Abstract
The development of new corn hybrids is imperative in present-day agriculture and is integral to tackling the challenges posed by climate change, feeding a growing population, and securing the long-term viability of agriculture. Evaluating combining ability helps predict the performance of hybrid combinations, enabling breeders to select superior inbreds for developing high-yielding hybrids. Thus, this study aimed to assess the GCA and SCA effects of 18 new maize inbreds. Besides, classifying them into a heterotic group. Thirty-six hybrids, derived from crosses between 18 female inbreds and two male testers, were evaluated across three locations. The study assessed the combining abilities of the inbreds and the relative importance of GCA over SCA, the correlation between yield and yield-related traits, classified the inbreds into heterotic groups, and compared the efficiencies of the SCA effect of grain yield method (HSGCA) and the yield method for heterotic grouping. The relative importance of GCA effects over SCA effects underscored the preponderance of GCA over SCA in this set of lines and testers, suggesting that additive gene action played a predominant role in the inheritance of all measured traits. Yield showed significant positive correlations with EL (r = 0.74) and ED (r = 0.86), highlighting the role of secondary traits in yield selection. The HSGCA method was more effective than the SCA method in classifying inbreds. Four hybrids (H-32, H-34, H-18, and H-24) were identified as promising and should be tested in multilocation trials and promoted for commercialization in Egypt to enhance food security.