Genetic mapping and quantitative trait loci analysis for pistillate flowers per node and multi-pistillate flower traits in the F₂ cucumber population

Abstract

This study focused on cucumbers’ multi-pistillate flower (MPF) trait, which is essential for high yields. A genetic linkage map was constructed using a population of 219 F₂ plants to analyze quantitative trait loci (QTL) associated with MPF traits. Crossbreeding of EWSCU-809 (MPF) with EWSCU-989 (single pistillate flower: SPF) generated an F₁ hybrid that self-pollinated to form an F₂ population. Based on 244 single nucleotide polymorphic markers across seven cucumber chromosomes, a linkage map facilitated QTL analysis considering average pistillate flowers (PFs) per node and nodes with MPF traits. The results indicated a 9:6:1 epistatic ratio in the F₂ populations, revealing recessive allele control of the MPF trait in gynoecious plants. Three QTLs (qMP2.1, qMP3, qMP7) on chromosomes 2, 3, and 7 were associated with average PFs per node, explaining 5.6 to 10.3% of phenotypic variation. Four QTLs (qMP2.2, qMP3, qMP4, qMP7) on chromosomes 2, 3, 4, and 7 were linked to the presence of nodes with MPF traits, explaining 5.8 to 10.6% of phenotypic variance. Notably, QTL regions overlapped between the two datasets, suggesting pleiotropic ef‍fects, particularly on chromosomes 3 and 7. These reliable QTLs have the potential to improve breeding programs, enhance PF development, and increase cucumber yields.