Study on Combining Ability and Gene Effects Estimation in Some Sweet Corn Inbred Lines (Zea mays L. var saccarata) by Line × Tester Method

In breeding programs determination of gene effects and general and specific combining ability for screening of test crosses is necessary. In order to estimate the genetic variance components and the general and specific combining ability of sweet corn lines, an experiment was conducted using 8 sweet corn S6 inbred lines (including 4 maternal and 4 paternal lines) by line × tester mating design in 2019, at the Agricultural and Natural Resources Research and Education Center of Khorasan Razavi Province, Mashhad, Iran. The obtained test cross hybrids were evaluated in a randomized complete block design with 3 replications in 2020. The results of line, tester and line × tester analysis for most of measured traits showed significant differences (p < 0.05). The σ 2 gca / σ 2 sca ratio for grain yield was equal to 0.1, showed that while both additive and dominance effects play a role in controlling this trait, but dominance effect was higher. The results for general combining ability of L3 and T1 lines showed positive and significant GCA effect for grain yield. Also, the specific combining ability of grain yield showed that T4 × L2, T1 × L3 and T3 × L1 had the highest SCA rate. In this study, in terms of grain yield, T1 × L3, T4 × L2 and T1 × L4 with 33.96, 30.47 and 27.85 tons per hectare had the highest green ear yield, respectively. These combinations can be as the hybrids with high yield potential in advanced breeding programs for release of new sweet corn varieties.