Huang Zheng, Yu Ting, Su Li, Yu Si-Bin, Zhang Zhi-Hong, Zhu Ying-Guo
Key Laboratory of the Education Ministry of China for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Yi Chuan Xue Bao. 2004 Jun;31(6):596-603.
Seedling vigor is important for optimum stand establishment in rice cropping. In this paper,a set of 264 F12 recombinant inbred lines (RILs) derived by single seed descent from a cross between Lemont (japonica) and Teqing (indica) was phenotyped for three seedling vigor related traits, including seed germination rate (GR), seedling shoot length and dry weight by the rolled paper towel tests. The phenotype data and a linkage map consisting of 198 DNA markers were combined to map quantitative trait loci (QTL) for seedling vigor by using a computer program QTLMapper1.0. A total of 13 putative main-effect QTL were detected. All of these QTL had much smaller effects on the traits with a mean R2 of 6.2%, ranging from 2.9% to 12.7%. As for digenic interaction, 18 pairs of epistatic loci with R2 > or = 5% were resolved with a mean R2 of 6.9% ,ranging from 5.1% to 11.8%, which was slightly larger than that of the main-effect QTL identified for the traits. The majority of the main-effect and epistatic loci detected for seedling vigor related traits were clustered in a few chromosome regions. Together, seven such chromosome regions (CRs), each with three or more seedling vigor main-effect and epistatic loci, were found to be highly associated with seedling vigor. These CRs can be classified into three types, i.e. M-CRs, E-CRs and ME-CRs. For some CRs just like CR(SV-6), the QTL within one CR were found to interact simultaneously with QTL within more than one other CRs to affect different seedling vigor related traits. The above results revealed that seedling vigor in rice is controlled by many loci, most of which have relatively small effects. Comparatively, epistasis as a genetic factor would be more important than main-effects of QTL for seedling vigor in rice. Nevertheless, the effects of the QTL are still large enough to be detected and in fact several chromosome regions were found to be highly associated with seedling vigor in very different populations as compared with previous studies. Molecular tagging of favorable alleles and marker-aided selection strategy may, therefore, be a promising approach to the improvement of rice seedling vigor.
秧苗活力对于水稻种植中实现最佳立苗很重要。本文通过单粒传法从Lemont(粳稻)和特青(籼稻)杂交后代中获得了一组264个F12重组自交系(RILs),通过卷纸毛巾试验对与秧苗活力相关的三个性状进行了表型分析,包括种子发芽率(GR)、秧苗地上部长度和干重。利用计算机程序QTLMapper1.0将表型数据和由198个DNA标记组成的连锁图谱相结合,对秧苗活力的数量性状位点(QTL)进行定位。共检测到13个推定的主效QTL。所有这些QTL对性状的影响都小得多,平均R2为6.2%,范围从2.9%到12.7%。至于双基因互作,解析出18对上位性位点,R2≥5%,平均R2为6.9%,范围从5.1%到11.8%,略大于为这些性状鉴定出的主效QTL的R2。检测到的与秧苗活力相关性状的大多数主效和上位性位点集中在少数几个染色体区域。总共发现了七个这样的染色体区域(CRs),每个区域有三个或更多的秧苗活力主效和上位性位点,这些区域与秧苗活力高度相关。这些CRs可分为三种类型,即M-CRs、E-CRs和ME-CRs。对于某些CRs,如CR(SV-6),发现一个CR内的QTL与一个以上其他CR内的QTL同时相互作用,以影响不同的秧苗活力相关性状。上述结果表明,水稻的秧苗活力受许多位点控制,其中大多数位点的效应相对较小。相比之下,上位性作为一个遗传因素,对水稻秧苗活力而言比QTL的主效应更重要。然而,QTL的效应仍然足够大,可以被检测到,事实上,与以前的研究相比,在非常不同的群体中发现了几个染色体区域与秧苗活力高度相关。因此,有利等位基因的分子标记和标记辅助选择策略可能是提高水稻秧苗活力的一种有前途的方法。