Stability of yield and yield components in maize hybrids

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. Analizirani su dvogodisnji podaci prinosa i mase 1000 semena kod 24 hibrida kukuruza FAO grupe zrenja 400, 500, 600 i 700. Istrazivanja su izvrsena na dva lokaliteta tokom dvogodisnjeg perioda. Primenom neparametrijskih metoda: Kubingerove i van der Laana i de Kroona, utvrdjeno je postojanje interakcije genotip ? spoljasnja sredina za obe ispitivane osobine a metoda Hildebranda je utvrdila postojanje interakcije za masu 1000 zrna. Stabilnost hibrida procenjena je pomocu neparametrijskih parametara stabilnosti: Si(1)- prosecne razlike rangova u razlicitim sredinama; Si(2)- varijanse rangova; Si(3) i Si(6)- relativnog odstupanja u odnosu na prosecan rang. Na osnovu izracunatih vrednosti parametara stabilnosti utvrdjeni su najstabilniji i najnestabilniji hibridi za svaku FAO grupu zrenja, kod obe ispitivane osobine. Izracunati su koeficijenti korelacije izmedju obe ispitivane osobine i parametara stabilnosti kao i izmedju samih parametara stabilnosti. Iako je izmedju sva cetiri parametra stabilnosti utvrdjena jaka povezanost, ipak se moze govo