Productivity of cowpea [Vigna unguiculata (L.) Walp] in sub-Sahara Africa is curtailed by a lack of farmer-preferred and improved cultivars and modern production technologies. The objectives of the study were to determine the extent of genetic diversity present among a collection of cowpea accessions from Zambia and Malawi using phenotypic traits and single nucleotide polymorphism (SNP) markers and, to select distinct and complementary parental lines for cultivar development. One hundred cowpea genotypes were evaluated for agronomic traits in two selected sites in Zambia, using a 10 × 10 alpha lattice design with two replications. Ninety-four of the test genotypes were profiled with 14,116 SNP markers. Number of pods plant− 1 (NPP), pod length (PDL), and number of seeds pod− 1 (NSP), were significantly (p < 0.05) affected by genotype × environment interaction effects. Genotypes such as CP411, CP421, CP645, CP732, Chimponongo, and MS1–8–1-4 exhibited higher grain yield of > 1200 kg/ha with excellent performance in yield components such as NSP, PDL, HSW and GYD. Grain yield had significant (p < 0.05) associations with NPP (r = 0.50), NSP (r = 0.46) and PDL (r = 0.42) useful for simultaneous selection for yield improvement in cowpea. The SNP markers revealed gene diversity and polymorphic information content of 0.22 and 0.17, respectively, showing that the tested cowpea accessions were genetically diverse. Test genotypes were classified into four genetic groups irrespective of source of collection allowing selection and subsequent crosses to develop breeding populations for cultivar development. Genotypes Bubebe, CP411, CP421, CP645, Chimponogo and MS1–8–1-4 were identified to be the most genetically divergent and high yielding making them ideal parental lines for breeding. This study provided a baseline information and identified promising cowpea genetic resources for effective breeding and systematic conservation.

中文翻译：

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使用表型性状和SNP标记评估cow豆[Vigna unguiculata（L.）Walp。]种质的遗传多样性。

撒哈拉以南非洲的cow豆[Vigna unguiculata（L.）Walp]的生产力因缺乏农民偏爱的改良品种和现代生产技术而受到限制。该研究的目的是利用表型性状和单核苷酸多态性（SNP）标记确定来自赞比亚和马拉维的cow豆种质中的遗传多样性程度，并选择不同和互补的亲本系进行品种开发。使用10×10α格子设计和两次重复，评估了100个cow豆基因型在赞比亚两个选定地点的农艺性状。用14,116个SNP标记分析了94个测试基因型。荚果植物-1（NPP）的数量，荚果长度（PDL）和荚果-1（NSP）的种子数量显着（p <0。05）受基因型×环境相互作用的影响。基因型（例如CP411，CP421，CP645，CP732，Chimponongo和MS1–8–1-4）表现出更高的谷物产量，> 1200 kg / ha，在诸如NSP，PDL，HSW和GYD等产量成分上表现出色。谷物产量与NPP（r = 0.50），NSP（r = 0.46）和PDL（r = 0.42）有显着（p <0.05）关联，可用于同时选择以提高cow豆的产量。SNP标记揭示了基因多样性和多态信息含量分别为0.22和0.17，表明所测试的cow豆种质具有遗传多样性。测试基因型被分为四个基因组，而与收集来源无关，从而允许选择和随后的杂交来发展用于品种开发的育种种群。基因型Bubebe，CP411，CP421，CP645，Chimponogo和MS1–8–1-4被确定为遗传差异最大，产量最高的品种，使其成为理想的育种亲本系。这项研究提供了基本信息，并确定了有希望的cow豆遗传资源，可进行有效育种和系统保护。