State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, Henan, China.
Agricultural College, Yangtze University, Jingzhou, 434000, China.
BMC Plant Biol. 2019 Apr 11;19(1):138. doi: 10.1186/s12870-019-1725-y.
Gossypium hirsutum L. is grown worldwide and is the largest source of natural fiber crop. We focus on exploring the favorable alleles (FAs) for upland cotton varieties improvement, and further understanding the history of accessions selection and acumination of favorable allele during breeding.
The genetic basis of phenotypic variation has been studied. But the accumulation of favorable alleles in cotton breeding history in unknown, and potential favorable alleles to enhance key agronomic traits in the future cotton varieties have not yet been identified. Therefore, 419 upland cotton accessions were screened, representing a diversity of phenotypic variations of 7362 G. hirsutum, and 15 major traits were investigated in 6 environments. These accessions were categorized into 3 periods (early, medium, and modern) according to breeding history. All accessions were divided into two major groups using 299 polymorphic microsatellite markers: G1 (high fiber yield and quality, late maturity) and G2 (low fiber yield and quality, early maturity). The proportion of G1 genotype gradually increased from early to modern breeding periods. Furthermore, 21 markers (71 alleles) were significantly associated (-log P > 4) with 15 agronomic traits in multiple environments. Seventeen alleles were identified as FAs; these alleles accumulated more in the modern period than in other periods, consistent with their phenotypic variation trends in breeding history. Our results demonstrate that the favorable alleles accumulated through breeding effects, especially for common favorable alleles. However, the potential elite accessions could be rapidly screened by rare favorable alleles.
In our study, genetic variation and genome-wide associations for 419 upland cotton accessions were analyzed. Two favorable allele types were identified during three breeding periods, providing important information for yield/quality improvement of upland cotton germplasm.
陆地棉（Gossypium hirsutum L.）在全球范围内广泛种植，是最大的天然纤维作物来源。我们专注于探索陆地棉品种改良的有利等位基因（FAs），并进一步了解在品种选育过程中，品种资源选择和有利等位基因积累的历史。
研究了表型变异的遗传基础。但棉花品种选育历史中有利等位基因的积累情况尚不清楚，也尚未确定未来棉花品种中潜在的有利等位基因来提高关键农艺性状。因此，筛选了 419 份陆地棉品种，代表了 7362 个陆地棉的表型变异多样性，并在 6 个环境中调查了 15 个主要性状。这些品种根据其选育历史分为 3 个时期（早期、中期和现代）。使用 299 个多态性微卫星标记将所有品种分为两个主要群体：G1（纤维产量和品质高，成熟晚）和 G2（纤维产量和品质低，成熟早）。G1 基因型的比例从早期到现代选育时期逐渐增加。此外，在多个环境中，21 个标记（71 个等位基因）与 15 个农艺性状显著相关（-log P>4）。鉴定出 17 个等位基因为有利等位基因；这些等位基因在现代时期的积累量多于其他时期，与它们在品种选育历史中的表型变异趋势一致。我们的结果表明，有利等位基因是通过选育效应积累的，特别是常见的有利等位基因。然而，通过稀有有利等位基因可以快速筛选出潜在的优良品种。
本研究分析了 419 份陆地棉品种的遗传变异和全基因组关联。在三个选育时期中鉴定出两种有利等位基因类型，为陆地棉种质的产量/品质改良提供了重要信息。
