EVOLUTION OF FINGER MILLET - EVIDENCE FROM RANDOM AMPLIFIED POLYMORPHIC DNA

Finger millet (Eleusine coracana ssp. coracana) is an annual tetraploi d member of a predominantly African genus. The crop is believed to hav e been domesticated from the tetraploid E. coracana ssp. africana. Cyt ogenetic and isozyme data paint to the allopolyploid nature of the spe cies and molecular information has shown E. indica to be one of the ge nomic donors. A recent isozyme study questioned the proposed phylogene tic relationship between finger millet and its direct ancestor subspec ies africana. An approach using random amplified polymorphic DNA (RAPD ) was employed in this study to examine genetic diversity and to evalu ate hypotheses concerning the evolution of domesticated and wild annua l species of Eleusine. Unlike previous molecular approaches, the RAPD study revealed genetic diversity in the crop. The pattern of genetic v ariation was loosely correlated to geographic distribution. The allote traploid nature of the crop was confirmed and molecular markers that c an possibly identify the other genomic donor were proposed. Genotypes of subspecies africana did not group closely with those of the crop bu t showed higher affinities to E. indica, reflecting the pattern of sim ilarity revealed by the isozyme study. The multiple origin of subspeci es africana could explain the discrepancy between the isozyme-RAPD evi dence and previous information. The RAPD study showed the close geneti c affinity of E. tristachya to the E. coracana - E. indica group and u nderscored the distinctness of E. multiflora.