Patterns of morphological variation of sorghum (Sorghum bicolor (L.) Moench) landraces in qualitative characters in North Shewa and South Welo, Ethiopia

Thirty‐four sorghum (S. bicolor (L.) Moench) landraces consisting of 1020 individual plants (30 plants of each landrace) collected from five agroecological sites (ecosites) in North Shewa and South Welo regions of Ethiopia (Bati 8, Fontenina 5, Haik 2, Layignaw ataye 17 and Merewa Adere 2) were classified on the basis of 4 classifying variables: administrational zones; Woredas (smallest administrative unit), ecosite of origin and altitude. Morphological variation for the fourteen qualitative characters that showed two or more phenotypic classes were estimated using the Shanon–Weaver diversity index (H′). Phenotypic variation was found between and within each classifying variables. The value of H′ for all landraces varied from 0.32 to 0.98 with an overall mean of 0.77±0.04. One‐way analysis of variance (ANOVA) showed significant differences between characters within all classifying variables and this contributed to the largest portion of the total variance. Cluster analysis based on ordinal variables grouped the landraces into five clusters. A higher proportion of landraces sharing similar altitude classes and similar ecosites were grouped together. Panicle compactness and shape as well as stalk juiciness were the predominant characters in grouping the landraces into their respective clusters. Panicle compactness and shape also contributed relatively more to altitudinal and ecological differentiation. This differential distribution of landraces with panicle types with respect to compactness and shape revealed the adaptive significance of panicle compactness and shape that reflected the patterns of distribution of different races in north Shewa and south Welo. χ2 test of all characters did not show significant differences between the frequencies of observed and expected characters.