Biotechnology Unit and Bean Program, International Center for Tropical Agriculture (CIAT), Cali, Valle, Colombia.
Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia.
PLoS One. 2018 Aug 29;13(8):e0202342. doi: 10.1371/journal.pone.0202342. eCollection 2018.
Common bean productivity is reduced by several abiotic stress factors like drought and low soil fertility, leading to yield losses particularly in low input smallholder farming systems in the tropics. To understand the genetics of stress tolerance, and to improve adaptation of common bean to adverse environments, the BAT 881 x G21212 population of 95 recombinant inbred lines (RILs) was evaluated under different abiotic stress conditions in 15 trials across four locations in Colombia, representing two higher altitude (Darién, Popayán) and two lower altitude (Palmira, Quilichao) locations. Stress vs non-stress treatments showed that yields were reduced in drought trials in Palmira by 13 and 31%, respectively, and observed yield reductions in low phosphorus stress were 39% in Quilichao, 16% in Popayán, and 71% in Darién, respectively. Yield components and biomass traits were also reduced. Traits linked to dry matter redistribution from stems, leaves and pods to seed, such as pod harvest index and total non-structural carbohydrates, were found to be important factors contributing to yield in all conditions. In contrast, early maturity was correlated with improved yield only in lower altitude locations, whereas in higher altitudes delayed maturity promoted yield. Superior RILs that combine stress tolerance and high cross-location productivity were identified. Lines that showed good yield under strong stress conditions also performed well under non-stress conditions, indicating that breeder's selection can be applied for both conditions at the same time. Quantitative trait loci (QTL) analyses revealed a stable yield QTL on chromosome Pv04, detected individually in all locations, several stress treatments and in best linear unbiased predictions (BLUPs) across all trials. Furthermore, two QTL hotspots for maturity traits were identified on Pv01 and Pv08, which are the most stable QTL. The constitutive yield QTL could serve as a good candidate for marker development and could be used in marker assisted selection. Increased understanding of the physiology of abiotic stress tolerance, combined with the availability of superior germplasm and molecular tools, will aid breeding efforts for further improvement of these plant traits.
多种非生物胁迫因素（如干旱和土壤肥力低）会降低普通菜豆的生产力，导致产量损失，特别是在热带低投入小农户种植系统中。为了了解胁迫耐受性的遗传学，并改善普通菜豆对不利环境的适应能力，在哥伦比亚四个地点的 15 次试验中，对 95 个重组自交系（RIL）的 BAT 881 x G21212 群体进行了不同非生物胁迫条件的评估。在干旱试验中，帕米拉的产量分别降低了 13%和 31%，而在低磷胁迫下，观察到的产量降低分别为 39%在基里查奥，16%在波帕扬，71%在达连。产量构成和生物量特征也有所降低。与从茎、叶和荚向种子重新分配干物质有关的特征，如荚收获指数和总非结构性碳水化合物，被发现是所有条件下产量的重要因素。相比之下，早熟性仅与低海拔地区的产量提高相关，而在高海拔地区，延迟成熟可提高产量。鉴定出了既能耐受胁迫又能在多个地点提高生产力的优秀 RIL 系。在强胁迫条件下表现出良好产量的系在非胁迫条件下也表现良好，这表明选择育种可以同时应用于两种条件。数量性状位点（QTL）分析显示，在所有地点、多个胁迫处理和所有试验的最佳线性无偏预测（BLUP）中，Pv04 染色体上存在一个稳定的产量 QTL。此外，在 Pv01 和 Pv08 上鉴定出了两个成熟性状的 QTL 热点，这是最稳定的 QTL。组成性产量 QTL 可以作为标记开发的良好候选者，并可用于标记辅助选择。进一步了解非生物胁迫耐受性的生理学，结合优良种质资源和分子工具的可用性，将有助于这些植物性状的进一步改良。
