Despite this breeding significance, the genetic mechanism underlying gynoecious sex expression in sponge gourd had remained largely unexplored. To dissect the inheritance pattern, the team evaluated F2 plants, F2:3 progenies and backcross populations derived from the PGY-10 by PSG-223 cross. The phenotypic evaluation pointed to a simple genetic architecture: gynoecy is governed by a single recessive gene, meaning the female-flowering phenotype appears when a plant carries the recessive allele in homozygous form.

With the inheritance pattern established, the researchers turned to bulked segregant analysis combined with whole-genome resequencing. They sequenced DNA pools built from 169 F2 plants and scanned for genomic regions where allele frequencies diverged between the bulks. This analysis identified a major genomic region associated with gynoecy on chromosome 11 of the Luffa_cylindrica_var_P93075_v1 reference genome, giving the team a starting point for finer mapping.

To narrow the interval, the team developed Kompetitive Allele-Specific PCR (KASP) markers across the candidate region and carried out linkage analysis in the segregating population. Seventeen polymorphic KASP markers delimited the gynoecy-associated locus, which the authors designated SG_gy11, to a 1.43 megabase interval on chromosome 11. The region is flanked by two markers, SGMJP_1854186 and SGMJP_3281262, located 1.43 centimorgans and 3.71 centimorgans from the locus, respectively. Markers this close to the target locus are suitable for marker-assisted selection, allowing breeders to track the gynoecy allele without waiting for plants to express the flowering phenotype.

Gene annotation within the mapped interval identified six putative candidate genes associated with reproductive development and hormone-mediated pathways, suggesting their possible involvement in gynoecious sex expression. As the study concludes, this work provides the first genetic evidence of a major recessive gene controlling gynoecy in sponge gourd and identifies closely linked KASP markers for marker-assisted selection. The mapped genomic region and candidate genes offer resources for dissecting the molecular regulation of sex expression and for accelerating the development of gynoecious parental lines in sponge gourd hybrid breeding programs.

Subject of Research: Genetic mapping of gynoecy-regulating genes in sponge gourd using BSA-seq and KASP markers

Article Title: BSA-seq based genetic mapping of gynoecy regulating gene(s) in sponge gourd (Luffa cylindrica L)

Article References: Prajapati, J., Sidhu, M. K., Yadav, I. S., Sarao, N. K., Thangavel, M., & Kumari, A. (2026). BSA-seq based genetic mapping of gynoecy regulating gene(s) in sponge gourd (Luffa cylindrica L). BMC Plant Biology. https://doi.org/10.1186/s12870-026-10288-0

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10288-0

Keywords: sponge gourd, Luffa cylindrica, gynoecy, BSA-seq, KASP markers, chromosome 11, single recessive gene, marker-assisted selection, hybrid breeding, sex expression, candidate genes, genetic mapping