利用水稻MAGIC群体关联定位抽穗期和株高QTL

利用多亲本高代互交系(multi-parent advanced generation inter-cross,MAGIC)群体(DC1、DC2和8way)及其复合群体DC12(DC1+DC2)和RMPRIL(DC1+DC2+8way)进行关联分析定位水稻抽穗期和株高QTL。2015年和2016年分别在江西和深圳收集3个MAGIC群体抽穗期数据,2016年在两地收集株高数据,结合Rice 55K SNP芯片进行基因分型,利用关联分析方法检测到3个影响抽穗期的主效QTL(q HD3、q HD6和q HD8),分别位于第3、第6和第8染色体,且分别与已知抽穗期基因DTH3、Hd3a和Ghd8在同一区域。检测到5个影响株高的QTL(q PH1.1、q PH1.2、q PH1.3、q PH4和q PH6),其中q PH1.1和q PH1.2位于已知基因Psd1和sd1附近,其余3个QTL为影响株高的新位点,但仅在1个群体和单个环境下被检测到,QTL表达受遗传背景和环境影响大。不同MAGIC群体定位抽穗期和株高的效果不同,在8亲本MAGIC群体8way及复合群体DC12和RMPRIL分别检测到5、5和6个抽穗期和株高QTL,明显多于4亲本群体DC1的2个和DC2的4个,而且作图的精度更高,表现在定位到的QTL显著水平高和与已知基因距离更近,尤其是复合群体的联合分析(如DC12和RMPRIL)的作图优势更为明显。

Mapping of QTL for Heading Date and Plant Height Using MAGIC Populations of Rice

Association analysis was performed to map QTL for heading date (HD) and plant height (PH) using three multi-parent advanced generation inter-cross (MAGIC) populations including two four-parent- and one eight-parent- derived populations (DC1, DC2 and 8way), and their composite populations (DC12=DC1+DC2, RMPRIL=DC12+8way) derived from eight elite indica lines. Using the phenotypic data of HD collected in the two sites (Jiangxi and Shenzhen) across two years (2015 and 2016), PH collected in the two sites (Jiangxi and Shenzhen) in 2016, and SNP genotypic data of Rice 55K SNP chip, three HD QTLs, qHD3, qHD6 and qHD8 were identified in the same regions of DTH3, Hd3a and Ghd8, respectively. And five PH QTLs (qPH1.1, qPH1.2, qPH1.3, qPH4 and qPH6) were also identified, of which qPH1.1 and qPH1.2 were located in the adjacent regions of Psd1 and sd1. The other three PH QTLs were new loci which were detected only in one population under one environment showing larger effects of genetic background and environment. Different MAGIC populations had different mapping effects for HD and PH. Using eight-parent-derived populations such as 8way, DC12 and RMPRIL not only detected more HD and PH QTL (5, 5, and 6) but also had higher mapping resolution than four parents-derived populations such as DC1 and DC2 (2 and 4), showing an obvious advantage in two aspects of QTL mapping: highly significant level and closed to known genes. Especially, joint analyses of different populations such as DC12 and RMPRIL had significant advantage in QTL mapping. The results laid the foundation for mining the favorable allele of heading date and plant height, and provided materials and information of molecular breeding.