Genotype x environment interaction on sesame (Sesamum indicum L.) seed yield

Abstract

Sesame is an oilseed crop grown for its seed and oil for local and export markets and is a great source of income for farmers, traders, processers and the national economy of Ethiopia. However, its productivity and production are influenced by environmental factors. This experiment was, therefore, carried out to estimate the nature and magnitude of interaction of genotypes with the environment and to identify stable sesame genotypes in Eastern Amhara Region. Twelve sesame genotypes were studied at eight environments: namely: Chefa, Kobo and Shewarobit in 2010 and 2011; Jari and Sirinka in 2011 main cropping seasons using randomized complete block design with three replications. Data were analyzed for individual location and across locations using GenStat, and stability using Agrobase softwares. The highest seed yields were obtained from genotypes Acc.00047, NN-0143 and Acc.202-344 (712.8, 679.2 and 639.9 kg ha-1), respectively. There were highly significant difference (P<0.01) among genotypes, environments and Genotype by Environment Interaction (GEI), indicating that genotypes performed differently across locations and the need for stability analysis. Based on stability models, genotype Borkena was stable genotype, but genotype Acc.00047 had specific adaptability at potential environment (Kobo). In Additive Main effect and Multiplicative Interaction (AMMI) analysis, the proportion of variance captured by environment 51.2%, genotypes 12.9% and GEI 31.9% of the total variation. The Interaction Principal Component Axis 1&2 (IPCA1&2) of AMMI model were highly significant (P<0.01) and captured the largest portion of variation (74.7%) from the total GEI, indicated that the AMMI model 1 was the best for the data evaluate. AMMI 1 biplot graph showed that Shewarobit and Kobo were potential and favorable environments; Sirinka was an average, while Chefa and Jari were unfavorable environments for sesame production and also Shewarobit and Chefa were the most discriminating environments, while local variety and genotype Acc.00047 were the most responsive genotypes.   Key words: Additive Main Multiplicative Interaction (AMMI), location, specific adaptation, stability, wide adaptation.