QTL Analysis For Pod Size And Shelling Percentage In Peanut (Arachis Hypogaea L.)

Peanut(Arachis hypogaea L.),which is an important oil crop and economic crop,plays vital role in the edible oil security and increasing income for famers.In this study,195 recombinant inbred lines(RIL),derived from a cross between two Spanish type peanut cultivars(Yuanza 9102 ×Xuzhou 68-4)were used to identify QTLs for 4 agronomic traits,including pod length,pod width,pod,100-pod weight and shelling percentage.The main results were as follows:The RIL population and two parents were planted in 5 environments(2013WH,2014 WH,2015WH,2015 XY and 2016WH).Two parents had significant differences in pod size and shelling percentage.All four traits in the RILs possessed extensive variation,showing existence of transgressive inheritance.Two lines were found having higher phenotypic value both in 100-pod weight and shelling percentage.Correlation analysis revealed that pod length,pod width and 100-pod weight had significantly positive correlation,and pod size traits and shelling percentage had significantly negative correlation.Based on the linkage map constructed previously and increasing simple sequence repeat(SSR)markers,a new genetic linkage map with higher density was constructed,the map consisted of 822 SSR makers in 20 linkage groups and covered a total length of 1403.09 c M.A total of 201 QTLs were detected for pod size and shelling percentage with 2.58%~34.71% phenotypic variation,including 58 for pod length,37 for pod width,35 for 100-pod weight,71 for shelling percentage.Among these QTLs,4 intervals deserved attention.In interval A5876~A5872-2,QTLs for pod length can be detected in 5 environments with 16.57%~29.33% phenotypic variation,and QTLs for pod width and 100-pod weight can be detected in 4 environments with 12.23%~34.71% phenotypic variation;In interval AHGS1143~AGGS2124,QTLs for pod width and 100-pod weight can be detected in 4 environments with 11.51%~23.96% phenotypic variation;In interval AHGS0400~AGGS1438,QTLs for shelling percentage can be detected in 3 environments with 12.41%~16.42% phenotypic variation;In interval Ad91I24~AHGS2130,QTLs for shelling percentage can be detected in 4 environment with 10.00%~16.73% phenotypic variation.Using condition QTL analysis 20 QTLs including 4 major QTLs with 11.03%~23.81% phenotypic variation,34 QTLs including 8 major QTLs with 10.30%~19.74% phenotypic variation,and 35 QTLs including 7 major QTLs with 11.03%~16.42% phenotypic variation were repeatedly detected in pod length,pod width and 100-pod weight conditions,respectively.These results revealed that QTLs for shelling percentage repeatedly detected in pod size conditions would independently regulated the shelling percentage,rather than by pod size.After increasing the number of SSR markers on the genetic linkage map,the number of QTL for pod length,pod width,100-pod weight and shelling percentage increased 10,8,3 and 2,respectively,in two same environments,among of which the number of major QTLs repeatedly detected was 2,2,2 and 1,respectively.Most of the repeatedly detected major QTLs confidence interval was shortened.The phenotypic variation of qPLB3.1 increased by 5.11% and the confidence interval was shortened by 8.3 cM.