Identification Of Quantative Trait Loci Associated With Seed Weight Of Soybean In Muti-developmental Stage,muti-environment,muti-gen Etic Background

To explore the additive(A), epistatic(AA) and quantitative trait locus (QTL)×environment interaction effects (QE) of QTL and QTL on formation, accumulation, and stability of soybean seed across muti-developmnetal stages, muti-environments, and muti-genetic background, for deepen understanding the nature of the yield formation and accelerating the breeding process.The one aim here was to identify conditional and unconditiaonal QTLs of seed weight(delegated by 100-seed weight) expressed from 30 day to 80 day after flower at Habin in 2004, 2005, and 2006, to measure the effects of conditional QTL additive, epistasis and QTL×environment (QE) interaction on the seed wiehgt development, though a population of 143 F_5:9, F_5:10 and F_5:11 recombinant inbred lines developed from the cross of soybean cultivars'Charleston'and'Dong Nong 594'. The anther aim of this study, was to detect QTLs associated with seed weigh at Harbin in 2004, 2005, 2006, 2007, 2008, and 2009, at Hulan in 2006, 2007, and at Suihua in 2006, 2007, at maturity time, to meaure the effects of QTL additive, epistasis and QE interaction on stability of seed wiehgt, though a population of F_5:9, F_5:10, F_5:11, F_5:12, F_5:13, F_5:14 recombinant inbred lines developed from the cross of soybean cultivars'Charleston'and'Dong Nong 594'. The third aim of this study, was to identify QTLs of seed weigh in muti- genetic background across muti-environments at maturity time, to meaure the effects of QTL additive, epistasis and QE interaction on the seed wiehgt at Habin in 2007, 2008, and 2009 though three derived recombinant inbred lines developed from the cross of soybean cultivars'Hefeng25'and'Conrad'including 140 F_2:5, F_2:6 F_2:7 recombinant inbred lines, of soybean cultivars'Hefeng25'and'Maple Arrow'including 117 F_2:6, F_2:7, F_2:8 recombinant inbred lines, and of soybean cultivars'Hefeng25'and'Bayfield'144 F_2:6, F_2:7, F_2:8 recombinant inbred lines, repsectively. Moreover, inheritance of seed weight at maturity time was analyzed using four recombinant inbred lines respectively derived from cross between'Charleston'and'Dong Nong 594', cross between'Hefeng25'and'Conrad', cross between'Hefeng25'and'Maple Arrow', cross between'Hefeng25'and'Bayfield'through mixed major gene plus polygene inheritance models. The result showed:(1) Genetic model of seed weight in different genetic backgrounds and environments1) Seed weight of recombinant inbred lines derived from the cross of soybean cultivars'Charleston'and'Dong Nong 594', were controlled by polygene heritability from 2004 to 2008 at Habin, by two major genes+polygene heritability from 2007 to 2008 at Hulan and Suihua, respectively.2) Seed weight of RIL population derived from a cross between'Hefeng25'and'Conrad', were controlled by two major genes+polygene heritability in 2007 at Habin, by gene drag in 2008 and 2009 at Habin.3) Seed weight of RIL population derived from a cross between'Hefeng25'and'Maple Arrow', were controlled by major genes+polygene heritability from 2007 to 2009 at Harbin.4) Seed weight of RIL population derived from a cross between'Hefeng25'and'Bayfield', were controlled by two major genes+polygene heritability from 2007 to 2009 at Harbin.(2)Identification of dynamic QTL influcing seed weight in different developmental stage1) A moelecular genetic linkage map including 164 SSR markers and 35 RAPD markers, covering 20 linkage groups, was constructed by Sun et al. (2009)^[9]. In this study, unconditional and conditional QTL associated with seed weight, was identified in different developmental stage.2) Ninety-four unconditional QTL influencing 100-seed weight at different developmental stages were identified and mapped onto twelve linkage groups based on three years data. Of these, three unconditional QTLs (swCDC2₁,swCDC2₂,swCDC2₄) were consistently detected in three years. A total of sixty-eight conditional QTL influencing 100-seed weight were identified and mapped onto twelve linkage groups at different developmental stages in different years. Of these, two conditional QTLs (swCDC2₁,swCDC2₂) were consistently detected in three years. Conditional QTL swCDC2₁ and swCDC2₂ was detected among six consecutive measurements from 30 day to 80 day after flower, across three years.3) A total of 17 conditional QTL with a and/or ae effect at some specific stages were identified in 10 linkage groups by conditional mapping. Six conditional QTL(swCDA1₂, swCDC2₂, swCDC2₃,swCDD1b₂,swCDL₁,swCDM₁)was positively associated with seed weight at different developmental stage, anther six conditional QTL(swCDA1₁,swCDA2₁,swCDE₁,swCDE₂,swCDF₂, swCDG₁) was negatively associated with seed weight at different developmental stage, others was positively or negatively associated with seed weight at different developmental stage. A total of 13 conditional QTL had significant ae effect at the different developmental stages. Of them, eight conditional QTL (swCDA2₁ ,swCDC1₁,swCDC2₁,swCDC2₂, swCDD1b₁,swCDD1b₂,swCDD1b₃,swCDF₁) had significant ae effect at different stages in all three environments.4) A total of 35 epistatic pairwise QTL were identified by conditional mapping in different developmental stages . Of them, epistatic effects of three pairs of QTL (swCDC2₁and swCDD1b₂ , swCDC2₁ and swCDL₁ , swCDC2₃ and swCDD1b₁) were detected at three stages. Others were detected at one or two stages.(3) Iedntification of QTL underling soybean seed weight in multi-environments at maturity time1) A total 20 QTL were detected in a RIL population derived from a cross between'Charleston'and'Dong Nong 594'. Of them, swCDFC2-2 (associated with satt460) was identified in ten tested enviroments, Other 19 QTL were detected in at least three environments. These QTL was better for marker assistant selecting.2) A total of 17 QTL with a and/or ae effect were identified in 9 linkage groups. Of them, seven QTLs(swCDFA1-1,swCDFA1-3, swCDFC2-2 ,swCDFD1b-1, swCDFE-2,swCDFE-3,swCDFL-2)was positively associated with seed weight at different environment, four QTLs ( swCDFA1-2 , swCDFB2-1 , swCDFC2-3 ,swCDFD1a-1), was negatively associated with seed weight at different environment, other 9 QTLs was positively or negatively associated with seed weight at different environment. Of them, one QTL(swCDFA1-3)only have a effect, nine QTL (swCDFC2-1, swCDFC2-4, swCDFD1a-2, swCDFD1b-2, swCDFE-1, swCDFG-1, swCDFL-1, swCDFN-1, swCDFN-1)only have ae effect, other 10 QTL have both a effect and ae effect.3) A total of 37 epistatic pairwise QTL have aa effect and aae effect. Of them, 15 epistatic pairwise QTL only have aae effect, one epistatic pairwise QTL only have aa effect, others have aa effect and aae effect.(4) Iedntification of QTL underling soybean seed weight in multi-genetic backgound at maturity time1) 18, 11, 17 QTL, associated with seed weight at maturity time, were identified, respectively through three RIL populations deived from cross between'Hefeng25'and'Conrad', cross between'Hefeng25'and'Maple Arrow', cross between'Hefeng25'and'Bayfield', based on three constructed mlecular genetic maps[102-104] . A total of 13 QTL (respectively associated with satt233,satt424,satt583,satt460,satt277,satt383,satt428,satt263,satt302,satt354,satt555,satt527,satt153) could be detected in more than two populations. Only one QTL (associated with satt460) was detected in more than two populations and more than two environments.2) 18, 11, 17 QTL with a and/or ae effect were identified. A total of 13 QTL with a and/or ae effect were detected in more than two two populations.3) 39, 16, 20 epistatic pairwise QTL of three RIL population deived from cross between'Hefeng25'and'Conrad', cross between'Hefeng25'and'Maple Arrow', cross between'Hefeng25'and'Bayfield', have aa effect and aae effect. A total of 26 epistatic pairwise QTL have similar or same aa effect among three RIL populations.