水稻千粒重 QTL qTGW1.1的验证

摘要

This study was conducted to validate a quantitative trait locus (QTL)for 1000-grain weight (TGW)which was previously mapped in a 3.7 Mb region on the long arm of rice chromosome 1 ,and to locate this QTL more precisely.A plant carrying a heterozygous segment extending from RM1 1448 to RM1 1 6 1 5 was selected from the Zhenshan 97 3/Milyang 46 BC2 F5 population.The resulting BC2 F6 and BC2 F7 populations were assayed with SSR markers.Three BC2 F7 plants were identified,carrying heterozygous segments covering the intervals RM1 1448 -RM1 1 522,RM1 1448 - RM1 1 549 and RM1232 - RM1 1 6 1 5 , respectively.Non-recombinant homozygotes were identified from the BC2 F8 populations,from which three sets of near isogenic lines (NILs)in the BC2 F8 ∶9 generation were produced,consisting of two parental genotypes in the intervals RM1 1448-RM1 1 522,RM1 1448-RM1 1 549 and RM1232-RM1 1 6 1 5 ,respectively.Field trials were conducted to measure heading date (HD),TGW,and grain shape traits including grain length and width.Two-way analysis of variance was performed to test the phenotypic differences between two genotypic groups in each NIL set using SAS program.No significant variations were observed on TGW and grain shape in the NIL which was heterogeneous in the interval RM1 1448 -RM1 1 522,whereas significant genotypic effects were detected in the remaining two NILs in which the enhancing alleles were all derived from Zhenshan 97.For HD,no significant effects were detected in the three NILs.Based on comparison among genomic locations of the three heterogeneous regions,qTGW1 .1 was delimited to a 688.8 kb region flanked by RM1 1 522 and RM1 1 554.%对前期定位在水稻第1染色体长臂上3．7 Mb 区间内的千粒重 QTL qTGW1．1进行验证,并提高其定位精度.从珍汕973/密阳46 BC2 F5群体中筛选到1个在 RM11448-RM11615区间杂合的单株,应用 SSR 标记检测其衍生的BC2 F6和BC2 F7群体,筛选得到杂合区间分别为 RM11448-RM11522、RM11448-RM11549和 RM1232-RM11615的 BC2 F7单株各1个.种植3个 BC2 F8群体,筛选在整个分离区间呈单一亲本型的单株,自交后获得在对应区间呈两种基因型的近等基因系各1套,大田种植,考查抽穗期、千粒重、粒长和粒宽,应用 SAS 软件对同一群体中不同基因型间的表型差异进行方差分析.在千粒重和粒形性状上,异质区间为 RM11448-RM11522的近等基因系未呈显著变异,而另2套材料检测到显著的基因型作用,且其增效等位基因均来自珍汕97；对抽穗期,3套材料均未检测到显著作用.通过比较3个异质区间的基因组位置,将qTGW1．1界定于 RM11522和 RM11554之间688．8 kb 的区间内.