GENOTYPES X ENVIRONMENT INTERACTION AND STABILITY OF BLACK CUMIN (Nigella sativa L.) GENOTYPES FOR SEED YIELD AND YIELD RELATED TRAITS IN EAST SHOA AND WEST ARSI ZONES

Genotype by environment interaction and yield stability analysis are important in measuring varietal stability and suitability for cultivation across seasons and different ecological zones. The genetic potential contained within the crop, the environmental effects and their interaction play a great role in determining the yield performance and stability of the crop to a given environment. Such kind of study was lucking at the study areas and the current study was conducted with the objectives of assessing the magnitude of environments, genotypes and genotype by environment interaction effects, assessing the stability and adaptability of genotypes under different agro-ecological conditions and testing the degree of association among the stability measuring parameters. The experiment was conducted in East Shoa and West Arsi zones at six locations during 2018/19 cropping seasons. Fifteen black cumin genotypes were grown and the experiment was laid down in randomized complete block design. Combined analysis of variance for seed yield had showed highly significant difference among genotypes, environments and genotype by environment interaction. This indicated that a particular genotype might not exhibit the same phenotypic performance under different environmental conditions or different genotypes might respond differently to a specific environment. Variety Gammachis was found to have the highest (1.350 tons ha-1) mean seed yield followed by Dirshaye, Soressa, with their respective mean seed yield of 1.256 tons ha-1and 1.208 tons ha-1.The most important stability measuring parameters were concerned with to identify the stable genotypes with consistent yielding performance across the test environments. Genotypes such as Dirshaye, Soressa and AC-BC-10 were the most stable genotypes by most of stability measuring parameters. AMMI model selected the best genotypes that suit to a specific environment. Accordingly, varieties Gammachis, Dirshaye, Soressa, Derbera and Eden were selected as best varieties at ATARC and Bekele Girrisa; Gammachis and Dirshaye at Ali Woyyo; Derbera and Dirshaye at Makko Oda; Gammachis and Soressa at Bute; and Gammachis, Dirshaye, Soressa and Derbera at Umbure. The result of spearman’s rank correlation coefficient revealed that seed yield showed a highl