Heterosis and combining ability for grain yield and yield component traits in maize (Zea mays L.)

Abstract

Fifteen hybrids obtained by crossing five Lines with three Testers were evaluated to study heterosis and combining ability for grain yield per plant and its component traits. Further, heterosis studies revealed that almost all the Line x Tester combinations registered significant positive heterosis over both mid and better parents for grain yield per plant. The crosses namely BM-256 x BM-85, BM-256 x BM-143, BM-3 x RNBL-4351, BM-421 x BM-85 recorded higher level of significant relative heterosis and heterobeltiosis for grain yield per plant. Combining ability analysis suggested the preponderance of non-additive type of gene action for majority of the traits viz., days to 50% tasseling, days to 50% silking, 100-seed weight, grain protein content and grain yield per plant. Out of the five lines tested in the present investigation, genotypes namely BM-421 and BM-256 recorded significant general combining ability effects in desirable direction for majority of the traits; while the tester, BM-143 recorded significant general combining effect for grain protein content. None of the 15 Line x Tester combinations recorded significant sca effect for grain yield per plant. The cross BM-77 x BM-85 recorded significant sca effect for plant height and grain protein content.