ANALYSIS OF REGIONAL PATTERNS OF PHENOTYPIC DIVERSITY IN THE ETHIOPIAN TETRAPLOID AND HEXAPLOID WHEATS

Tetraploid populations (153) and 72 populations of hexaploid wheats collected in Ethiopia from 20 and 17 regions, respectively, were grown in a greenhouse, and 6331 and 2700 individuals of tetraploids and hexaploids were studied for basal spikelet fertility, awn color, glume color, glume hairiness, kernel color, kernel weight, number of tillers, plant height, spike length, number of spikelets per spike, and number of seeds per spike. Analyses of regional patterns of character variation to determine the relative contribution of various regions to germplasm resources showed differences in the level of importance of useful germplasm material. Polymorphism of characters studied is higher in tetraploids. The contribution to the total variation varies among characters. In both tetraploids and hexaploids the contribution to the total phenotypic diversity is highest at the lowest level (within localities), followed by the differences among populations in a region, and among regions. Both tetraploids and hexaploids are assumed to equally rely on phenotypic plasticity in adapating to the multiplicity of environments, and Twinspan analysis showed differences in the frequencies of characters preferring negative and positive groups differentially among the various regions. Combinations of characters showed dissimilarity among regions and between ploidy levels. This may mean particular adaptive strategies through the effect of correlated characters.