EVIDENCE FROM RAPD MARKERS IN THE EVOLUTION OF ECHINOCHLOA-MILLETS (POACEAE)

Echinochloa (Poaceae) includes two domesticated species, Echinochloa utilis (Japanese barnyard millet) and E. frumentacea (Indian sawa millet) and 20-30 wild species. The two millets are morphologically very variable and overlap in spikelet and inflorescence characteristics. Both species are hexaploids based on x = 9. Cytogenetic studies point to the hexaploid wild species E. crusgalli and E. colona as possible progenitors of E. utilis and E. frumentacea, respectively. The tetraploid E. oryzoides is considered as a possible genome donor to wild and domesticated barnyard millet. Markers from Random Amplified Polymorphic DNA method were used to assess the proposed phylogeny and examine the genetic diversity in both domesticated and wild species. The data were analyzed numerically. Echinochloa utilis and E. frumentacea appear very distinct, but grouped with E. crusgalli and E. colona, respectively. The tetraploid E. oryzoides show strong genetic affinity to the E. utilis - E. crusgalli group. The data are in general agreement with the cytogenetic information; however, some disagreements on the interpretation of some of the cytogenetic information is raised. The variability in DNA markers observed in the domesticated species, particularly E. frumentacea, points to the feasibility of using RAPD markers in cultivar fingerprinting and breeding programs of these millets.