Locatelli Ana B, Federizzi Luiz C, Milach Sandra C K, Wight Charlene P, Molnar Stephen J, Chapados Julie T, Tinker Nicholas A
Federal University of Rio Grande do Sul, Departamento de Plantas de Lavoura, Caixa postal 15100, CEP 91.501-970, Porto Alegre, RS, Brazil.
Genome. 2006 Dec;49(12):1528-38. doi: 10.1139/g06-108.
Flowering time (or days to heading) is an important characteristic in crop plants that affects adaptation to cropping cycles and growing seasons. The objectives of this study were to identify molecular markers associated with flowering time in 3 oat populations developed from Brazilian oat varieties, and to compare their map locations with those of other loci that might influence flowering time. Flowering time was studied in recombinant inbred lines from 3 hexaploid oat populations: UFRGS 8 x Pc68/5Starter; UFRGS 881971 x Pc68/5Starter; and UFRGS 8 x UFRGS 930605. Bulked segregant analysis, using amplified fragment length polymorphism, was followed by selective mapping in each population and in a reference population, 'Kanota' x 'Ogle' (KxO). One quantitative trait locus (QTL) with major effects on flowering time was identified in each cross. Comparative mapping showed that a major QTL, with earliness alleles originating from UFRGS 8 and UFRGS 881971, is in a region with close homology to KxO linkage group 17 and to a locus that reportedly confers day-length insensitivity in oat (Di1). This is the first report to identify the map location of the Di1 locus, and putatively confirm the presence of Di1 alleles in new germplasm. Further comparative mapping and the alignment of mapped oat markers with the sequenced rice genome suggest that this QTL and (or) Di1 is orthologous to the Hd1 locus in rice and the CONSTANS gene in Arabidopsis and other species. A different QTL with major effects segregated in the UFRGS 8 x UFRGS 930605 cross, where the early-flowering allele for Di1 was probably fixed. Two additional QTLs with smaller effects were identified in the UFRGS 8 x Pc68/5*Starter population. These results suggest that the Brazilian oat line UFRGS 8 contains an optimal set of alleles conditioning earliness under the short-day conditions of the Brazilian winter growing season, and that molecular selection could be used to introgress these alleles into other breeding material.
开花时间（或抽穗天数）是作物的一个重要特征，它影响着对种植周期和生长季节的适应性。本研究的目的是在由巴西燕麦品种培育的3个燕麦群体中鉴定与开花时间相关的分子标记，并将它们的图谱位置与其他可能影响开花时间的位点的图谱位置进行比较。在来自3个六倍体燕麦群体的重组自交系中研究了开花时间：UFRGS 8×Pc68/5Starter；UFRGS 881971×Pc68/5Starter；以及UFRGS 8×UFRGS 930605。采用扩增片段长度多态性进行混合分离分析，随后在每个群体以及一个参考群体“Kanota”דOgle”（KxO）中进行选择性作图。在每个杂交组合中都鉴定出了一个对开花时间有主要影响的数量性状位点（QTL）。比较作图表明，一个主要的QTL，其早熟等位基因源自UFRGS 8和UFRGS 881971，位于与KxO连锁群17以及一个据报道赋予燕麦日长不敏感性的位点（Di1）具有紧密同源性的区域。这是首次报道确定Di1位点的图谱位置，并推定确认新种质中存在Di1等位基因。进一步的比较作图以及将定位的燕麦标记与已测序的水稻基因组进行比对表明，这个QTL和（或）Di1与水稻中的Hd1位点以及拟南芥和其他物种中的CONSTANS基因是直系同源的。在UFRGS 8×UFRGS 930605杂交组合中分离出了一个具有主要影响的不同QTL，其中Di1的早花等位基因可能是固定的。在UFRGS 8×Pc68/5*Starter群体中还鉴定出了另外两个影响较小的QTL。这些结果表明，巴西燕麦品系UFRGS 8包含一组在巴西冬季生长季节的短日条件下调节早熟的最佳等位基因，并且分子选择可用于将这些等位基因导入其他育种材料中。
