Evaluation of genotype × environment interaction and grain yield stability of different bread wheat genotypes using non-parametric methods

Water scarcity is the most essential limiting element of agricultural production, particulary in arid and semi-arid areas throughout the world. The line × environment interaction is a major challenge in the study of quantitative characters because it reduces yield stability in different environments and also it complicates the interpretation of genetic experiments and makes predictions difficult. In this regard to analysis of line × environment interaction and determine the yield stability of bread wheat genotypes, 15 new bread wheat lines along with Aftab cultivar were evaluated in a randomized complete block design with three replications in four experimental field stations (Gachsaran, Khoramabad, Moghan and Gonbad) during three cropping seasons. Results of combined analysis of variance indicated that the effects of environments, line and line × environment interaction were significant, suggesting that the lines responded differently in the studied environment conditions. So, there was the possibility of stability analysis. According to mean rank of nonparametric stability parameters, the lines G1, G3, G7 and G15 with the lowest value for mean rank were stable, whereas lines G2, G6, G8 and G10 with highest values were unstable. Also, the results indicated that the nonparametric statistics Si(3), Si(6), NPi(2), NPi(3), NPi(4), KR and Top were associated with mean seed yield and the dynamic concept of stability. Therefore, these methods were suitable for selecting stable and high yielding lines in bread wheat. Finally, G7 line with average grain yield and high general stability was the top line of this test, which after additional tests can be a candidate for a new cultivar to introduce.