Genotype by Environment Interaction and Stability Analysis of Tef (Eragrostis tef (Zucc.) Trotter) Varieties for Yield and Yield Related Traits in South and South Western Ethiopia

Abstract

Tef is the most important staple cereal crop in Ethiopia. However, its productivity is low due to several biotic and abiotic constraints. The diverse and dynamic environmental condition of Ethiopia needs detailed and sustainable study of genotype by environment interaction (GEI) for developed tef varieties. The objective of this study was to evaluate the genotype by environment interaction for grain yield of different tef varieties and to identify stable and/or high yielding genotypes across locations. Twenty-one tef varieties were tested at six environments/locations (Jimma/Melko, Omonada, Bedele, Arjo, Areka and Ambo) in South and Southwestern Ethiopia during the 2018 main cropping season using Randomized Complete Block Design (folded RCBD) with three replications. Grain yield and other related traits were recorded and mean performances of these traits and grain yield stability were evaluated using different statistical procedures. The results showed significant differences among tef varieties for grain yield and yield related traits. Combined mean grain yield of the tef varieties varied from 1084.3kg/ha for variety Dukem, to 662.8kg/ha for variety Kena.The proportions of total sum of squares for environment, genotype and GEI for grain yield were 69.4% 8% and 17.5%, respectively. Having the largest proportion of sum of squares, the environment had the highest impact on genotype performance followed by GEI and genotype. The Additive Main Effect and Multiplicative Interaction (AMMI) model also demonstrated the presence of GEI. The first and second interaction principal components axes (IPCA) highly significant (p<0.01) and cumulatively explained 63.4% of the total variation due to GEI.Stability parameters such as Cultivar superiority measure, Stability variance, Yield stability index,AMMI stability value, AMMI and GGE on average identified Heber-1 ,Quncho and Dukem as high yielding and the most stable tef varieties.Whereas, Variety Kena, Wellenkomi, Negus, Felagot and Guduru as low yielding and unstable varieties. Similar result was obtained from GGE biplots analysis showed that Dukem as an ideal variety, while variety Heber-1 and Abola were desirable varieties as they were closer to the ideal variety. Conversely, varieties Kena and Guduru were the least desirable varieties based on GGE biplot. In general, the result of different stability parameters were differs in the selection of the best performing and stable varieties. The results from this study gave valuable information for researchers who were interested to examine the effect of G x E interactions on the performance of tef varieties in the South and Southwest Ethiopian condition. The study used data collected for only one season, which may limit the strength of its recommendation. However, the results are crucial in directing the breeding decision following additional season evaluation of the varieties in the same locations.