QTL analysis of flowering‐related traits by specific length amplified fragment sequencing in melon

Melon (Cucumis melo L., 2n = 24) belongs to the family Cucurbitaceae and is an important vegetable crop. This study aimed to investigate the quantitative trait loci (QTL) of flowering‐related traits to understand the genetic inheritance and candidate gene of flowering‐related traits. The specific length amplified fragment sequencing (SLAF‐seq) technology was used to construct a genetic map of 115 individual plants in the melon F2 population. A total of 82.6 Gb of data were generated using SLAF‐seq. A genetic map was constructed with 10,596 specific length amplified fragment markers in 12 linkage groups, which spanned 1,383.88 cM with an average distance of 0.13 cM between markers. Ten QTL of flowering‐related traits were detected, which explained 2.16–19.34% of the phenotypic variance. The logarithm of the odds (LOD) values ranged from 3.5 to 24.9. Ninety‐four F2:3 families were used for mapping mft and fft in candidate regions by simple sequence repeat (SSR) and cleaved amplified polymorphic sequences (CAPS) markers. The mapping results showed that mft2.1 and fft2.1 were located in the same region, between CmSSR07071 and CmSSR07102. By gene annotation, 36 candidate genes were detected in this region, 26 of which were annotated. Quantitative reverse transcription–polymerase chain reaction (PCR) showed that candidate genes, including WRKY transcription factor and AP2/ERF and B3 domain‐containing transcription factor, were differentially expressed in female and male flowers in the flower budding stages. These genes may provide the theoretical foundation for gene cloning and genetic transformation in melons. Core Ideas A high‐density genetic map spanning 1,383.88 cM was constructed. A total of 10 QTL was located in five linkage groups. Using gene alignment, 26 candidate genes were detected in this region.