日本晴/中嘉早17重组自交系产量性状QTL定位

【目的】对产量相关性状进行多年、多环境的QTL分析,寻找能够稳定遗传的产量性状主效QTL,剖析超级早籼稻中嘉早17的高产机理,为选育高产新品种提供有用信息。【方法】以日本晴×中嘉早17构建的重组自交系群体为研究材料。筛选亲本间多态性SSR标记,对群体各家系进行基因型分析,利用Mapmarker/exp 3.0构建分子遗传连锁图谱。群体于2015—2016年,两地三季种植于杭州、海南和杭州,成熟期考察有效穗数、每穗粒数、单株产量、结实率、千粒重、粒长、粒宽和粒厚等产量相关性状。运用Windows QTL Cartographer 2.5检测产量相关性状QTL,运用QTL Network 2.2检测QTL与环境互作效应。【结果】构建的连锁图谱共包含163对SSR标记,73%的标记父母本基因型比例符合1﹕1理论分离比,23%标记显著偏分离,主要偏向父本中嘉早17,图谱总图距约1 479.4 cM,标记间平均距离约为9.08 c M。3个环境下共检测到46个QTL,分布于除第11染色体外的其他染色体上,贡献率变幅为3.78%—25.45%。共有10个QTL在3个环境下能被重复检测到,分别是控制有效穗数的qEP1、qEP2、qEP4a,控制每穗粒数的qNGPE1、qNGPE7,控制结实率的q SRT7,控制千粒重的q TGW2,控制粒长的qGL3和qGL9,控制粒宽的q GW2b;其中qEP1、qEP2、qNGPE7、qTGW2和q GW2b的增效等位来自亲本日本晴;而qEP4a、qNGPE1、qSRT7、qGL3和qGL9的增效等位来自亲本中嘉早17;除此之外,所检测到的每穗粒数、结实率、粒长和单株产量QTL中大部分增效等位基因均来自中嘉早17。产量性状与环境互作分析显示,控制每穗粒数qNGPE1和qNGPE7、控制结实率的q SRT1a和q SRT7、控制单株产量的q YPP1和q YPP7等6个QTL与环境互作效应显著或极显著。此外,在第1、2、7染色体某区段多个与产量相关的QTL成簇分布。【结论】以日本晴×中嘉早17构建的重组自交系群体连锁图谱具有丰富的多态性标记,覆盖水稻基因组的93.64%,可较好地满足水稻重要农艺性状QTL定位要求。利用该套群体检测到多个产量相关性状QTL,其中,多数控制每穗粒数、结实率、粒长和单株产量的QTL的增效等位基因均来自中嘉早17。该结果与中嘉早17的每穗粒数、结实率、单株产量、千粒重和粒长等性状显著明显优于日本晴的结果一致,这些产量增效QTL可能是中嘉早17高产、稳产的遗传基础。

QTL Mapping of Yield Associated Traits of Nipponbare ×Zhongjiazao 17 RIL Population

【Objective】QTL mapping for yield traits were conducted with phenotype data collected from multi-environments, in order to identify stable QTL for yield traits and analyze the mechanism of high yield of super early indica rice Zhongjiazao 17, which will provide useful information for breeding of new varieties with higher yield and better comprehensive characteristics in rice. 【Method】A recombinant inbred lines (RILs) population derived from Nipponbare × Zhongjiazao 17 were used as experimental materials. Then a genetic linkage map was constructed by Mapmaker/EXP 3.0 based on the RILs genotypes which analyzed by polymorphism SSR markers. During 2015-2016, the RILs and two parents were grown in the experimental fields in Hangzhou, Hainan and Hangzhou. The agronomic characters including effective panicles, grain number per panicle, seed setting rate, 1 000-grain-weight, grain length, grain width and grain thickness and yield per plant were investigated. QTL mapping for these traits were detected by Windows QTL Cartographer 2.5 and environment interaction effect was detected by QTLNetwork2.2.【Result】The genetic map was constructed with 163 filtered SSR markers and covered about 1 479.4 cM with an average interval of 9.08 cM. The genotypes of male and female parent of 73.0% makers were segregated as 1﹕1; only 23.0% markers were distorted segregation which was inclined to Zhongjiazao 17. A total of 46 QTLs were mapped on all chromosomes except the 11th with the contribution rate ranged from 3.78% to 25.45%. Ten QTLs, including qEP1, qEP2, qEP4a (QTL for effective panicles), qNGPE1, qNGPE7 (for grain number per panicle), qSRT7 (for seed setting rate), qTGW2 (for 1 000-grain-weight), qGL3, qGL9 (for grain length), qGW2b (for grain width) can be detected on all three environments. The increasing effective allele of qEP4a, qNGPE1, qSRT7, qGL3, qGL9 and most QTL for grain number per panicle, seed setting rate, grain length and yield per plant come from Zhongjiazao 17. Furthermore, some QTLs about different traits exist as clusters on chromosome 1, 2, 7, respectively. Six yield associated traits QTL were also found can significantly interact with environment. 【Conclusion】 The linkage map of RIL derived from Nipponbare × Zhongjiazao 17 has abundant polymorphic makers which cover 93.64% of the rice whole genome, so it is very suitable for QTL mapping for important agronomic traits. Many stable QTLs about rice yield traits were detected using this mapping population, and among them, the alleles which can increase yield of many QTL of grain number per panicle, seed setting rate, grain length and yield per plant were from Zhongjiazao 17. The results were consistent with that the most of these yield traits of Zhongjiazao 17 were better than Nipponbare. These increasing effective alleles of yield associated traits QTL may be the genetic basis of stable high yield of Zhongjiazao 17.