Genetic diversity of early maturing corn hybrids based on phenological and agronomic traits using multivariate statistical methods

Introduction: Corn is one of the most important crops in the world. This commodity is a primary source of food for both humans and animals. Early-maturing corn grows during the early stages of the growing season. This corn variety is suitable for cultivation in regions with a short growing season. Corn hybrids created by crossing two or more pure lines, have a higher grain yield than pure varieties. Improving corn performance through genetic modification is one of the main ways to increase the production of this crop. The present study aimed to evaluate different early-maturing corn varieties to identify the superior hybrid based on phenological and agronomic traits over two growing seasons in the Moghan region.
Materials and methods: In this study, nine corn hybrids, including H1 (KE 79017/5111× K1264/5-1), H2 (KE72012/12× B73), H3 (KE76009/311× B73), H4 (KE77003/3× B73), H5 (KE79015/6222× B73), H6 (OH43/1-42× B73), H7 (K1263/17× S61), H8 (KE72012/12× K1263/1), and H9 (KE76009/311× K1264/5-1), were evaluated in a randomized complete block design with three replications over two growing seasons (2021 and 2022) at the Moghan Agricultural Research Station. This research assessed phenological, morphological, yield, and yield components using multivariate statistical methods to evaluate the superior early-maturing corn hybrids.
Results: The findings revealed significant variations among the hybrids in days from emergence to silk emergence, days to physiological maturity, ear height, number of kernels per row, number of kernel rows per ear, ear diameter, cob diameter, hundred-grain weight, ear yield, and grain yield. The traits of plant height, ear height, kernel depth, ear diameter, and cob diameter were also significantly different across the two growing seasons (2022 and 2023). The mean comparison of the year-by-hybrid interaction showed that the hybrid H6 (OH43/1-42× B73) was the best hybrid in terms of plant height, ear height, kernel depth, ear diameter, and cob diameter in both growing seasons. Based on the phenological traits, the hybrids H7 (K1263/17× S61) with 9.78 ton per hectare ear yield and H2 (KE72012/12× B73)  with 8.71 ton per hectare grain yield showed the best performance among the earliest maturing hybrids. The correlation analysis between the phenological and agronomic traits and the grain yield of the early-maturing hybrids showed that the grain yield had a positive significant correlation with ear yield and ear diameter. The cluster analysis of the nine maize hybrids based on the phenological and agronomic traits divided them into two distinct groups. High-yielding hybrids H1 (KE 79017/5111× K1264/5-1), H2 (KE72012/12× B73), H6 (OH43/1-42× B73), and H7 (K1263/17× S61) were grouped in a distinct cluster. The principal component analysis of the phenological, morphological, yield, and yield components traits for the nine maize hybrids revealed that the hybrid H2 (KE72012/12× B73) with the highest grain yield was among the most stable and superior hybrids among the early-maturing group in the present study.
Conclusion: The early-maturing maize hybrids in this study demonstrated high genetic diversity. Hybrids with a common paternal parent and similar agronomic traits were grouped in a distinct cluster. This reflects the purposeful nature of the evaluated maize crosses, aimed at enhancing grain yield. Based on the results, the hybrid H2 (KE72012/12× B73) has been identified as one of the best-performing hybrids, exhibiting superior yield and combining ability for the Moghan region.