Nonoue Y, Fujino K, Hirayama Y, Yamanouchi U, Lin S Y, Yano M
Institute of Society for Techno-innovation of Agriculture, Forestry and Fisheries, 446-1 Kamiyokoba, Tsukuba, Ibaraki 305-0854, Japan.
Theor Appl Genet. 2008 Mar;116(5):715-22. doi: 10.1007/s00122-007-0704-0. Epub 2008 Jan 9.
To clarify the genetic basis of extremely early heading in rice, we conducted quantitative trait locus (QTL) analyses using F2 populations from two genetically wide cross combinations, Hayamasari/Kasalath (HaF2) and Hoshinoyume/Kasalath (HoF2). Hayamasari and Hoshinoyume are extremely early-heading japonica cultivars. Photoperiod sensitivity is completely lost in Hayamasari and weak in Hoshinoyume. Three QTLs, QTL(chr6), QTL(chr7), and QTL(chr8), for days-to-heading (DTH) in HaF2 were detected on chromosomes 6, 7, and 8, respectively, and QTL(chr6) and QTL(chr7) were detected in HoF2. On the basis of the chromosomal locations, QTL(chr6), QTL(chr7), and QTL(chr8) may be likely to be Hd1, Hd4, and Hd5, respectively, which had been detected previously as QTLs for DTH in an F2 population of NipponbarexKasalath. Alleles of QTL(chr7) decreased DTH dramatically in both Hayamasari and Hoshinoyume, suggesting that QTL(chr7) has a major role in determining extremely early heading. In addition, allele-specific interactions were detected between QTL(chr6), QTL(chr7) and QTL(chr8). This result suggests that not only allelic differences but also epistatic interactions contribute to extremely early heading. QTL(chr8) was detected in HaF2, but not in HoF2, suggesting that it determines the difference in DTH between Hayamasari and Hoshinoyume. A major QTL was also detected in the region of QTL(chr8) in QTL analysis using an F2 population of HayamasarixHoshinoyume. This result supports the idea that QTL(chr8) is a major factor that determines the difference in DTH between Hayamasari and Hoshinoyume, and is involved in photoperiod sensitivity.
为了阐明水稻极早熟的遗传基础，我们利用两个遗传差异较大的杂交组合（滨锦/卡萨拉思（HaF2）和星之梦/卡萨拉思（HoF2））的F2群体进行了数量性状基因座（QTL）分析。滨锦和星之梦是极早熟的粳稻品种。滨锦完全丧失了光周期敏感性，星之梦的光周期敏感性较弱。在HaF2中，分别在第6、7和8号染色体上检测到了控制抽穗天数（DTH）的3个QTL，即QTL（chr6）、QTL（chr7）和QTL（chr8），在HoF2中检测到了QTL（chr6）和QTL（chr7）。根据染色体定位，QTL（chr6）、QTL（chr7）和QTL（chr8）可能分别是Hd1、Hd4和Hd5，它们先前在日本晴×卡萨拉思的F2群体中被检测为DTH的QTL。QTL（chr7）的等位基因在滨锦和星之梦中均显著降低了DTH，这表明QTL（chr7）在决定极早熟方面起主要作用。此外，还检测到QTL（chr陆、QTL（chr7）和QTL（chr8）之间的等位基因特异性互作。这一结果表明，不仅等位基因差异，而且上位性互作也对极早熟有贡献。QTL（chr8）在HaF2中被检测到，但在HoF2中未被检测到，这表明它决定了滨锦和星之梦之间DTH的差异。在利用滨锦×星之梦的F2群体进行的QTL分析中，在QTL（chr8）区域也检测到了一个主效QTL。这一结果支持了QTL（chr8）是决定滨锦和星之梦之间DTH差异的主要因素且与光周期敏感性有关的观点。
