Optimizing Selection Strategies for Corn Breeding: A Comprehensive and Systematic Analysis of Full Diallel Populations

The development of new corn varieties is necessary to meet the corn demand. Using full diallel crosses is a method for developing high-yielding hybrid corn. This development requires systematic selection methods that incorporate various approaches in developing selection indices. This study aimed to develop a selection index concept for two full diallel cross populations and select potential hybrid crosses for preliminary yield evaluation. The study involved two populations of 100 corn seed genotypes from full diallel crosses (90 F1 genotypes and 10 selfing elders) and five check varieties per population, planted using a Type II Augmented RCBD in eight blocks. Agronomic characteristics were analyzed using analysis of variance, heritability, factor analysis, and path analysis, with selection criteria aligned with heterotic potential, specific combining analysis, and heterobeltiosis. Analysis revealed significant genetic variation and moderate-to-high heritability for most traits. Correlation, factor, and path analyses identified cob diameter, number of rows per cob, and seeds per row as optimal selection criteria. Selection indices were developed by integrating standard heterosis, specific combining ability, and heterobeltiosis, with weights based on heritability and direct effects. Forty-four hybrid crosses showed potential for preliminary yield tests, with seven having the best final index compared to the reference variety. The p17 × p23 cross had the best potential for the final index. This study demonstrates the effectiveness of integrating multivariate analysis and selection indices in developing superior hybrid corn crosses. Further optimization is recommended through preliminary yield tests and molecular approaches.