Discovery of Elite Alleles for Seed Vigor Traits in Two Populations of Japonica Rice in Taihu Lake Region

Strong vigor of rice (Oryza sativa L.) seed can improve seedling establishment in direct-seeding rice cultivation. The purpose of this study were to detect elite alleles associated with root length, shoot height, and dry weight of seedling from japonica rice varieties growing in Taihu Lake region, and to screen typical carrier genotypes of these alleles. Identification of quantitative trait locus (QTL) and allele analysis were carried out using General Linear Model program in Tassel 2.0 for the natural population and Composite Internal Mapping program in Win QTL Cartographer 2.5 for the recombinant inbred line (RIL) population. Elite alleles and their carrier materials were determined on the basis of the result of QTL analysis. In the natural population consisting of 58 landraces and 36 developed cultivars, 11 simple sequence repeat (SSR) loci were identified to be responsible for the 3 seed-vigor traits with 42 elite alleles. Diantun 502 Xuanzao, Yangdao 6, Kaiqing, Xianhui 429, and C-Bao were typical carrier genotypes of these alleles. In the RIL population derived from Xiushui 79 × C-Bao, 2, 4, and 3 QTLs were identified for root length, shoot height, and dry weight of seedling, respectively. All elite alleles at these loci except for RM525-143 were from C-Bao. In the both populations, loci for root length were located on chromosome 1, loci for shoot height were located on chromosomes 2, 8, and 11, and loci for dry weight of seedling on chromosome 2. More alleles and alleles with larger phenotypic effects were found in the natural population than in the RIL population.

摘要发掘粳稻种子活力性状的优异等位变异和携带优异等位变异的载体材料可为培育适于直播的高活力粳稻品种提供遗传信息和育种材料。以太湖流域粳稻94个品种构成的自然群体和粳稻品种秀水79与粳稻恢复系C堡衍生的247个重组自交家系(RIL)群体为试验材料, 利用斜板发芽法发芽, 调查生长7 d的幼苗根长、苗高和干重3个种子活力性状, 采用Tassel软件中的GLM方法和Win QTL Cartographer 2.5软件中的CIM方法进行种子活力性状的QTL分析, 发掘有利等位变异和相应载体品种。结果表明：(1) 在太湖流域粳稻自然群体中共检测到11个与种子活力性状相关联的SSR标记位点, 共发掘出42个控制种子活力性状的优异等位变异, 其中控制根长的17个, 控制苗高的13个, 控制幼苗干重的12个。携带种子活力性状优异等位变异且效应值较大的载体材料有滇屯502选早、扬稻6号、开青、籼恢429和C堡等。(2) 在RIL群体中共检测到9个与种子活力性状相关的QTL, 其中2个控制根长, 4个控制苗高, 3个控制幼苗干重。除控制幼苗干重的qDW-2a的有利等位变异RM525-143 bp来自秀水79以外, 其余8个位点的有利等位变异均来自C堡。(3) 两类群体均在第1染色体上检测到与根长关联的SSR标记位点, 均在第2、第8和第11染色体上检测到与苗高关联的位点, 均在第2染色体上检测到与幼苗干重关联的位点, 且在自然群体中检测到优于和多于家系群体的等位变异。