Stability of yield and yield components in maize hybrids

Abstract

Two-year grain yield and 1000-grains mass data of 24 maize hybrids of FAO maturity groups 400, 500, 600, 700 were analyzed. Investigations were performed at the two environments in two years. Nonparametric methods of the Kubinger and the van der Laan-de Kroon showed genotype x environment interaction for both investigated features, and method of Hildebrand showed interaction for 1000-grains mass. Maize hybrids stability was estimated with stability parameters: Si(1)- the mean of the absolute rank differences over environments, Si(2)- the common variance of the ranks, Si(3).and Si(6): the sum of the absolute deviations and sum of squares of rank for each genotype relative to the mean of ranks, respectively. On the basis of the stability parametar values, the most stable and the most unstable hybrids were estimated for each FAO maturity group, for both investigated features. Correlation coefficients between both investigated features and stability parameters and for all pairs of stability parameters were computed. In spite of the positive correlations estimated between all four stability parameters, we can make two groups: the first group formed: Si(1)- the mean of the absolute rank differences over environments and Si(2)- the common variance of the ranks and the second group formed: Si(3) and Si(6)- the sum of the absolute deviations and sum of squares of rank for each genotype relative to the mean of ranks respectively.