Shen Congcong, Chen Kai, Cui Yanru, Chen Jiantao, Mi Xuefei, Zhu Shuangbin, Zhu Yajun, Ali Jauhar, Ye Guoyou, Li Zhikang, Xu Jianlong
Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
Institute of Crop Sciences, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Genet. 2021 Apr 6;12:616428. doi: 10.3389/fgene.2021.616428. eCollection 2021.
Nitrogen is one of the most important nutrients for rice growth and development. Breeding of nitrogen deficiency tolerance (NDT) variety is considered to be the most economic measure to solve the constrain of low nitrogen stress on grain yield in rice. An interconnected breeding (IB) population of 497 lines developed using Huanghuazhan (HHZ) as the recurrent parent and eight elite lines as the donor parents were tested for five traits including grain yield, biomass, harvest index, thousand grain weight, and spikelet fertility under two nitrogen treatments in three growing seasons. Association analysis using 7,388 bins generated by sequencing identified a total of 14, 14, and 12 QTLs for the five traits under low nitrogen (LN), normal nitrogen (NN), and LN/NN conditions, respectively, across three seasons. Favorable alleles were dissected for the 40 QTLs at the 10 NDT regions, and OM1723 was considered as the most important parent with the highest frequency of favorable alleles contributing to NDT-related traits. Six superior lines all showed significantly higher GY in LN environments and similar GY under NN environments except for H10. Substitution mapping using near-isogenic introgression lines delimited the , which was identified on chromosome 2 under LN, NN, and LN/NN conditions into two QTLs, which were located in the two regions of about 200 and 350 kb with different favorable alleles. The bins 16, 1301, 1465, 1486, 3464, and 6249 harbored the QTLs for NDT detected in this study, and the QTLs/genes previously identified for NDT or nitrogen use efficiency (NUE) could be used for enhancing NDT and NUE by marker-assisted selection (MAS).
氮是水稻生长发育最重要的养分之一。培育耐缺氮品种被认为是解决低氮胁迫对水稻产量限制的最经济措施。以黄华占（HHZ）为轮回亲本、8个优良品系为供体亲本构建了一个包含497个株系的互交群体，在三个生长季的两种氮处理条件下，对其产量、生物量、收获指数、千粒重和小穗育性这5个性状进行了测定。利用测序产生的7388个bin进行关联分析，在三个生长季中，分别在低氮（LN）、正常氮（NN）和LN/NN条件下，共鉴定出14个、14个和12个与这5个性状相关的QTL。对10个耐缺氮区域的40个QTL的有利等位基因进行了解析，OM1723被认为是对耐缺氮相关性状贡献有利等位基因频率最高的最重要亲本。除H10外，6个优良株系在低氮环境下均表现出显著更高的产量，在正常氮环境下产量相似。利用近等基因渐渗系进行代换作图，将在LN、NN和LN/NN条件下在第2染色体上鉴定到的一个QTL定位到两个QTL上，它们位于约200 kb和350 kb的两个区域，具有不同的有利等位基因。本研究检测到的耐缺氮QTL位于bin16、1301、1465、1486、3464和6249中，先前鉴定的耐缺氮或氮利用效率（NUE）的QTL/基因可用于通过分子标记辅助选择（MAS）提高耐缺氮性和氮利用效率。
