水稻染色体片段代换系对氮反应的QTL分析

QTL Identification for Nitrogen Responses in Rice Chromosomal Segment Substitution Lines

利用来源于93-11(受体)和日本晴(供体)构建的染色体片段代换系,采用盆栽试验分析其在两种氮水平下产量相关性状的差异,包括株高、每穗实粒数、单株产量、根干重、地上部干物重以及氮素利用效率等。结果表明,与正常条件相比,低氮胁迫条件下代换系的单株产量与生物学产量显著降低。两种氮水平下共定位到54个QTLs,其中仅有6个在两种氮水平下同时检测到,说明水稻对不同氮肥反应由不同的基因调控。定位到5个氮肥农学利用效率QTLs,其中,第6染色体的qNAE6解释表型变异较大(14%)。同时,我们还发现存在一些QTL区域同时影响多个性状,如第2染色体RM2634区域,第6染色体RM510-RM225区域,第10染色体RM228和第11染色体RM536区域,暗示其可能是一因多效或紧密连锁的基因的效应。该结果将为鉴定分析氮利用相关基因以及氮高效育种提供一定试验依据。

In order to understand the genetic basis of nitrogen use efficiency in rice,a set of 127 chromosomal segment substitution lines（CSSLs） from the cross between indica cv.93-11 and japonica cv.Nipponbare were planted under low and normal nitrogen conditions in pot experiments.Six biomass and yield related traits including plant height,grain number per panicle,grain yield per plant,dry weight of root and shoot,and nitrogen agronomic use efficiency were investigated at maturity stage.Significant reduction in the yield per plant and the biomass traits were observed under low nitrogen condition in comparison with the normal condition.A total of 54 quantitative trait loci（QTL） were identified under these two nitrogen treatments.The majority of QTL were detected in either low or normal nitrogen condition,while only 6 QTL were detected in both nitrogen conditions,suggesting that different sets of genes response to different nitrogen levels.Five QTL of nitrogen agronomic use efficiency were detected,of which qNAE6 explained 14% of the total phenotypic variation.In addition,several QTL clusters were identified located on different chromosome regions such as nearby RM2634 on chromosome 2,RM510-RM225 on chromosome 6,nearby RM228 on chromosome 10 and RM536 on chromosome 11,indicating that it may be caused by pleiotropy or close linkage of genes.These results will provide useful information for fine mapping of genes underlying nitrogen use efficiency in rice.