The study was aimed at determining yield stability and adaptability patterns of a set of 65 open pollinated maize genotypes evaluated across four different agro ecologies in Uganda using 5 × 13 α-lattice design replicated twice. Individual location analysis ANOVA results showed mean squares of genotype were statistically highly significant in terms of days to 50% anthesis, anthesis silking interval, grain yield and maize streak virus disease severity score for all environments tested except for grain yield in Ngetta. The highest grain yield was recorded for topcross C9/TA (ECAVL1/CML536) of 9.60 t ha-1 in Bulindi, for top cross C3/TA (Longe5/CML536) of 9.56 t ha-1 in Namulonge. However, they were quite unstable as their ranking was not consistent across environments. The genotype Ambsyn5, C4/TB, FS85 and C9/TB were showed the lowest disease score for MSV. The parent OPV SITUKA MI was with the lowest day requirement for shading pollen and hence it can be utilized in breeding for earliness. The additive main effects and multiplicative interaction (AMMI) analysis results indicated that the tested genotypes were highly influenced by genotype main effects, environment effects and genotype x environment interaction effects; the magnitude of environment and its interaction effect for grain yield was 9.8 times greater than the variation attributed to genotype main effects thus these genotypes were more affected by the environment and their interaction. Based on Finlay and Wilkinson’s sensitivity estimate, genotypes G40, G58, G42, G44, G56, G23, G52 and G53 were identified as the most stable and widely adaptable.
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