Nabateregga M, Mukankusi C, Raatz B, Edema R, Nkalubo S, Alladassi B M E
College of Agricultural and Environmental Science, Department of Agricultural Production, Makerere University, P. O. Box 7062 Kampala, Uganda.
International Centre for Tropical Agriculture (CIAT), P. O. Box 6247 Kampala, Uganda.
Afr J Biotechnol. 2019;18(21). doi: 10.5897/AJB2019.16768. Epub 2019 May 22.
Drought is a major constraint of common bean ( L.) production in Uganda where irrigation for the crop is very uncommon. This study aimed to identify quantitative trait loci (QTLs) underlying drought tolerance in 128 F5 RILs derived from an Andean intra-gene cross between drought-tolerant SEQ 1027 and BRB 191. Eighteen traits were evaluated under drought stress and non-stress conditions in the field for 2 years and in the greenhouse for 1 year, respectively. A linkage map spanning 486.29 cM was constructed using 53 single nucleotide polymorphic markers (SNP) markers obtained from the KASP genotyping assay. Eleven consistent QTLs were detected on five linkage groups at a threshold of Logarithm of Odds (LOD) ≥ 3.0. Four QTLs were constitutive, seven were adaptive and were associated with 100 seed weight, grain yield, chlorophyll content, harvest index, dry weight of leaf and stem biomass and yield production efficiency. The QTL associated with a 100 seed weight ( ) was the most consistent with the highest percentage of variation explained (21%). Co-localization of five drought-related factors QTLs was detected on pv10 suggesting pleiotropic effects on this chromosome. Identification of molecular markers closely linked to the QTLs identified in this study will facilitate marker assisted breeding for drought tolerance.
干旱是乌干达普通菜豆（Phaseolus vulgaris L.）生产的主要限制因素，该国该作物的灌溉并不常见。本研究旨在鉴定源自耐旱品种SEQ 1027和BRB 191之间安第斯基因内杂交的128个F5重组自交系（RIL）中耐旱性的数量性状位点（QTL）。分别在田间对18个性状进行了2年的干旱胁迫和非胁迫条件评估，在温室中进行了1年的评估。使用从竞争性等位基因特异性PCR（KASP）基因分型分析中获得的53个单核苷酸多态性（SNP）标记构建了一个跨度为486.29厘摩（cM）的连锁图谱。在对数优势（LOD）阈值≥3.0时，在五个连锁群上检测到11个一致的QTL。四个QTL是组成型的，七个是适应性的，与百粒重、籽粒产量、叶绿素含量、收获指数、叶和茎生物量干重以及产量生产效率相关。与百粒重相关的QTL解释的变异百分比最高（21%），是最一致的。在pv10上检测到五个与干旱相关因子QTL的共定位，表明该染色体上存在多效性效应。鉴定与本研究中鉴定的QTL紧密连锁的分子标记将有助于耐旱性的标记辅助育种。
