GENOTYPE BY ENVIRONMENT INTERACTION AND YIELD STABILITY OF EARLY MATURING SORGHUM [Sorghum bicolor (L.) Moench] VARIETIES IN EASTERN AMHARA, ETHIOPIA

Abstract

Sorghum is a drought and heat-tolerant C4 tropical crop with wide agro-ecological adaptation. Twenty early maturing sorghum varieties were evaluated at five locations using randomized complete block design with the objectives of estimating the magnitude of genotype by environment interaction for agronomic performance and to assess grain yield stability in eastern Amhara region. A mixed model with fixed genotypes and random environments were used for combined analysis of variance. Combined analysis of grain yield revealed highly significant difference (P 0.01) between genotypes, environments and genotype by environment interaction. Melkam was found to be the highest yielding genotype followed by Meko-1, ESH-1 and ESH-3 with mean grain yields of 3.72, 3.37, 3.13 and 2.93 t/ha, respectively. Seven stability measures such as GGE biplot, 􀝌􀝅, 􀜾􀝅, 􀜵􀬶􀝀􀝅, 􀝓􀝅, 􀝏􀯜 􀬵, 􀝏􀯜 􀬶 , 􀝎􀯜 􀬶, ASV were used to identify stable genotypes with consistent yield performance across the testing environments. Spearman’s rank correlation was used to see the level of association among these stability measures. Cultivar superiority measure showed a highly significant negative rank correlation (r = -0.973) with mean grain yield. However it did not show any correlation with other stability measures. Coefficient of determination showed highly significant negative rank correlation with 􀜹􀝅, 􀜵􀬶􀝀􀝅 and ASV (r=-0.92, -0.869, -0.851, respectively). ASV showed highly significant positive correlation with 􀜵􀬶􀝀􀝅 􀜽􀝊􀝀 􀜹􀝅 (r=0.886 and 0.812, respectively). AMMI model selected best genotypes that suit specific environments. Accordingly; genotypes G10, G12, G7 and G6 were selected as best genotypes for Kobo; G6, G7, G14 and G15 for Sirinka; G6, G14, G15 and G5 for Jarri; G5, G14, G3 and G15 for Chefa; G6, G7, G13 and G4 for Shewarobit. Chefa and Shewarobit were the most responsive (high yielder) environments. Among the 20 genotypes, G6, G14 and G7 were stable by most of stability parameters coupled with high yield. Since the experiment was done in one year at five locations, it has to be repeated in multi locations to generate more reliable results to identifying the stable genotypes for wider production and to recommend specifically adapted genotypes for specific environment