QTL Mapping For Pod And Seed-Related Traits In Cultivated Peanut(Arachis Hypogaea L.)

Peanut(Arachis hypogaea L.)is an important cash crop and oil crop in worldwide.It is an important task of peanut breeding to improve the genetic traits of peanut and maximize its production potential.Peanut yield is one of the most concerned traits that were well known that peanut pod and seed size are key factors in determining yield.To analyze yield-related traits,especially the genetic laws of pod and seed traits.The experimental materials of this study were 315 recombinant inbred lines(RIL)obtained from a cross by a large common varieties jihua5 and a small pod type the US mini-core germ plasm resources M130.Constructing 2 genetic maps of cultivated peanut,and combined with phenotypic data of peanut pods and seed-related traits in 7 environments from 2017 to 2020 for QTL analysis.To obtain molecular markers closely associated with peanut pods and seed traits.It provides a theoretical basis for the cloning of functional genes and the molecular mechanism of peanut pod and seed size formation.The results are as follows:1.Phenotypic data of pod and seed-related traits in parental and RIL populations were statistically analyzed.The results showed that there were significant differences between the two parents;The maximum and minimum values were higher than those of the parents,and the positive or negative super parent advantages were appeared;Under different environments,the measured values of each trait are normal distribution,which accords with the genetic distribution law of quantitative traits;The results of correlation analysis and ANOVA showed that 8 phenotypic data of peanut pod length,pod width,pod thickness,seed length,seed width,seed thickness,hundred pods weight and hundred seeds weight showed significant or very significant correlation under 7 environments;The generalized heritability of each trait is between 31%and 91%.2.The genetic linkage map(Mapl)containing SSR、SRAP and TRAP markers was constructed.The total length of the map was 1360.38 cM,the length of single linkage group was 39.59-101.05 cM,containing 4-50 molecular markers,and the average distance between markers was 3.75 cM.Among them,the linkage group with the least marker and most marker number was B06 and B09,respectively.Twenty-nine markers did not match to the chromosome,was named Unknown linkage group.3.According to Map 1,combined with the phenotypic data of pod and seed-related traits in 7 environments,77 QTLs related to traits were detected,with the LOD value of 3.014-11.693,and the PVE of each trait was 3.013%-13.098%.Among them,6 QTLs were related to pod length;9 QTLs were related to pod width;12 QTLs were related to pod thickness;9 QTLs were related to seed length;12 QTLs were related to seed width;11 QTLs were related to seed thickness;10 QTLs were related to hundred-pod weight;8 QTLs were related to hundred-seed weight.The number of major QTL with PVE>10%is 3;21 QTLs were detected in two or more environmental;6 QTL hot spots.4.A high-density genetic linkage map(Map2)was constructed,containing 20 linkage groups and 2796 SNP markers covering the genome 1191.35 cM.The length of a single linkage group is 13.45-112.141 cM,containing 38-297 molecular markers,and with an average distance of 0.426 cM between the markers.The maximum length of the genome covered by the A03,the minimum length of the genome covered by the A10,the linkage group with the least marker and most marker number was A10 and B08,respectively.5.According to Map 2,combined with the phenotypic data of pod and seed-related traits in 7 environments,46 QTLs related to traits were detected,with the LOD value of 2.445-4.630,and the PVE of each trait was 5.251%-10.826%.Among them,5 QTLs were related to pod length;9 QTLs were related to pod width;6 QTLs were related to pod thickness;4 QTLs were related to seed length;2 QTLs were related to seed width;7 QTLs were related to seed thickness;8 QTLs were related to hundred-pod weight;5 QTLs were related to hundred-seed weight.The number of major QTL with PVE>10%is 3;4 QTLs were detected in two or more environmental;4 QTL hot spots.In this study,two genetic linkage maps were constucted and phenotypic data of 8 pod and seed related traits in 7 environments,6 Major QTLs and 10 QTL hot spots were detected,which will lay a solid foundation for fine mapping of pod and seed related genes and further mining of candidate genes related to pod and seed in peanut.