Zhang Wenshan, Hu Dandan, Raman Rosy, Guo Shaomin, Wei Zili, Shen Xueqi, Meng Jinling, Raman Harsh, Zou Jun
National Key Laboratory of Crop Genetic Improvement, Key Laboratory of Rapeseed Genetic Improvement, Ministry of Agriculture China, Huazhong Agricultural UniversityWuhan, China.
Graham Centre for Agricultural Innovation (an Alliance between the Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga Agricultural InstituteWagga Wagga, NSW, Australia.
Front Plant Sci. 2017 Apr 24;8:615. doi: 10.3389/fpls.2017.00615. eCollection 2017.
(BBCC) is an allotetraploid in with unique alleles for agronomic traits and has huge potential as source for biodiesel production. To investigate the genome-wide molecular diversity, population structure and linkage disequilibrium (LD) pattern in this species, we genotyped a panel of 81 accessions of with genotyping by sequencing approach DArTseq, generating a total of 54,510 polymorphic markers. Two subpopulations were exhibited in the accessions. The average distance of LD decay ( = 0.1) in B subgenome (0.25 Mb) was shorter than that of C subgenome (0.40 Mb). Genome-wide association analysis (GWAS) identified a total of seven markers significantly associated with five seed quality traits in two experiments. To further identify the quantitative trait loci (QTL) for important agronomic and seed quality traits, we phenotyped a doubled haploid (DH) mapping population derived from the "YW" cross between two parents (Y-BcDH64 and W-BcDH76) representing from the two subpopulations. The YW DH population and its parents were grown in three contrasting environments; spring (Hezheng and Xining, China), semi-winter (Wuhan, China), and spring (Wagga Wagga, Australia) across 5 years for QTL mapping. Genetic bases of phenotypic variation in seed yield and its seven related traits, and six seed quality traits were determined. A total of 282 consensus QTL accounting for these traits were identified including nine major QTL for flowering time, oleic acid, linolenic acid, pod number of main inflorescence, and seed weight. Of these, 109 and 134 QTL were specific to spring and semi-winter environment, respectively, while 39 consensus QTL were identified in both contrasting environments. Two QTL identified for linolenic acid (B3) and erucic acid (C7) were validated in the diverse lines used for GWAS. A total of 25 QTL accounting for flowering time, erucic acid, and oleic acid were aligned to the homologous QTL or candidate gene regions in the C genome of . These results would not only provide insights for genetic improvement of this species, but will also identify useful genetic variation hidden in the C subgenome of to improve canola cultivars.
（BBCC）是一种异源四倍体，具有独特的农艺性状等位基因，作为生物柴油生产的来源具有巨大潜力。为了研究该物种全基因组的分子多样性、群体结构和连锁不平衡（LD）模式，我们采用测序方法DArTseq对81份该物种材料进行基因分型，共产生了54510个多态性标记。这些材料中呈现出两个亚群。B亚基因组中LD衰减的平均距离（r² = 0.1）为0.25 Mb，短于C亚基因组的0.40 Mb。全基因组关联分析（GWAS）在两个实验中总共鉴定出7个与5个种子品质性状显著相关的标记。为了进一步鉴定重要农艺和种子品质性状的数量性状位点（QTL），我们对来自代表两个亚群的两个亲本（Y - BcDH64和W - BcDH76）之间“YW”杂交产生的双单倍体（DH）作图群体进行了表型分析。YW DH群体及其亲本在三种不同环境中种植；跨越5年，在中国的春季（和政、西宁）、半冬季（武汉）以及澳大利亚的春季（瓦加瓦加）进行QTL定位。确定了种子产量及其7个相关性状以及6个种子品质性状表型变异的遗传基础。共鉴定出282个解释这些性状的一致性QTL，包括9个控制开花时间、油酸、亚麻酸、主花序荚数和种子重量的主要QTL。其中，109个和134个QTL分别特定于春季和半冬季环境，而在两种不同环境中均鉴定出39个一致性QTL。在用于GWAS的不同品系中验证了两个鉴定出的与亚麻酸（B3）和芥酸（C7）相关的QTL。总共25个控制开花时间、芥酸和油酸的QTL与该物种C基因组中的同源QTL或候选基因区域对齐。这些结果不仅将为该物种的遗传改良提供见解，还将鉴定出隐藏在该物种C亚基因组中的有用遗传变异，以改良油菜品种。
