QTL mapping with near-isogenic lines in maize
QTL mapping with near-isogenic lines in maize
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DOI：
10.1007/s00122-007-0512-6
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发表时间：
2007-05-01
影响因子：
5.4
通讯作者：
Holland, J. B.
中科院分区：
文献类型：
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作者：
Szalma, S. J.;Hostert, B. M.;Holland, J. B.
利用标记辅助选择技术，建立了89个玉米近等基因系。利用限制性片段长度多态性位点鉴定的19个基因组区域代表了所有10条玉米染色体的部分，并通过3代回交将这些区域与B73遗传背景进行了渐渗。在另外128个简单序列重复位点上对NILs进行基因分型，以估计基因渗入的大小和背景渗入的数量。Tx303基因渗入的大小在10 ~ 150 cM之间，平均为60 cM。在所有NILs中，89%的Tx303基因组在靶向和背景渗入中都有体现。背景渗入的平均比例为2.5%（范围0 ~ 15%），显著低于无标记辅助选择的回交三代株系的9.4%。在2年的重复田间评价中种植了NILs，以绘制开花时间性状的qtl。在相同的环境下，将每一个无亲缘关系的测试组合与无亲缘关系的自交系Mo17进行平行实验，绘制无亲缘关系测试组合的qtl图谱。在两种环境下，在自交系和杂交系中均检测到影响花期、出丝日和花丝间隔的qtl。干旱胁迫下的测试环境差异显著，不同环境下检测到的qtl也不同。此外，在自交系中检测到的qtl与杂交种中检测到的qtl存在典型差异，这表明开花时间的遗传复杂性。NILs可以作为玉米育种家和遗传学家宝贵的遗传作图资源。
A set of 89 near-isogenic lines (NILs) of maize was created using marker-assisted selection. Nineteen genomic regions, identified by restriction fragment length polymorphism loci and chosen to represent portions of all ten maize chromosomes, were introgressed by backcrossing three generations from donor line Tx303 into the B73 genetic background. NILs were genotyped at an additional 128 simple sequence repeat loci to estimate the size of introgressions and the amount of background introgression. Tx303 introgressions ranged in size from 10 to 150 cM, with an average of 60 cM. Across all NILs, 89% of the Tx303 genome is represented in targeted and background introgressions. The average proportion of background introgression was 2.5% (range 0-15%), significantly lower than the expected value of 9.4% for third backcross generation lines developed without marker-assisted selection. The NILs were grown in replicated field evaluations in two years to map QTLs for flowering time traits. A parallel experiment of testcrosses of each NIL to the unrelated inbred, Mo17, was conducted in the same environments to map QTLs in NIL testcross hybrids. QTLs affecting days to anthesis, days to silking, and anthesis-silk interval were detected in both inbreds and hybrids in both environments. The testing environments differed dramatically for drought stress, and different sets of QTLs were detected across environments. Furthermore, QTLs detected in inbreds were typically different from QTLs detected in hybrids, demonstrating the genetic complexity of flowering time. NILs can serve as a valuable genetic mapping resource for maize breeders and geneticists.