水稻染色体片段代换系对氮、磷胁迫反应差异及其QTL分析

利用来源于9311(籼稻)与日本晴(粳稻)杂交后代衍生的遗传背景为9311的染色体片段代换系群体，分析其在大田正常、低氮和低磷条件下的单株有效穗和单株产量的差异。结果表明，低磷、低氮胁迫对单株有效穗和单株产量影响较大。代换系对低磷和低氮的反应存在明显差异。在低氮(磷)水平下共检测到26个单株有效穗和单株产量片段或QTL，以及12个相对单株有效穗和相对单株产量QTL。源于日本晴的等位基因均呈减效作用。低磷和低氮下共同检测到5个导入片段影响单株有效穗或单株产量。而大部分(约81%)QTL只在单胁迫处理下被检测到。表明水稻对磷胁迫和氮胁迫的反应既存在不同的遗传基础，也存在共同的遗传机制。

Quantitative Trait Loci Analysis of Responses to Nitrogen and Phosphorus Deficiency in Rice Chromosomal Segment Substitution Lines

Tolerance to low nitrogen and low phosphorus conditions is a highly desired characteristic for sustainable crop production. In this study, a set of 125 chromosome segment substitution lines (CSSL), each containing a single or few introgression segments from a japonica cv. Nipponbare with the genetic background of an indica cv. 9311, were evaluated using augmented design under the field experiment with normal, low nitrogen (N0), and low phosphorus (P0) conditions. The grain yield and panicle number per plant were measured for each CSSL, and their relative values based on N0 or P0 and normal conditions were considered as the measurement for tolerance to low soil nutrient. The results showed that both the N0 and P0 conditions had strong negative effect on yield and panicle number, and there were different responses among the CSSLs to the stresses, and the relative traits had a significant negative correlation with the traits under the normal condition. 9311 showed better tolerance to low nutrient conditions than Nipponbare. A total of 38 chromosomal regions or quantitative trait loci (QTLs) all with negative allelic effects from Nipponbare were detected for the measured traits under the nitrogen and the phosphorus stresses, of those 26 QTLs were for the yield and panicle number, 12 QTLs for the relative traits. Five chromosomal regions were identified in common under both the stresses, while most QTLs (81%) were specifically detected only in low nitrogen or phosphorus condition. Such different QTLs suggest that the responses to limiting nitrogen and phosphorus conditions are regulated by different sets of genes in rice. Most QTLs for the relative traits were co-localized with those for the yield and the panicle number under either nitrogen or phosphorus stresses, indicating that the tolerance QTLs may be involved in nitrogen and phosphorus uptake or assimilation pathway in rice.