Genome analysis of Eleusine coracana (L.) Gaertn

Abstract

Two sets of interspecific hybrids E. coracana x E. africana and E. coracana x E. indica were produced. The hybrids were intermediate between the parent species for most of the matrical characters observed. The dominance-recessive relationships of various qualitative characters were studied in the hybrids. Meiotic behaviour was normal in the parent species. Regular 18 bivalents were observed in E. coracana, E. africana and invariably 9 bivalents were noticed in E. indica. In an E. coracana x E. africanahybrid mean chromosome pairing of 0.004 I + 17.71 11 + 0.06 III + 0.08 IV per cell was found. About 87% of the cells showed regular 18 bivalent formation. Preponderance of bivalent formation in the hybrid strongly suggests that the genomes of E. coracana and E. africana are basically similar and E. coracana might have originated as a result of selection and further cultivation of a large grain mutant from E. africana. The genomic notation of AABB has been proposed for these two species. From meiotic analysis it is obvious that E. africana is an allotetraploid and must have originated as a result of hybridization between two diploid taxa followed by chromosome doubling. In triploid E. coracanax E. indica hybrid 99.5 % of the cells contained 27 univalents and 0.5 % of the cells showed a single bivalent and 25 univalents. This pairing behaviour indicates that E. indica may not be A or B genome donor to this millet.

Mapping of rDNA on the chromosomes of Eleusine species by fluorescence in situ hybridization.

“…Basically the genus Eleusine has only seven to eight well defined species and grows in the field. The polyploid species E. compressa is now excluded from Eleusine and included in the genus Ochthochloa as O. compressa (Hilu, 1981) and another polyploid species E. reniformis defined as a species by Divakaran (1959Divakaran ( , 1962) is now merged with E. coracana (Chennaveeraiah and Hiremath 1974). The genus now includes three polyploid species and four to six diploid species.…”

“…E. indica is a cosmopolitan species distributed in tropical to temperate parts, whereas E. tristachya is native of South America and adventive in various parts of the Old World, Australia and North America (Hilu, 1980;Phillips, 1972). E. coracana, a tetraploid, is only species of the genus which is economically important and cultivated for its grain in many countries of Africa and Indian subcontinent (Chennaveeraiah and Hiremath, 1974;Hilu and deWet, 1976). The infrageneric classification of this small genus always remained controversial and species like E. compressa and E. multiflora kept shifting from one genus to another (Hilu, 1981).…”

“…The infrageneric classification of this small genus always remained controversial and species like E. compressa and E. multiflora kept shifting from one genus to another (Hilu, 1981). Genome donors to various polyploid species also, more or less, remained unknown, despite various cytogenetical and molecular investigations (Chennaveeraiah and Hiremath, 1974;Hilu and deWet, 1976;Hilu, 1988;Hiremath and Salimath, 1992;Salimath et al, 1995).…”

Cytogenetical Studies in Wild and Cultivated Species ofEleusine(Gramineae)

“…Earlier studies were concerned largely with obtaining chromosome counts ( Table 1 ). However, CHENNAVEERAIAH and HIREMATH (1973), n == 9, 2n == 18.…”

“…SINGH and GODWARD (1960), CHENNAVEERAIAH and HIREMATH (1973), n == 9, 2n = 18. REEDER (1968), 2n == 16.…”