Combining Ability Analysis and Determination of Controlling Gene Action for Yield and other Key Traits of Open Pollinated Maize (Zea mays L.) Varieties and their Topcrosses with Inbred Line Testers in Uganda (Published)
The study was carried out with 38 top crosses which were evaluated with parents and checks. The objective of the study was to determine combining ability and the type of controlling gen action for yield and yield related traits of 19 OPVs using their top crosses in terms of grain yield, days to anthesis, plant height and grain texture. Line x tester analysis result of mean squares of ANOVA revealed statistically significant interaction of genotypes (female, male and crosses) with environment variations for selected traits under study. Baker’s ratio of 1.00 for grain yield, suggests that additive genes were highly most important than non-additive for the control of yield. The higher value of broad sense coefficient of genetic determination (H) was high for yield, days to anthesis, plant height and grain texture. Female parent KC2014 and male parent inbred line TA (CML536) had significantly positive GCA effect for grain yield. These parents were the best general combiners for grain yield across sites. Similarly, female parent OPVs (MM3, Longe 5, Longe 5D, SITUKA MI and VP MAX) and male parent inbred line TB (CML202) had highly significant negative GCA for days to anthesis, indicated that these parents can breed for earliness. Therefore, the exhibited variations between OPVs in terms of the GCA and SCA effects can be exploited to produce topcrosses which will help in selection of parents for hybrid development and variety improvement.