National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China.
PLoS One. 2012;7(9):e45215. doi: 10.1371/journal.pone.0045215. Epub 2012 Sep 24.
High yield is the most important goal in crop breeding, and boron (B) is an essential micronutrient for plants. However, B deficiency, leading to yield decreases, is an agricultural problem worldwide. Brassica napus is one of the most sensitive crops to B deficiency, and considerable genotypic variation exists among different cultivars in response to B deficiency. To dissect the genetic basis of tolerance to B deficiency in B. napus, we carried out QTL analysis for seed yield and yield-related traits under low and normal B conditions using the double haploid population (TNDH) by two-year and the BQDH population by three-year field trials. In total, 80 putative QTLs and 42 epistatic interactions for seed yield, plant height, branch number, pod number, seed number, seed weight and B efficiency coefficient (BEC) were identified under low and normal B conditions, singly explaining 4.15-23.16% and 0.53-14.38% of the phenotypic variation. An additive effect of putative QTLs was a more important controlling factor than the additive-additive effect of epistatic interactions. Four QTL-by-environment interactions and 7 interactions between epistatic interactions and the environment contributed to 1.27-4.95% and 1.17-3.68% of the phenotypic variation, respectively. The chromosome region on A2 of SYLB-A2 for seed yield under low B condition and BEC-A2 for BEC in the two populations was equivalent to the region of a reported major QTL, BE1. The B. napus homologous genes of Bra020592 and Bra020595 mapped to the A2 region and were speculated to be candidate genes for B efficiency. These findings reveal the complex genetic basis of B efficiency in B. napus. They provide a basis for the fine mapping and cloning of the B efficiency genes and for breeding B-efficient cultivars by marker-assisted selection (MAS).
高产量是作物育种最重要的目标，硼（B）是植物必需的微量元素。然而，硼缺乏导致产量下降，这是一个全球性的农业问题。甘蓝型油菜是对硼缺乏最敏感的作物之一，不同品种对硼缺乏的反应存在显著的遗传变异。为了解析甘蓝型油菜对硼缺乏的耐受性的遗传基础，我们使用双单倍体群体（TNDH）进行了两年田间试验和 BQDH 群体进行了三年田间试验，对低硼和正常硼条件下的种子产量和产量相关性状进行了 QTL 分析。总共鉴定到了 80 个在低硼和正常硼条件下与种子产量、株高、分枝数、角果数、种子数、种子重量和硼效率系数（BEC）相关的 QTL 及其 42 个上位性互作，分别解释了 4.15-23.16%和 0.53-14.38%的表型变异。QTL 的加性效应是比上位性互作的加性-加性效应更重要的控制因素。四个 QTL-环境互作和 7 个上位性互作与环境之间的互作分别解释了 1.27-4.95%和 1.17-3.68%的表型变异。低硼条件下 A2 染色体区域的 SYLB-A2 对种子产量的 QTL 和两个群体中 BEC-A2 对 BEC 的 QTL 与报道的主要 QTL BE1 的区域相当。定位到 A2 区域的 Bra020592 和 Bra020595 的甘蓝型油菜同源基因被推测为硼效率的候选基因。这些发现揭示了甘蓝型油菜硼效率的复杂遗传基础。它们为硼效率基因的精细定位和克隆以及通过标记辅助选择（MAS）培育硼高效品种提供了基础。
