Parametric Statistical Methods for Evaluating Barley Genotypes in Multi-environment Trials

摘要

THE CURRENT study aimed at assessing twelve genotypes of barley in a randomized complete blocks design with 3 replications across 8 environments (the combinations of 2 years x 2 locations x 2 sowing dates) during 2008/2009-2009/2010 seasons in Egypt.Significant differences were observed among barley genotypes for heading date, grain filling, number of spike/m2, spike length, thousand grain weight and grain yield (ardab/fed). Combined analysis of variance of grain yield of twelve genotypes tested ineight environments showed highly significant (p<0.01) differences between the genotypes, between environments and for GEI, of all traits under study, suggesting differential response of genotypes across testing environments and the validity of stabilityanalysis. To quantify yield stability, six parametric stability statistics were calculated (bj , S2di , Rj2, Wj2, S2i and CVj). According to the stability parameters, for grain yield of barley genotypes, the results revealed that genotypes Giza 123, Giza129, Giza 127, G4, G2, G6 and G8 were more stable genotypes for 7, 7, 7, 5, 4, 4 and 4 out of all 7 stability statistics used, respectively. Thus, these genotypes would be considered to be more stable than others for these statistics. This implies therefore that there genotypes are of low contribution to the genotypic by environment interaction. These genotypes may be utilized as donor parents for stability in barley improvement programs, and could be recommended to be as commercial stable high yielding cultivars. Highly significant rank correlations coefficient were found among S2di, W2i and R2 implying their close similarity and effectiveness in detecting stable genotypes and they are equivalent in measuring stability. Hence any one of these parameters could be used to describe genotypes stability. Our results showed that high-yielding genotypes can differ in yield stability, and suggest that yield stability and high grain yield are not mutually exclusive.