State Key Lab of Rice Biology, International Atomic Energy Agency Collaborating Center, Zhejiang University, Hangzhou, People's Republic of China.
PLoS One. 2012;7(1):e29350. doi: 10.1371/journal.pone.0029350. Epub 2012 Jan 23.
Harvest index is a measure of success in partitioning assimilated photosynthate. An improvement of harvest index means an increase in the economic portion of the plant. Our objective was to identify genetic markers associated with harvest index traits using 203 O. sativa accessions. The phenotyping for 14 traits was conducted in both temperate (Arkansas) and subtropical (Texas) climates and the genotyping used 154 SSRs and an indel marker. Heading, plant height and weight, and panicle length had negative correlations, while seed set and grain weight/panicle had positive correlations with harvest index across both locations. Subsequent genetic diversity and population structure analyses identified five groups in this collection, which corresponded to their geographic origins. Model comparisons revealed that different dimensions of principal components analysis (PCA) affected harvest index traits for mapping accuracy, and kinship did not help. In total, 36 markers in Arkansas and 28 markers in Texas were identified to be significantly associated with harvest index traits. Seven and two markers were consistently associated with two or more harvest index correlated traits in Arkansas and Texas, respectively. Additionally, four markers were constitutively identified at both locations, while 32 and 24 markers were identified specifically in Arkansas and Texas, respectively. Allelic analysis of four constitutive markers demonstrated that allele 253 bp of RM431 had significantly greater effect on decreasing plant height, and 390 bp of RM24011 had the greatest effect on decreasing panicle length across both locations. Many of these identified markers are located either nearby or flanking the regions where the QTLs for harvest index have been reported. Thus, the results from this association mapping study complement and enrich the information from linkage-based QTL studies and will be the basis for improving harvest index directly and indirectly in rice.
收获指数是衡量同化光合产物分配成功的指标。收获指数的提高意味着植物经济部分的增加。我们的目标是使用 203 个 O. sativa 品系，通过关联分析鉴定与收获指数性状相关的遗传标记。在温带（阿肯色州）和亚热带（德克萨斯州）气候下对 14 个性状进行表型分析，并使用 154 个 SSR 和一个插入缺失标记进行基因型分析。抽穗期、株高和重量以及穗长与两个地点的收获指数呈负相关，而结实率和每穗粒重与收获指数呈正相关。随后的遗传多样性和群体结构分析在该群体中确定了五个组，这与它们的地理起源相对应。模型比较表明，主成分分析（PCA）的不同维度对定位准确性有影响，亲缘关系没有帮助。总共在阿肯色州鉴定出 36 个标记，在德克萨斯州鉴定出 28 个标记与收获指数性状显著相关。在阿肯色州和德克萨斯州，分别有 7 个和 2 个标记与两个或更多与收获指数相关的性状始终相关。此外，在两个地点都鉴定出 4 个标记，而在阿肯色州和德克萨斯州分别鉴定出 32 个和 24 个标记。四个组成型标记的等位基因分析表明，RM431 的 253 bp 等位基因对降低株高的影响显著，RM24011 的 390 bp 等位基因对降低两个地点的穗长的影响最大。这些鉴定出的标记中的许多都位于已报道的收获指数 QTL 附近或侧翼。因此，这项关联作图研究的结果补充和丰富了基于连锁的 QTL 研究的信息，并将成为直接和间接提高水稻收获指数的基础。
