. Chromosome number of SINHA, R.R.P. & JHA, R.P. 1972. Cytological stud ies in sOll1 e gra.'ises somt.! grasst.!s. II/dian 1. Genet. PI. Breed. 17: 102. of Bihar. Proe. Indian Sci. COl/gr. A.\"Joe. 59: 352- 353. NA TH , J.. SWAM INATHAN , M.S. & MEHRA, KL. 1970. Cytological & 1955. studies in Tribe Panict.!ae. Cyt%gio 35: 111 - 131. SNYDER, L.A., HERN ANDEZ, A.R. WARMK E, H.E. The NUNEZ. O. 1952. rnvertigaciom.::s cariosistematicas en las Gramineas mechanism of apomixis in Pellnisetlllll ciliare. Bot. Co:::. 11 6: 209- Arg.enlinas de 1a tribus ' Paniceae'. Rev. 1. 0 Plata Uni\'. Nac. Fae de 221. Agroll. 2R: 229- 256. SPIES. JJ. & DU PLESSIS. H. 1986. Chromosoml! studies on Afri can OLORODE. O. 1975. Additional chromosollll! counts in Nigeri an planls. 2. BOlhalia 16: 269-27 1. grasst.!s. Hrillollia 27: 63-68. SPIES. 1.J . & DU PLE SS IS, H. 1987. ChromosOlm: studies on African PARODI. L.R 194 6. Grmnineas boncrenses crave pare la dctemlinecion plants. 5. Boillalia 17: 13 1- 138. de los gencros Y cllumerocion dl! las cspecies. Univ. Buenos Aires, SPIES, J.J. & DU PLES SIS. H. 1987b. Chromosome studies on Ali-iean Buenos Aires. plants. 3. Bo/halfa 17: 257- 259. I'ATIL. 8.0 .. VOHRA, S.K. & JO SHI. A.B. 1961. Chromosome num TATEOKA, T. 1955. KaryotaxonolllY in Poaecae. ill. further studies of bers in some tbrage grasses. Currem Science 27: 140-141. RAMASWAM Y, K.R .. RAMA N, V.S. & MENON, P.M. 1969. An somatic chromosomcs. CYIOJogia 20: 296--306. analysis or morphological variation in relation to chromosomal lonm THOMAS, P.T. 1940. The aceto-carmine method lor Iruit material. in Cellchrus complex. 1. Indian Bot. Soc. 48: 102- 111. Stain Techno/. 15: 167- 172. RAO, !'.N. & MWASUMBT, L.R 1981. In Ch romosome number VIJ, S.P. & CHAUDHARY, J.D. 1981. Cylological investigation in reports. LXX. Ta.ton 30: 79-80. three species of Cenehrus L. (Gramineae). ( vtologia 46: 661-669.