Phenotypic diversity in sorghum [Sorghum bicolor (l.) Moench] landraces in Tigray, northern Ethiopia

Abstract In the present study, frequency distribution, Shannon–Weaver diversity index (H′), and multivariate methods were used to estimate and analyze the phenotypic diversity of 108 sorghum landraces growing in Tigray taking their districts of origin, geographical zones, and altitude classes into considerations. We discover that high and comparable trait distributions among the sorghum landraces. The H′ computed for individual traits varied from 0.33 for grain form to 0.99 for grain plumpness with a mean of 0.83, which reveals huge diversity within the landraces. The estimated H′ of each trait pooled over districts of origin, geographical zones, and altitude classes were high with an overall mean of 0.71, 0.74, and 0.70, respectively. The H′ pooled over traits within the districts of origin, geographical zones, and altitude classes were high with an overall mean of 0.71, 0.74, and 0.69, respectively. On the basis of district origin, the highest (0.84) and the lowest (0.46) H′ values were recorded for the Tahtay adyabo and Raya Azebo districts, respectively. When the geographical zones were considered, the highest (0.83) and the lowest (0.46) H′ values were recorded for the northwestern zone and southern zone, respectively. With respect to altitude classes, the highest (0.80) and the lowest (0.68) H′ value were recorded for 1001 m.a.s.l and > 1600 m.a.s.l, respectively. Disruptive selection is the most likely reason to maintain the huge diversity in the sorghum landraces. The treasure of diversity suggests the potential for exploitation in sorghum improvement and conservation programs.