Quantitative trait locus mapping reveals the genomic regions associated with yield-related traits in maize (Zea mays L.)

Maize, a one of the cereal crops, serves as the staple food for numerous people across the world. Maize breeding programmes primarily aim to enhance the yield potential of newly developed cultivars. This objective can be accomplished either by direct selection for increased grain yield or by indirect selection for traits closely associated with yield. The present study was carried out in two environments viz., Coimbatore (E1) and Vagarai (E2) to locate QTLs associated with yield-related traits in a recombinant inbred line (RIL) population that resulted from a cross between UMI79 and UMI 936(w). A total of seven yield-related traits (Ear weight, ear diameter, ear length, kernel row number, kernel number per row, 100-kernel weight, and grain yield) were evaluated across the two environments. The QTLs were mapped with the support of genotyping-by-sequencing based SNPs genetic linkage map which contains 1516 markers and spans 10 chromosomes and covers an overall distance of 6924.7 centimorgans. A total of 22 QTLs were discovered across these environments and best linear unbiased predictors, with four of these QTLs being common across them. The study pinpointed three stable QTLs (qEW-6, qEL-2, and qKRN-5), each contributing > 10% of the phenotypic variance in ear weight, ear length, and kernel row number, respectively. Within these QTL regions, 109 protein-coding genes were identified. Gene ontology analysis revealed these genes roles in development, reproduction, and growth. Several candidate genes, including MADS-box transcription factors, serine carboxypeptidase, and E3 ubiquitin-protein ligase, are well known for their role in yield-related traits of maize, and other cereal crops were among those identified. These findings provide valuable information for maize breeders aiming to enhance grain yield-related traits through marker-assisted breeding.