干旱调控下小麦RIL群体灌浆期茎秆可溶性碳水化合物积累与转运的遗传分析

Genetic analysis of accumulation and remobilization of water soluble carbohydrates regulated by drought in wheat RIL stem at grain-filling stage

以小麦RIL群体（陇鉴19×Q9086，F8）120个株系及其亲本为供试材料，研究雨养（DS）和正常灌溉（WW）条件下，小麦灌浆期不同发育阶段主茎不同节位可溶性碳水化合物（WSC）含量、转运率及其对籽粒的贡献率，以及穗粒重的遗传特点及各目标性状间的相关性．结果表明：在两种水分条件下，小麦RIL群体各目标性状变异广泛，变异系数在2．7％～62．1％（DS）和1．9％-52．1％（WW），多样性指数在0．61—0．90（DS）和0．64～0．89（WW），且存在超亲分离．各目标性状表型受基因型、水分环境、节位和发育时期的显著影响．其中，WSC含量受发育时期的影响较大，WSC转运率具有显著的水分和节位主导效应，而WSC转运对籽粒的贡献率受基因型、节位和水分的共同作用．开花初期和灌浆中期WSC含量、花前WSC转运率对籽粒的贡献率之间普遍表现为显著或极显著正相关，且干旱条件下其相关系数更高．各目标性状的遗传力较低（hB^2在干旱条件下为0．31～0．56，灌溉条件下为0．44～0．67），控制各目标性状的遗传基因对数在6—29对（DS）和3～19对（WW）．表明该群体对所考察性状有贡献的等位基因在其后代群体中得到广泛分离，其表达易受水分环境的影响，符合典型数量性状特点．

Recombinant inbred lines （RIL, Longjian 19 x Q9086, F8 ） and their parents were un- dertaken to study characteristics of quantitative genetics of water soluble carbohydrates （WSC） accumulation, remobilization and its contribution to grain mass in different main stem internodes at the grain-filling stage as well as the correlations among the target traits under the rainfed （DS） or well- watered （WW） condition. All of the target traits of RIL had wide variations under both water condi- tions. The variation coefficient ranged from 2.7% to 62. 1% under the DS, and from 1.9% to 52.1% under the WW. The diversity index varied from 0.61 to 0.90 under the DS, and from 0.64 to 0.89 under the WW. All tested traits were significantly affected by the genotype, water condition, internode and growth stage. The growth stage exerted strong impacts on the WSC content. The water condition and internode greatly influenced the WSC remobilization rate. But, the WSC contribution rate to grain was jointly controlled by the genotype, water condition and internode. There were significantly positive correlations between the WSC contents at the early flowering and grainfilling stages, the WSC remobilization rate and its contribution rate to grain at pre-anthesis stage, with the higher correlation coefficients under the DS than under the WW. All traits showed low heri-tability under both water conditions （ha2 = 0.31-0.56 under the DS, 0.44-0.67 under the WW）. The numbers of gene pairs controlling all traits ranged from 6 to 29 under the DS, and from 3 to 19 under the WW. It indicated that alleles responsible for all the target traits of RIL showed substantially transgressive segregation and greatly significant sensitivity to the water condition, confirming the characteristics of quantitative traits.