Phenotypic selection for dormancy introduced a set of adaptive haplotypes from weedy into cultivated rice
Phenotypic selection for dormancy introduced a set of adaptive haplotypes from weedy into cultivated rice
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DOI：
10.1534/genetics.105.043612
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发表时间：
2005-10-01
期刊：
影响因子：
3.3
通讯作者：
Foley, ME
中科院分区：
文献类型：
--
作者：
Gu, XY;Kianian, SF;Foley, ME
种子休眠与破碎、芒色、黑色外壳和红色果皮颜色的关联增强了野生和杂草物种的存活率，但对休眠基因在抗收获前发芽的育种品种中的使用提出了挑战。使用表型选择和循环回交技术将休眠基因从野生杂草稻引入育种系，以确定其效果以及与其他性状的联系。仅针对低发芽极限的五代表型选择同时保留了五个独立 QTL 处的休眠等位基因，包括 qSD12 (R-2 > 50%)，通过全基因组扫描确定它们在两个 BC4F2 群体中的主要和/或上位效应。四个具有中度至小度影响的休眠位点与一到三个相关性状的 QTL/基因位于同一位置。对选择的多位点反应表明，这些休眠基因的作用是累积的，并且通过上位性形成网络，并且该网络可能在杂草进化过程中维持完整的适应性单倍型方面发挥了“庇护”作用。紧密连锁可能会阻止休眠基因用于育种计划。 qSD12 的主要作用使其成为基于图位的克隆的理想靶标，也是赋予收获前发芽抗性的最佳候选者。
Association of seed dormancy with shattering, awn, and black hull and red pericarp colors enhances survival of wild and weedy species, but challenges the use of dormancy genes in breeding varieties resistant to preharvest sprouting. A phenotypic selection and recurrent backcrossing technique was used to introduce dormancy genes from a wild-like weedy rice to a breeding line to determine their effects and linkage with the other traits. Five generations of phenotypic selection alone for low germination extremes simultaneously retained dormancy alleles at five independent QTL, including qSD12 (R-2 > 50%), as determined by genome-wide scanning for their main and/or epistatic effects in two BC4F2 Populations. Four dormancy loci with moderate to small effects colocated with QTL/genes for one to three of the associated traits. Multilocus response to the selection suggests that these dormancy genes are cumulative in effect, as well as networked by epistases, and that the network may have played a "sheltering" role in maintaining intact adaptive haplotypes during the evolution of weeds. Tight linkage may prevent the dormancy genes from being used in breeding programs. The major effect of qSD12 makes it an ideal target for map-based cloning and the best candidate for imparting resistance to preharvest sprouting.