QTL Analysis On Effects Of Sowing Date On The Development Of Plant Height In Soybean (Glycine Max L.Merr.) Using A Four-way RIL Population

Soybean[Glycine max?L.?Merr.]is one of the most important oilcrops in the world,plant height?PH?plays an important role on both yield and adaptability.It is known that PH is a complex trait followed quantitative trait inheritance and controlled by genetic basement and environmental factors,and the expression of some quantitative trait loci?QTL?may be various at different stages,in the past decades many studies had been focused on mapping QTL associated with PH,at mature stage and neglected the developmental dynamics which contain a larger mount of genetic information.Combination of unconditional and conditional variable analysis enable mapping QTL for a specific period which is feasible of a more comprehensive understanding of the dynamic expression of the QTLs.Contrasting with two-way cross,four-way cross could provide more linkage information,higher levels of polymorphism and wider statistical inference space,which provide a higher power of detecting QTL.In the present study,dynamic QTL mapping on PH,relative effects of sowing date?ERSD?on PH and absolute effects of sowing date?AESD?on PH were carried out in soybean based on the phenotypic data collected in two sowing dates of a four-way recombinant inbred lines?FW-RILs?population comprised of 160 F_2:7 and F_2:8 derived from the cross?Kenfeng 14×Kenfeng 15?×?Heinong 48×Kenfeng 19?.The objective of our study was to identify QTL for PH during the development in soybean,and to propose the optimal molecular design for improving PH.The main findings were listed as following:?1?A linkage map that included 275 SSR markers on 20 linkage groups was constructed.The order of most markers is consistent with the public genetic map.This linkage map covered 3636.26cM;the average of markers on each LG was 13.75,and the average of distance between markers was 13.22 cM,ranging from 0.01 cM to 33.93 cM.The linkage group?LG?N,A1,D2 and L had anchored most markers?20?.The average length of the linkage groups is 181.81 cM with a range from 49.36 cM?LG D1a?to 319.02 cM?LG D2?.?2?95 unconditional QTL for PH were detected on all 20 linkage groups except LG E linkage group which explain 6.95%-28.35%of phenotypic variation.Among QTL detected,40 were detected over two times.107 conditional QTL for PH were detected on all 20 linkage groups which explain 6.90%-29.46%of phenotypic variation.Among them,44 were detected over two times.?3?50 QTLs for RESD on PH were detected on 18 LGs which explain 0.9-17.2%of phenotypic variation and.Among them,16 QTLs were detected to assosiate with RESD on PH at multiple stages.10 QTLs?qPHR₁,qPHR₆₂,qPHR₄,qPHR₅₁,qPHR₉₂,qPHR₇₃,qPHR₁6₂,qPHR₁0₂,qPHR₁0₃,and qPHR₁3₃?can be detected in consecutive periods of the same year,and 34 QTLs were detected to only at one stage.?4?55 QTLs related to AESD on PH were detected on 19 LGs,which explain 1.00-12.30%of phenotypic variation.14 QTL were identified multiple stages.10 QTL?qPHA₁₁,qPHA₂₂,qPHA₃₂,qPHA₄₂,qPHA₅₁,qPHA₆₂,qPHA₁0₂,qPHA₁9₂,qPHA₁9₄ and qPHA₁9₅?were associated with multiple consecutive periods three?qPHA₆₄,qPHA₁1 and qPHA₁6₁?were detected in two uncontinuous stages,and 41 QTL were detected to associate with AESD on PH only one time.?5?By comparison with public genomic regions,we found 97 QTLs on 19 linkage groups associated with PH that were detected by previous studies in the present study.43 loci interval associated with PH,AESD on PH and RESD on PH were detected at multiple stages.