氮胁迫和非胁迫条件下玉米不同时期叶绿素含量的QTL分析

QTL analysis of chlorophyll content of maize under N-stress and no N-stress at different development stages

以优良玉米杂交种农大108的203个F2:3家系为材料,构建了包含189个SSR标记的遗传连锁图谱,利用复合区间作图法,在施氮(+N)和不施氮(-N)情况下,对玉米不同发育时期的叶绿素含量进行了QTL(数量性状座位)分析。结果表明:在-N和+N条件下,亲本许178的5个时期叶绿素(SPAD)均值分别为54.12和55.76,比黄C分别高1.80和2.40;而F2:3家系的SPAD均值分别达55.6和58.32,高于双亲的中亲值;同时,在+N情况下,叶绿素含量变异范围相对较小,说明氮胁迫对玉米叶绿素含量的变化具有一定影响。-N和+N情况下,在玉米喇叭口期、散粉期、灌浆初期、灌浆中期和灌浆后期分别检测到2、2、1、3、1个和2、2、2、7、1个叶绿素含量的非条件QTL,可分别解释对应时期叶绿素含量表型总变异的22.75%、22.93%、19.77%、49.87%、12.79%和16.95%、23.49%、19.38%、84.56%、13.38%。在-N和+N情况下,喇叭口期至散粉期、灌浆中期至灌浆后期和喇叭口期至散粉期、散粉期至灌浆初期各检测到1个条件QTL,可分别解释叶绿素含量表型变异的12.90%、25.51%和5.98%、26.67%。叶绿素含量的QTL表达存在时空性,其中qchl4和qchl5b在整个生育时期均能检测到,是玉米生长发育所必需的两个QTL。

In this study,the unconditional and conditional QTL（Quantitative trait locus） analysis for chlorophyll contents（CC） at different development stages of maize were detected under N input（＋ N） and N stress（N）,using the composite interval mapping method with a 203 F2： 3 population derived from an elite maize hybrid cultivar： Nongda108（Huang C ×Xu178）,and a molecular linkage maps including 189 SSR markers.The results showed that the mean CC at the five development stages（bell stage,BS;florescence stage,FS;early grain filling stage,EGFS;mid-grain filling stage,MGFS;later grain filling stage,LGFS） for parent Xu178 under-N and ＋ N conditions were 54.12 and 55.76,and there were 1.80 and 2.40 higher than another parent Huang C,respectively.The average CC for the F2∶3 populations were 55.6 and 58.32,higher than the mean of their parents, and the variance range of CC in ＋ N was smaller than that ofN.These results implied that the variance ranges for CC were affected by-N stress in some degree.Under-N and ＋ N conditions,2,2,1,3,1 and/or 2,2,2,7,1 unconditional QTL for CC were detected at the five development stages respectively,and the accumulative contribution of the detected QTL could explain 22.75%,22.93%,19.77%, 49.87%,12.79% and/or 16.95%,23.49%,19.38%,84.56 %,13.38% phenotypic variances of CC,respectively.There was one conditional QTL identified for periods from BS to FS,from MGFS to LGFS and/or from BS to FS,and from FS to EGFS underN and ＋ N conditions,these could explain 12.90%,25.51% and/or 15.98%,26.67% phenotypic variances of CC for each period,respectively.There were different spatiotemporal patterns for QTL expression of CC,especially for qchl4 and qchl5b, which are the two major QTLs in maize development.