Identification of AhFPA1 as the causal gene underlying qEFT13.1, a key QTL for early flowering in peanut

A major QTL, qEFT13.1, for flowering time in cultivated peanut, was fine-mapped to a 169-kb interval on chromosome 13, and AhFPA1, a homolog of AtFPA, was identified as the causal gene through functional validation. Flowering time serves as a key agronomic trait that significantly impacts yield, quality, and environmental adaptation in cultivated peanuts (Arachis hypogaea). Here, the fine-mapping of the locus and an investigation of its causal gene are presented. In this study, the early-flowering genotype Jihua 23 and the late-flowering genotype SN012 were selected to construct a genetic population for mapping key genes controlling flowering time. Based on phenotypic data from the F₂ and F_2:3 populations, a major-effect QTL, qEFT13.1, was identified on chromosome 13 using a combination of QTL-seq and conventional QTL analysis. A derived population consisting of 3,426 F_3:4 families was utilized for fine-mapping, narrowing down the qEFT13.1 locus to a 169-kb genomic interval, which harbored 20 genes. Integrated gene function annotation, candidate gene sequence analysis, and expression profiling suggested that AhFPA1, a homolog of the Arabidopsis autonomous flowering pathway gene AtFPA, is the candidate gene regulating flowering time in peanut. Overexpression of AhFPA1 in transgenic Arabidopsis revealed its function in accelerating flowering time. These results enhance our understanding of the genetic mechanisms governing early flowering in cultivated peanut, offering valuable insights for the breeding of early-maturing varieties.