Understanding the genetics of important traits in quality protein maize (Zea mays L.) by Line by Tester analysis

Abstract

Maize (Zea mays L.) is among the top ten most valuable crops and livestock products. Maize demand and production are continuously rising. The nutritionally rich quality proteins maize (QPM) has almost two times as much lysine as well as tryptophan, amino acids which then the conventional maize varieties. In this study, genetics of important traits in quality protein maize were determined using a Line by Tester matting design. The 45 hybrids were obtained via Line by Tester crossing of 15 lines and 3 testers. The parents and their hybrids were evaluated under two environments. A significant amount of variation was recorded for most of the traits studied. Parental genotypes L2, L6, T2, L8, L7 and L14, exhibited negative and considerable general combining ability (GCA) effects for days to flowering and maturity. L7 x T2, L13 x T3, L10 x T1, L1 x T1, L9 x T2, L5 x T1, L12 x T2, L11 x T3, L10 x T3, L14 x T1 and L6 x T1 were identified with suitable yield and component traits. Crosses L5 x T1, L3 x T1, L12 x T2, L7 x T3, L1 x T2 and L13 x T1 were identified for quality traits. Heterosis over the mid parent crosses L13 x T1 showed highest negative and significant followed by L6 x T1, L12 x T2, L14 x T2 and L2 x T1 for days to 50 per cent tasselling. A significant correlation for the lysine content was determined between F1 mean and specific combining ability (SCA) effects. Overall, this work provides the useful insights into the genetics of important agronomical and biochemical traits of quality protein maize.