Comparative Evaluation of Three Methods for Heterotic Grouping in Yellow Maize

Evaluation and classification of inbred lines are crucial for accelerating the development of high-yielding, superior maize hybrids. This study aimed to assess combining ability effects of diverse maize inbred lines using the line × tester mating design, and to compare the effectiveness of three methods, HSCA, HSGCA, and HGCAMT, for classifying inbred lines into heterotic groups. The plant materials included two distinct sets of yellow maize inbred lines, each set comprising 21 diverse inbred lines crossed with two testers to generate 42 hybrids. The resulting hybrids in each set and two checks, i.e., SC.168 and Corteva SC.3444, were evaluated at Sakha and Gemmiza Agricultural Research Stations during the 2024 growing season using a randomized complete block design with three replications. The results indicated that the HSGCA method provided the highest breeding efficiency and identified the superior inter-group hybrids, followed by HSCA and HGCAMT. Four inbred lines, Inb-02, Inb-07, Inb-08 and Inb-14 from set-1 and six inbred lines, Inb-28, Inb-29, Inb-32, Inb-33, Inb-37 and Inb-41 from set-2 had desirable GCA effects for high grain yield. Furthermore, five hybrids, H-13, H-14, H-15, H-63 and H-73, significantly outyielded two checks. Hence, they were identified as promising hybrids in the present study and recommended for further multi-environment evaluation.