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利用以籼稻IR24为受体亲本、粳稻Asominori为供体亲本的66个染色体片段置换系,分别与受体亲本IR24杂交构建1套对应的F1群体,研究杂种优势位点。以中亲优势值作为杂种优势QTL检测的基准表型值,结合新构建的基因型图谱,利用QTL IciMapping软件的逐步回归和极大似然估计结合的方法,检测杂种优势QTL。结果表明,各置换系对应的F1群体,在4个环境(2007年南京、2007年南昌、2008年南京、2008年南昌)下,共检测到53个与产量构成性状相关的杂种优势位点。其中只发现1个杂种优势位点能在多个环境重复检测到,即来自第1染色体与标记RM488紧密连锁的位点。该位点在杂合状态下增加F1的株高。22个位点在杂合状态下具有增效作用,占总位点数的41.51%;LOD值变幅为3.06~7.25,贡献率变幅为3.74%~18.5%。31个位点在杂合状态下具有减效作用,LOD值变幅为3.07~9.70,贡献率变幅为0.45%~30.78%,这些具有减效作用的位点主要控制单株产量、每穗实粒数和结实率等性状,与籼粳杂种不育基因密切相关。
Sixty-six chromosome segmental substitution lines with indica rice IR24 as parent and japonica rice Asominori as donor’s parents were used to construct a set of corresponding F1 populations by crossing with the recipient parent IR24 respectively to study heterosis sites. Using the mid-parent heterosis value as the benchmark phenotype for heterosis QTL detection, combined with the newly constructed genotype map, the QTL for heterosis was detected by using stepwise regression and maximum likelihood estimation of QTL IciMapping software. The results showed that F1 populations corresponding to each substitution system detected 53 heterosis sites related to yield traits in 4 environments (Nanjing 2007, Nanchang 2007, Nanjing 2008 and Nanchang 2008). Only one heterosis locus was found to be detected repeatedly in multiple environments, ie, the site from chromosome 1 closely linked to the marker RM488. This site increased F1 plant height in a heterozygous state. Twenty-two loci had a synergistic effect in the heterozygous state, accounting for 41.51% of the total number of loci. The LOD value ranged from 3.06 to 7.25 and the contribution rate ranged from 3.74% to 18.5%. The 31 loci had a synergistic effect in the heterozygous state. The LOD value ranged from 3.07 to 9.70 and the contribution rate ranged from 0.45% to 30.78%. These loci with the reduced effect mainly controlled the yield per plant The grain number and seed setting rate were closely related to the CMS gene of indica and japonica hybrids.