Line × Tester Analysis for Combining Ability and Heterosis in Maize (Zea mays L.) for Grain Yield and Yield Attributes

Abstract

The present study was conducted at the Agricultural Research Station (ARS), Peddapuram, Andhra Pradesh, during rabi 2022–23 using a simple lattice design to evaluate 64 maize genotypes, including 44 test crosses, 11 lines, 4 testers and 5 checks. The test crosses were developed through a Line × Tester mating design involving 11 inbred lines and 4 testers. Analysis of variance indicated significant genetic variability among genotypes for all traits, highlighting ample scope for selection. Combining ability analysis revealed that non-additive gene action was predominant for most yield-related traits such as grain yield per plant, ear girth, and 100-kernel weight, while additive gene action was more influential for plant height and kernel traits. Lines PI 8, PI 9 and PI 21 emerged as superior general combiners, while hybrids such as PI 8 × CML451 and PI 17 × CML451 demonstrated strong specific combining abilities. Heterosis analysis showed significant positive heterosis over mid-parent, better parent, and standard checks for several key traits. Noteworthy hybrids included PI 4 × CL02450 for grain yield and ear length, PI 14 × LM13 for earliness and protein content, and PI 303 × LM13 for ear girth and kernel rows per ear. These promising combinations offer substantial potential for developing high-yielding, early-maturing and nutritionally superior maize hybrids.