Components Analysis of Yield Responses to Drought of Sorghum Hybrids

Abstract

Drought resistance in terms of yield and its components was studied in the field in twenty-one agronomically-adapted high-performance grain sorghum (Sorghum bicolorMoench) hybrids. Resistance was considered to be indicated by a minimal decrease in yield under stress as compared with non-stress conditions. Water stress, imposed by a decreasing amount of stored soil moisture during the growing season, decreased grain yield and number of panicles per unit area, increased the number of grains per panicle, the number of branches per whorl and the number of grains per branch, and decreased the number of whorls per panicle. Thus a compensatory effect was observed in some components for reduction in tillering under stress. Resistant hybrids performed better than susceptible ones under stress by producing a relatively higher number of panicles per unit area, and more grains per panicle branch. Susceptible hybrids performed better than resistant ones under non-stress (irrigated) conditions due to the relatively higher number of panicles per unit area and larger 1000-grain weight. Some of the implications regarding selection for yield performance under drought are discussed.