Combining Ability Analysis of Yield and Yield Components in Maize ( Zea mays L.) Using Line X Tester Method Under Heat Stress

Abstract

In this study twenty-one test crosses generated by crossing seven elite maize inbred lines with three testers was conducted using line x tester cross at Abu-Ghraib Research Station during 2016 autumn season. Parents and their twenty one hybrids were evaluated in a randomized complete block design (RCBD)with three replicates under heat stress( three sowing duets) at the same station in 2017 fall season. To estimate general and specific combining ability effects of the Maize inbred lines and hybrids for yield and yield component of maize under heat stress. Results analysis of variance indicated significant differences for mean squares due to genotypes for all studied traits. Further genetic analysis for combining ability showed that there was significant differences mean square due to parents (inbred lines and testers) GCA for all the studied traits except ear length were not significant in all sowing dates and number of ears per plant in second sowing date for inbred lines of autumn season. Similarly, mean squares due to Line x tester (SCA) were significant differences for all the studied traits except number of ear per plant in second sowing date , ear length in first and third sowing date and number of kernel per row were not significant at third sowing date for autumn season. The inbred line L4 and tester T1 had good GCA effects and cross combination L7*T3 were good specific combiners for grain yield. Generally, mean squares due to GCA of lines, testers and SCA of line x tester interactions were significant for grain yield and most yield related traits indicating the importance of both additive and non-additive gene actions in controlling these traits.