Analysis of diversity and linkage disequilibrium along chromosome 3B of bread wheat (Triticum aestivum L.)
Analysis of diversity and linkage disequilibrium along chromosome 3B of bread wheat (Triticum aestivum L.)
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DOI：
10.1007/s00122-009-1153-8
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发表时间：
2009-11-01
影响因子：
5.4
通讯作者：
Balfourier, Francois
中科院分区：
文献类型：
--
作者：
Horvath, Aniko;Didier, Audrey;Balfourier, Francois
利用微卫星（SSR）标记和多样性阵列技术（Diversity Arrays），对来源于7个现代小麦品种系谱的高多态性核心种质和窄基育种材料进行了分析，以比较3B染色体上的遗传多样性指数和沿着连锁不平衡（LD）模式。在核心种质中可以鉴定出五个祖先基因库，表明其具有很强的地理结构（西北欧、东南欧、CIMMYT-ICARDA组、亚洲、尼泊尔）。育种材料显示出时间结构，对应于不同时期的育种计划[老品种（从老地方品种到1919年），半现代品种（1920-1959年），现代品种（1960-2006年）]。基本统计数据显示，核心种质的遗传多样性高于育种材料，表明后者的选择压力更大。更一般地，染色体3B具有比整个B基因组更低的多样性。LD在所有研究材料中均较弱。在地理群体中，CIMMYT-ICARDA库呈现出与亚洲加入相反的最长范围LD。在育种材料中，LD从老品种到现代品种逐渐增加。7个现代品种的基因被发现是不同的，大多数标记对显着LD观察亚历山大和Koreli品种之间的基因，表明一个重要的近交效应。在低遗传距离（0-5 cM），育种材料具有较高的LD比核心收集，但在全球范围内，这两种材料在所有类别中具有相似的值。显著LD的标记对通常在染色体3B的两臂的着丝粒周围和短臂的远端位置观察到。
A highly polymorphic core collection of bread wheat and a more narrow-based breeding material, gathered from pedigrees of seven modern cultivars, was analysed in order to compare genetic diversity indices and linkage disequilibrium (LD) patterns along the chromosome 3B with microsatellite (SSR) and Diversity Arrays Technology markers. Five ancestral gene pools could be identified within the core collection, indicating a strong geographical structure (Northwest Europe, Southeast Europe, CIMMYT-ICARDA group, Asia, Nepal). The breeding material showed a temporal structure, corresponding to different periods of breeding programmes [old varieties (from old landraces to 1919), semi-modern varieties (1920-1959), modern varieties (1960-2006)]. Basic statistics showed a higher genetic diversity in the core collection than in the breeding material, indicating a stronger selection pressure in this latter material. More generally, the chromosome 3B had a lower diversity than the whole B-genome. LD was weak in all studied materials. Amongst geographical groups, the CIMMYT-ICARDA pool presented the longest ranged LD in contrast to Asian accessions. In the breeding material, LD increased from old cultivars to modern varieties. Genitors of seven modern cultivars were found to be different; most marker pairs in significant LD were observed amongst genitors of Alexandre and Koreli varieties, indicating an important inbreeding effect. At low genetic distances (0-5 cM), the breeding material had higher LD than the core collection, but globally the two materials had similar values in all classes. Marker pairs in significant LD are generally observed around the centromere in both arms and at distal position on the short arm of the chromosome 3B.