Ha Quynh T, Moe Sandar, Reyes Vincent Pamugas, Doi Kazuyuki, Miura Kotaro, Mizushima Mio, Maeno Akiteru, Tsuda Katsutoshi, Nagai Keisuke, Ashikari Motoyuki
Department of Plant Production Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furocho, Chikusa, Nagoya, Aichi 464-8601, Japan.
Faculty of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-cho, Yoshida-gun, Fukui 910-1195, Japan.
Breed Sci. 2024 Dec;74(5):443-453. doi: 10.1270/jsbbs.24036. Epub 2024 Dec 3.
Stem length is a crucial agronomic trait in rice breeding. The short stature of rice dwarf mutants is caused by shortening of internodes, resulting in five distinct internode elongation patterns: dn, dm, d6, nl and sh. Several genetic studies have been conducted; however, the genetic mechanisms underlying these internode elongation patterns remain unclear. In this study, we examined two Daikoku dwarf () mutants, T65() and Kin(), which display contrasting internode elongation phenotypes. Anatomical observation revealed that T65() exhibits a dm-type internode elongation pattern due to the lack of the second internode counted from the top, while Kin() shows a dn-type pattern with a relatively elongated second internode. To identify the genetic factors influencing these phenotypes, we conducted a quantitative trait locus (QTL) analysis using two F populations derived from reciprocal crosses between them. The QTL analysis showed that the second internode length is regulated by three QTLs on chromosomes 4, 5, and 6. Epistatic effects were observed through the analysis of F progenies, indicating that the combination of Kin() alleles at these QTLs is associated with an increased second internode length. Furthermore, specific combinations of alleles result in varying degrees of elongation in the second internode, significantly impacting the internode elongation pattern. These findings contribute to a deeper understanding of the genetic factors influencing the internode elongation patterns in rice.
茎长是水稻育种中的一个关键农艺性状。水稻矮化突变体的矮化株型是由节间缩短引起的，导致了五种不同的节间伸长模式：dn、dm、d6、nl和sh。已经进行了多项遗传学研究；然而，这些节间伸长模式背后的遗传机制仍不清楚。在本研究中，我们研究了两个大宫矮秆（Daikoku dwarf）突变体，T65（）和Kin（），它们表现出相反的节间伸长表型。解剖学观察表明，T65（）由于缺少从顶部数的第二节间而表现出dm型节间伸长模式，而Kin（）表现出dn型模式，其第二节间相对伸长。为了确定影响这些表型的遗传因素，我们使用了由它们之间的正反交产生的两个F群体进行了数量性状位点（QTL）分析。QTL分析表明，第二节间长度受第4、5和6号染色体上的三个QTL调控。通过对F后代的分析观察到上位性效应，表明这些QTL上Kin（）等位基因的组合与第二节间长度增加有关。此外，等位基因的特定组合导致第二节间不同程度的伸长，显著影响节间伸长模式。这些发现有助于更深入地了解影响水稻节间伸长模式的遗传因素。
