QTL Analysis For Seed Morphology Related Traits In Cultivated Peanut (Arachis Hypogaea L.)

Peanut is an important oil crop and economic crop in the world.Yield is one of the important traits in peanut.Seed size and morphology is an important measure to yield potential.In this study,a recombinant inbred line(RIL)population containing 195 lines was constructed from a cross between Xuzhou 68-4 and Yuanza 9102 which had large differences in seed morphology-related traits.The RILs were planted in 6 envionments and evaluated the variation of seed length(SL),seed width(SW),ratio of SL to width(SL/W)and hundred-seed weight(HSW).The QTL mapping analysis was carried out based on the SSRs and SNPs genetic map,respectively.The main results were as follows:1.The seed morphology related traits of the RIL population were surveyed in 6 environments.The results indicated that significant differences were observed in the two parental lines for SL,SL/W and HSW except SW.The four traits had large variation in 6 environments and showed normal distribution.Most of the four traits had significantly relation.One line was larger SL,SW,SL/W and more HSW than Xuzhou 68-4.2.A total of 43,31,52 and 41 QTLs were identified for SL,SW,SL/W and HSW with phenotypic variation of 2.2~41.9%,3.9~15.5%,2.9~27.7% and 4.3~35.9%,respectively,based on SSR genetic map previously published.Among them,there were 50 major QTLs and 29 repeated QTLs identified.The QTL clusters associated with multiple traits were detected on A05 and A09 chromosomes.The marker interval Ad05A20650~Ad05A20499 on A05 chromosome contained contained cqSLA05.2 and cqSLA05.3 that can be detected in 2 environments related to SL,cqSL/WA05.2 that can be detected in 4 environments related to SL/W and cqSL/WA05.3 detected in two environments,the cqHSWA05.3 can be detected in 4 environments related to HSW.The other marker interval AhTE0726~AGGS1438 on A09 chromosome contained cqSLA09.1 that can be detected in 3 environments related to SL,cqSWA09.1 that can be detected in 2 environments related to SW,cqSL/WA09.2 that can be detected in 3 environments related to SL/W.The phenotypic mean value of SL,SW and SL/W in the multiple environments was taken to perform conditional QTL analysis for HSW.There were 1,3,and 5 QTLs repeatedly identified for HSW in SL,SW and SL/W variation condition.3.Based on SNP genetic map previously constructed in our lab,43,31,57 and 41 QTLs were identified for SL,SW,SL/W and HSW with phenotypic variation of 3.4~22.1%,5.1~11.5%,2.9~24.3% and 3.6~23.7%,respectively.Among them,there were 22 major QTLs and 20 repeated QTLs identified.The QTL clusters associated with multiple traits were detected on A05 and A09 chromosomes.The marker interval AHMS59649~AHES25540 on A05 chromosome contained cqSLA05.1 that can be detected in 3 environments related to SL,cqHSWA05.1 can be detected in 6 environments related to HSW.The phenotypic mean value of SL,SW and SL/W in the multiple environments was taken to perform conditional QTL analysis for HSW.There were 2 and 3 QTLs repeatedly were identified for HSW in SW and SL/W variation condition.4.Comparing the physical location of these major QTLs detected by the two maps in the peanut genome,there were 4 physical intervals were both detected based on the SSR and SNP genetic maps.For SL trait,one physical interval on the A05 chromosome were both identified based on two genetic maps.There was one physical interval repeatedly detected on A05 and A09 chromosome,respectively,for SL/W trait based on two genetic maps.Anothor physical interval was repeatedly identified on A05 chromosome for HSW based on two genetic maps.