Genetic Variation Between Ecotypic Populations Of Chloris Roxbhurghiana Grass Detected Through Rapd Analysis.
Mnene, W. Ngoyawu
Mweki, N P.
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Chloris roxburghiana is an important rangeland grass in Kenya. In some areas it has disappeared due to land degradation resulting from overgrazing and drought. Efforts to re-introduce the grass through re-seeding using seeds from research stations have had little success. One possible reason for low establishment is attributed to transplanting since spatially separated populations may represent genetically distinct ecotypes. To test this hypothesis, germplasm diversity within and among four populations of C. roxburghiana from four ecologically distinct sites was analyzed using random amplified polymorphic DNA (RAPD) markers. A total of 131 polymorphic markers were identified using nine RAPD primers. There was significant variation among populations with genetic diversity (He) ranging from 0.142 to 0.193. Twenty four percent of the variation observed was due to differentiation among the populations, compared to 76 percent accounted for by variation within populations. The UPGMA of the population frequency indicated that the four populations of C. roxburghiana were genetically distinct, probably as a result of variation in soil fertility, geographical isolation and socio-ecological history of the study sites. The implication for optimizing future seed collection is discussed and potential areas for further studies identified.