Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Centre for Genetic Manipulation of Crop Plants, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
Theor Appl Genet. 2017 Feb;130(2):293-307. doi: 10.1007/s00122-016-2811-2. Epub 2016 Oct 15.
Seed weight QTL identified in different populations were synthesized into consensus QTL which were shown to harbor candidate genes by in silico mapping. Allelic variation inferred would be useful in breeding B. juncea lines with high seed weight. Seed weight is an important yield influencing trait in oilseed Brassicas and is a multigenic trait. Among the oilseed Brassicas, Brassica juncea harbors the maximum phenotypic variation wherein thousand seed weight varies from around 2.0 g to more than 7.0 g. In this study, we have undertaken quantitative trait locus/quantitative trait loci (QTL) analysis of seed weight in B. juncea using four bi-parental doubled-haploid populations. These four populations were derived from six lines (three Indian and three east European lines) with parental phenotypic values for thousand seed weight ranging from 2.0 to 7.6 g in different environments. Multi-environment QTL analysis of the four populations identified a total of 65 QTL ranging from 10 to 25 in each population. Meta-analysis of these component QTL of the four populations identified six 'consensus' QTL (C-QTL) in A3, A7, A10 and B3 by merging 33 of the 65 component Tsw QTL from different bi-parental populations. Allelic diversity analysis of these six C-QTL showed that Indian lines, Pusajaikisan and Varuna, hold the most positive allele in all the six C-QTL. In silico mapping of candidate genes with the consensus QTL localized 11 genes known to influence seed weight in Arabidopsis thaliana and also showed conserved crucifer blocks harboring seed weight QTL between the A subgenomes of B. juncea and B. rapa. These findings pave the way for a better understanding of the genetics of seed weight in the oilseed crop B. juncea and reveal the scope available for improvement of seed weight through marker-assisted breeding.
在不同群体中鉴定的种子重量 QTL 被综合为共识 QTL，通过计算机映射显示这些 QTL 含有候选基因。推断的等位基因变异将有助于培育具有高种子重量的芥菜型油菜品系。种子重量是油料作物芸薹属中一个重要的产量影响性状，是一个多基因性状。在油料作物芸薹属中，芥菜型油菜含有最大的表型变异，千粒重从 2.0 克到 7.0 克以上不等。在这项研究中，我们使用四个双单倍体群体对芥菜型油菜的种子重量进行了数量性状位点/数量性状位点（QTL）分析。这四个群体来自六个系（三个印度系和三个东欧系），其亲本千粒重表型值在不同环境下从 2.0 到 7.6 克不等。对这四个群体的多环境 QTL 分析共鉴定出 65 个 QTL，每个群体从 10 到 25 个。对这四个群体的组成 QTL 的元分析，通过合并来自不同双单倍体群体的 65 个组成 Tsw QTL 中的 33 个，在 A3、A7、A10 和 B3 中鉴定出六个“共识”QTL（C-QTL）。对这六个 C-QTL 的等位基因多样性分析表明，印度系 Pusajaikisan 和 Varuna 在所有六个 C-QTL 中都含有最积极的等位基因。与共识 QTL 定位的候选基因的计算机映射定位了 11 个已知影响拟南芥种子重量的基因，也显示了芥菜型油菜和油菜 A 亚基因组之间含有种子重量 QTL 的保守十字花科块。这些发现为更好地理解油料作物芥菜型油菜的种子重量遗传学铺平了道路，并揭示了通过标记辅助选择提高种子重量的范围。
