Liu Liangfeng, Lai Yanyan, Cheng Jinping, Wang Ling, Du Wenli, Wang Zhoufei, Zhang Hongsheng
The Laboratory of Seed Science and Technology, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing Jiangsu, PR China.
PLoS One. 2014 Dec 23;9(12):e115732. doi: 10.1371/journal.pone.0115732. eCollection 2014.
Seed vigor is an important characteristic of seed quality. In this study, one rice population of recombinant inbred lines (RILs) was used to determine the genetic characteristics of seed vigor, including the germination potential, germination rate, germination index and time for 50% of germination, at 4 (early), 5 (middle) and 6 weeks (late) after heading in two years. A total of 24 additive and 9 epistatic quantitative trait loci (QTL) for seed vigor were identified using QTL Cartographer and QTLNetwork program respectively in 2012; while 32 simple sequence repeat (SSR) markers associated with seed vigor were detected using bulked segregant analysis (BSA) in 2013. The additive, epistatic and QTL × development interaction effects regulated the dry maturity developmental process to improve seed vigor in rice. The phenotypic variation explained by each additive, epistatic QTL and QTL × development interaction ranged from 5.86 to 40.67%, 4.64 to 11.28% and 0.01 to 1.17%, respectively. The QTLs were rarely co-localized among the different maturity stages; more QTLs were expressed at the early maturity stage followed by the late and middle stages. Twenty additive QTLs were stably expressed in two years which might play important roles in establishment of seed vigor in different environments. By comparing chromosomal positions of these stably expressed additive QTLs with those previously identified, the regions of QTL for seed vigor are likely to coincide with QTL for grain size, low temperature germinability and seed dormancy; while 5 additive QTL might represent novel genes. Using four selected RILs, three cross combinations of seed vigor for the development of RIL populations were predicted; 19 elite alleles could be pyramided by each combination.
种子活力是种子质量的一个重要特征。在本研究中，利用一个水稻重组自交系（RIL）群体，在两年的抽穗后4周（早期）、5周（中期）和6周（晚期）测定种子活力的遗传特性，包括发芽势、发芽率、发芽指数和50%种子发芽所需时间。2012年分别使用QTL Cartographer和QTLNetwork程序共鉴定出24个与种子活力相关的加性和9个上位性数量性状位点（QTL）；2013年利用混合分组分析法（BSA）检测到32个与种子活力相关的简单序列重复（SSR）标记。加性、上位性以及QTL×发育互作效应调控水稻干熟期发育进程以提高种子活力。每个加性、上位性QTL以及QTL×发育互作所解释的表型变异分别为5.86%至40.67%、4.64%至11.28%和0.01%至1.17%。不同成熟阶段的QTL很少共定位；早期成熟阶段表达的QTL较多，其次是晚期和中期。20个加性QTL在两年中稳定表达，可能在不同环境下种子活力的建立中发挥重要作用。通过将这些稳定表达的加性QTL的染色体位置与先前鉴定的位置进行比较，种子活力QTL区域可能与粒型、低温发芽能力和种子休眠的QTL区域重合；而5个加性QTL可能代表新基因。利用4个选定的RIL预测了3个用于RIL群体发育的种子活力杂交组合；每个组合可聚合19个优良等位基因。
