花生蔗糖含量和油分品质性状的QTL定位分析OA

Peanut(Arachis hypogaea L.)is an important oil seed and cash crop in China.This study aimed to identify major QTLs for sucrose and oil quality traits to provide theoretical support for molecular breeding.A recombinant in-bred line(RIL)population derived from the cross ZLA×DB was used as research material.Phenotypic data for sucrose content,oil content,and fatty acid composition were collected under four environments.A high-density genetic map containing 3415 SNP markers was constructed,and QTL mapping for sucrose content,oil content and fatty acid com-ponents was performed using the composite interval mapping method.A total of 25 QTLs were detected on 11 chromo-somes,with LOD values ranging from 2.7223 to 10.8423 and phenotypic variation explained(PVE)from 5.8933%to 21.5984%.Notably,within the 88.96-101.85 Mb interval on the distal end of chromosome A05,major QTLs for ara-chidic acid(qEA_A05.2,PVE=21.5984%)and stearic acid(qSA_A05,PVE=17.1650%)were co-localized,showing highly overlapping genetic confidence intervals and positive additive effects.This co-localization was consistent with the extremely significant positive correlation between the two traits in the population(r=0.860***).This QTL co-localization region would provide genetic evidence for the carbon chain elongation from C18:0 to C20:0 in peanut and be hypothesized to contain a pleiotropic or tightly linked regulatory locus,serving as a core genetic region control-ling very-long-chain saturated fatty acid synthesis.Additionally,two QTLs for sucrose content(qSC_A06 and qSC_A07)were detected on chromosomes A06 and A07,among which qSC_A07 is a newly identified regulatory locus.QTLs for oil content(qOC_A07,PVE=16.1874%),palmitic acid,and behenic acid were also mapped on multiple chromosomes.This study systematically revealed the phenotypic associations and genetic basis underlying sucrose content,oil content,and fatty acid components in peanut kernels,confirming that oil content and fatty acid composition are relatively inde-pendently regulated,whereas stearic acid and arachidic acid share a highly coordinated genetic mechanism.The results would provide important theoretical basis and candidate loci for key gene discovery and marker-assisted breeding for peanut quality traits.