Krishnappa Gopalareddy, Singh Anju Mahendru, Chaudhary Swati, Ahlawat Arvind Kumar, Singh Santosh Kumar, Shukla Ram Bihari, Jaiswal Jai Prakash, Singh Gyanendra Pratap, Solanki Ishwar Singh
Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India.
Division of Crop Improvement, ICAR- Indian Institute of Wheat & Barley Research, Karnal, Haryana, India.
PLoS One. 2017 Apr 6;12(4):e0174972. doi: 10.1371/journal.pone.0174972. eCollection 2017.
Genomic regions responsible for accumulation of grain iron concentration (Fe), grain zinc concentration (Zn), grain protein content (PC) and thousand kernel weight (TKW) were investigated in 286 recombinant inbred lines (RILs) derived from a cross between an old Indian wheat variety WH542 and a synthetic derivative (Triticum dicoccon PI94624/Aegilops squarrosa [409]//BCN). RILs were grown in six environments and evaluated for Fe, Zn, PC, and TKW. The population showed the continuous distribution for all the four traits, that for pooled Fe and PC was near normal, whereas, for pooled Zn, RILs exhibited positively skewed distribution. A genetic map spanning 2155.3cM was constructed using microsatellite markers covering the 21 chromosomes and used for QTL analysis. 16 quantitative trait loci (QTL) were identified in this study. Four QTLs (QGFe.iari-2A, QGFe.iari-5A, QGFe.iari-7A and QGFe.iari-7B) for Fe, five QTLs (QGZn.iari-2A, QGZn.iari-4A, QGZn.iari-5A, QGZn.iari-7A and QGZn.iari-7B) for Zn, two QTLs (QGpc.iari-2A and QGpc.iari-3A) for PC, and five QTLs (QTkw.iari-1A, QTkw.iari-2A, QTkw.iari-2B, QTkw.iari-5B and QTkw.iari-7A) for TKW were identified. The QTLs together explained 20.0%, 32.0%, 24.1% and 32.3% phenotypic variation, respectively, for Fe, Zn, PC and TKW. QGpc.iari-2A was consistently expressed in all the six environments, whereas, QGFe.iari-7B and QGZn.iari-2A were identified in two environments each apart from pooled mean. QTkw.iari-2A and QTkw.iari-7A, respectively, were identified in four and three environments apart from pooled mean. A common region in the interval of Xgwm359-Xwmc407 on chromosome 2A was associated with Fe, Zn, and PC. One more QTL for TKW was identified on chromosome 2A but in a different chromosomal region (Xgwm382-Xgwm359). Two more regions on 5A (Xgwm126-Xgwm595) and 7A (Xbarc49-Xwmc525) were found to be associated with both Fe and Zn. A QTL for TKW was identified (Xwmc525-Xbarc222) in a different chromosomal region on the same chromosome (7A). This reflects at least a partly common genetic basis for the four traits. It is concluded that fine mapping of the regions of the three chromosomes of A genome involved in determining the accumulation of Fe, Zn, PC, and TKW in this mapping population may be rewarding.
在由古老的印度小麦品种WH542与一个合成衍生物（二粒小麦PI94624/粗山羊草[409]//BCN）杂交产生的286个重组自交系（RIL）中，研究了负责籽粒铁浓度（Fe）、籽粒锌浓度（Zn）、籽粒蛋白质含量（PC）和千粒重（TKW）积累的基因组区域。RIL在六种环境中种植，并对Fe、Zn、PC和TKW进行评估。该群体所有四个性状均呈现连续分布，合并后的Fe和PC接近正态分布，而合并后的Zn，RIL呈现正偏态分布。使用覆盖21条染色体的微卫星标记构建了一个跨度为2155.3cM的遗传图谱，并用于QTL分析。本研究共鉴定出16个数量性状位点（QTL）。其中，4个Fe的QTL（QGFe.iari - 2A、QGFe.iari - 5A、QGFe.iari - 7A和QGFe.iari - 7B），5个Zn的QTL（QGZn.iari - 2A、QGZn.iari - 4A、QGZn.iari - 5A、QGZn.iari - 7A和QGZn.iari - 7B），2个PC的QTL（QGpc.iari - 2A和QGpc.iari - 3A），以及5个TKW的QTL（QTkw.iari - 1A、QTkw.iari - 2A、QTkw.iari - 2B、QTkw.iari - 5B和QTkw.iari - 7A）。这些QTL分别解释了Fe、Zn、PC和TKW表型变异的20.0%、32.0%、24.1%和32.3%。QGpc.iari - 2A在所有六种环境中均持续表达，而QGFe.iari - 7B和QGZn.iari - 2A除合并均值外，分别在两种环境中被鉴定出。QTkw.iari - 2A和QTkw.iari - 7A除合并均值外，分别在四种和三种环境中被鉴定出。2A染色体上Xgwm359 - Xwmc407区间的一个共同区域与Fe、Zn和PC相关。在2A染色体上另一个不同的染色体区域（Xgwm382 - Xgwm359）鉴定出一个TKW的QTL。在5A（Xgwm126 - Xgwm595）和7A（Xbarc49 - Xwmc525）上还发现另外两个区域与Fe和Zn均相关。在同一染色体（7A）的一个不同染色体区域（Xwmc525 - Xbarc222）鉴定出一个TKW的QTL。这反映了这四个性状至少部分存在共同的遗传基础。得出结论，对该作图群体中涉及决定Fe、Zn、PC和TKW积累的A基因组三条染色体区域进行精细定位可能会有所收获。
