Novel Allelic Gene Variations in () Were Identified in a Genetic Population of Melon ( L.).

Carpel number (CN) is an important trait affecting the fruit size and shape of melon, which plays a crucial role in determining the overall appearance and market value. A unique non-synonymous single nucleotide polymorphism (SNP) in () is responsible for the variation of CN in ssp. (hereafter ), but it has been unclear in ssp. (hereafter ). In this study, one major locus controlling the polymorphism of 5-CN (multi-CN) and 3-CN (normal-CN) in was identified using bulked segregant analysis (BSA-seq). This locus was then fine-mapped to an interval of 1.8 Mb on chromosome 12 using a segregating population containing 1451 progeny. is still present in the candidate region. A new allele of , which contains five other nucleotide polymorphisms, including a non-synonymous SNP in coding sequence (CDS), except the SNP reported in , was identified in . A cis-trans test confirmed that the candidate gene, , contributes to the variation of CNs in . The qRT-PCR results indicate that there is no significant difference in the expression level of in the apical stem between the multi-CN plants and the normal-CN plants. Overall, this study provides a genetic resource for melon fruit development research and molecular breeding. Additionally, it suggests that has undergone similar genetic selection but evolved into an independent allele.