Peanut (Arachis hypogaea L.) is one of the important vegetable oil and cash crop. High yield is always the predominant objective in peanut breeding and determined by seed number per unit area and seed weight. Seed number per unit area is produced by planting density per unit area×number of pods per plant×number of seeds per pod. Therefore, the genetic dissection of the number of seeds per pod is helpful to explore the gene/locus related to this trait, which provides an important theoretical basis for the molecular breeding of yield in peanut.

A RIL population, derived from Silihong×Jinonghei 3, were planted at Qingyuan experimental station of Hebei Agricultural University in Baoding city, Hebei province in 2018(E1) and 2020(E2). Phenotypic values of traits associated with the number of one seed pods per plant, two seeds pods per plant and multiple pods per plant were investigated at harvest stage. By using the genetic linkage map constructed by laboratory of Peanut innovation team, Hebei Agricultural University and software of QTL Icimapping V4.1(the Inclusive composite interval Mapping (ICIM)), QTL mapping for the number of seeds per pod was carried out under two environments.

The results showed that the rates of one seed pods per plant and two seeds pods per plant were normal distribution, while the rate of multiple pods per plant was skewed normal distribution. A total of 11 QTLs were detected for the three traits, which could explain the phenotypic variation of 4.66%-22.34% and the additive effects of -9.35-9.42. Among of them, 5 QTLs for the rate of multiple pods per plant with explained 3.19% to 22.34% of phenotypic variation were obtained. The additive effect of one QTL from Jinonghei 3 was negative (-4.77), while the additive effect of the other four QTLs from Silihong was positive (3.59-9.42). Two QTLs for the rate of one seed pods per plant were mapped with explained 4.97%-6.43% of phenotypic variation. The additive effects of the two QTLs from Jinonghei 3 were negative (-4.45 and -4.54). Four QTLs for the rate of two seed pods per plant were located with explained 4.97%-6.43% of phenotypic variation. The additive effects of the four QTLs from Jinonghei 3 were negative (-9.35--3.84). Among of these QTLs, 6 QTLs were major QTLs, of which qRMSPA05 was repeatedly detected, and the heritable phenotypic variation was 16.58%-17.34%, and the additive effect was 7.69-8.12.

Six major QTLs and one major stable QTL for multiple pods per plant were identified, which will be helpful for improving the yield traits in peanut. The results can be used as important candidate segments for genetic improvement, and molecular marker assisted selection and fine mapping.