QTL Analysis Of Pod And Kernel Size Related Traits In Peanut(Arachis Hypogaea L)

Peanut(Arachis hypogaea L)is the cash and oil crop in the world.At present,the important task is to improve the genetic traits of peanut and make it productive in the limited acreage.The yield trait of peanut is one of the most concerned traits.As is well known,the size of pods and kernels is the direct factor determining the yield of peanuts,and the research about the yield traits of peanut is very limited,this study aims to provide theoretical basis for gene cloning and molecular mechanism analysis for peanut pod and seed size by obtaining the mocular markers closely linked to yield traits of peanuts.A recombinant inbred line(RIL)population containing 188 lines was constructed with parents Zhonghua 16 and J11,which have significant difference in pod and seed size.A genetic map was constructed by analyzing SSR morcular markers.Meanwhile,Combined with the phenotypic data of 8 traits for 2 years,QTL mapping and analysis were conducted.The results are following:1.A genetic linkage map was constructed.The map contained 21 linkage groups and 289 SSR markers,the map length is 947.3 cM and the average distance between markers is 3.28 cM.The chromosome B06 has the top number of markers and the A04a has the highest marker density.The length range of chromosomes is between 4.91cM?84.17cM,and the marker number is between 3?38.2.The data for pod and kernel size in the RIL populaton were analysized.a The result of statistical analysis shows that the phenotypic traits have large variation between different individuals of the RIL population,and each trait has a normal distribution under different environments,which accorded with the genetic distribution of quantitative traits.According to the result of the correlation analysis and variation analysis,there is a significant correlation between pod length,pod width,hundred pod weight,seed length,seed width and seed weightand kernel related traits in the two environments.Of these traits,the pod width and kernel width areless affected by the environment and are more stable.3.QTL for pod size and kernel size were identified.Based on the genetic linkage map along with the phenotypic data of 2017 and 2018,a total of 85 QTL related to pod sizcand kernel size were identified,and the phenotypic variation explained was between 3.23?33.01%,29 QTL of them were major QTL with phenotypic variation explained 10.21?33.01%.A total of 9 co-localization intervals controlling same traits were observed,and according to the result,the QTL for seed length,seed width,hundred seeds weight,the ratio of length to width of seed,hundred pods weight and the ratio of length to width of pod were observed repeatedly,and the phenotypic variation explained of QTL for seed length,seed width and the ratio of length to width of seed were more than 10%.These stable and major QTLs are important for molcular marker-assisted breeding and worth being further studied;a total of 14 co-localization intervals controlling different traits were observed,and 2 of them controlling seed length and the ratio of seed length to width,which indicates a close linkage between the two traits.