高CO2浓度下水稻穗部性状的QTL分析

QTL Analysis of Panicle Traits in Rice (Oryza sativa L.) Under Free Air CO_2 Enrichment

【目的】了解大气CO_2浓度升高对水稻穗部性状遗传表达的影响,为今后合理筛选育种材料提供依据。【方法】以粳稻Asominori与籼稻IR24所衍生的染色体片段置换系(CSSLs)为材料,在已构建的染色体置换系遗传图谱的基础上,对比分析水稻穗部性状在FACE(约570μmolCO_2·mol-1)和正常大气CO_2浓度(约370μmolCO_2·mol-1)下的变化及其LOD≥3.0时的数量性状位点(QTL)。【结果】FACE下,Asominori和IR24的穗长、一次枝梗数、每穗总粒数、瘪粒数、结实率和着粒密度的表型值均高于对照;而Asominori和IR24所衍生的CSSLs的穗部性状对CO2浓度升高却呈现出正负两种响应,呈正响应且变化最大的置换系为AI9(穗长)、AI30(一次枝梗数)、AI63(每穗总粒数)、AI62(瘪粒数)、AI50(结实率)和AI2(着粒密度);FACE和对照条件下共检出15个QTL,分布在第1,3,4,5,6,7,8,12条染色体上;其中,FACE下检测出8个QTL,对照条件下检测出7个QTL。仅有1个QTL(qPB5-4)在FACE和对照条件下同时被检测到。【结论】筛选出了水稻穗部性状对CO2浓度升高呈极显著正响应的6个置换系,为将来水稻育种提供材料;在FACE和对照下共检测出控制穗部性状的QTL15个,没有检测到控制穗部性状的QTL与环境显著互作的位点。

[Objective] Understanding the effect of elevated CO2 on genetic expression of panicle traits will provide bases for screening some breeding materials under elevated CO2 enviroment in future. [Method] Based on a RFLP molecular linkage map of 65 indica （IR24） chromosome segment substitution lines （CSSLs） with japonica （Asominori） background, the QTL analysis was conducted for panicle traits under ambient atmosphere CO2 concentration （Ambient） and free air CO2 enrichment （FACE, ambient ＋ 200μmol·mol^-1） at LOD≥3.0. [Result] Panicle length, primary branch, spikelet number per panicle, unfilled seed, seed setting rate seed density under FACE were all greater than those of under Ambient; Positive and negative response to elevated CO2 in panicle traits of CSSLs were detected under FACE. Among them, there were six CSSLs largely positively responded to elevated CO2, they were AI9 （panicle length）, AI30 （primary branch ）, AI63 （spikelet number per panicle）, AI62 （unfilled seed）, AI50 （seed setting rate）, AI2 （seed density）; A total of 15 QTL for panicle traits were detected on chromosome 1, 3, 4, 5, 6, 7, 8, 12 under FACE and Ambient, 8 QTL and 7 QTL were discovered under FACE and Ambient, respectively. Among them, only 1 QTL, namely qPB5^4, was simultaneously detected under both FACE and Ambient. [Conclusion] Six CSSLs were significantly positively responded to elevated CO2, and these positive CSSLs will offer materials for future rice breeding; A total of 15 QTL for panicle traits were detected under FACE and Ambient, and no QTL was detected significantly in interaction between QTLs and environment.