UMR-DAP, CIRAD, Montpellier, France.
BMC Plant Biol. 2010 Jun 28;10:132. doi: 10.1186/1471-2229-10-132.
Cotton fibers (produced by Gossypium species) are the premier natural fibers for textile production. The two tetraploid species, G. barbadense (Gb) and G. hirsutum (Gh), differ significantly in their fiber properties, the former having much longer, finer and stronger fibers that are highly prized. A better understanding of the genetics and underlying biological causes of these differences will aid further improvement of cotton quality through breeding and biotechnology. We evaluated an inter-specific Gh x Gb recombinant inbred line (RIL) population for fiber characteristics in 11 independent experiments under field and glasshouse conditions. Sites were located on 4 continents and 5 countries and some locations were analyzed over multiple years.
The RIL population displayed a large variability for all major fiber traits. QTL analyses were performed on a per-site basis by composite interval mapping. Among the 651 putative QTLs (LOD > 2), 167 had a LOD exceeding permutation based thresholds. Coincidence in QTL location across data sets was assessed for the fiber trait categories strength, elongation, length, length uniformity, fineness/maturity, and color. A meta-analysis of more than a thousand putative QTLs was conducted with MetaQTL software to integrate QTL data from the RIL and 3 backcross populations (from the same parents) and to compare them with the literature. Although the global level of congruence across experiments and populations was generally moderate, the QTL clustering was possible for 30 trait x chromosome combinations (5 traits in 19 different chromosomes) where an effective co-localization of unidirectional (similar sign of additivity) QTLs from at least 5 different data sets was observed. Most consistent meta-clusters were identified for fiber color on chromosomes c6, c8 and c25, fineness on c15, and fiber length on c3.
Meta-analysis provided a reliable means of integrating phenotypic and genetic mapping data across multiple populations and environments for complex fiber traits. The consistent chromosomal regions contributing to fiber quality traits constitute good candidates for the further dissection of the genetic and genomic factors underlying important fiber characteristics, and for marker-assisted selection.
棉花纤维（由棉属物种生产）是纺织生产的主要天然纤维。两个四倍体物种，海岛棉（Gb）和陆地棉（Gh），在纤维特性上有显著差异，前者具有更长、更细、更强的纤维，备受推崇。更好地理解这些差异的遗传和潜在生物学原因将有助于通过育种和生物技术进一步提高棉花质量。我们评估了一个种间 Gh x Gb 重组自交系（RIL）群体在田间和温室条件下的 11 个独立实验中的纤维特性。地点位于 4 个大陆和 5 个国家，一些地点在多年内进行了分析。
RIL 群体在所有主要纤维性状上表现出很大的变异性。通过复合区间作图对每个位点进行了 QTL 分析。在 651 个假定的 QTL（LOD > 2）中，有 167 个 QTL 的 LOD 超过了基于置换的阈值。对强度、伸长率、长度、长度均匀性、细度/成熟度和颜色等纤维性状类别在数据集之间的 QTL 位置进行了一致性评估。使用 MetaQTL 软件对 1000 多个假定的 QTL 进行了荟萃分析，以整合来自 RIL 和 3 个回交群体（来自相同的亲本）的 QTL 数据，并将其与文献进行比较。尽管实验和群体之间的整体一致性水平通常是中等的，但对于 30 个性状 x 染色体组合（19 条不同染色体中的 5 个性状），可以进行 QTL 聚类，其中至少有 5 个不同数据集的单向（相似的加性效应）QTL 的有效共定位。在染色体 c6、c8 和 c25 上纤维颜色、c15 上细度和 c3 上纤维长度的一致元聚类被确定。
荟萃分析为跨多个群体和环境对复杂纤维性状的表型和遗传图谱数据进行整合提供了一种可靠的方法。对纤维质量性状有贡献的一致染色体区域是进一步解析重要纤维特性遗传和基因组因素以及进行标记辅助选择的良好候选区域。
