Chipeta Michael M, Kafwambira John, Yohane Esnart
Department of Crop and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi.
Department of Agricultural Research Services, Chitedze Research Station, Lilongwe, Malawi.
Front Plant Sci. 2025 Jan 20;15:1461631. doi: 10.3389/fpls.2024.1461631. eCollection 2024.
This study focuses on cowpea, a vital crop for smallholder farmers in sub-Saharan Africa, particularly in Malawi. The research aimed to understand the genetic diversity and population structure of cowpea and to perform genome-wide association studies (GWAS) to identify marker-trait associations (MTAs) for yield and related traits. These insights are intended to support varietal development and address agricultural challenges in Malawi.
A total of 306 cowpea genotypes were characterized using single nucleotide polymorphism (SNP) markers and morphological traits. The study assessed the effects of genotype, location, and their interactions on morphological traits. The Fixed and Random Model Circulating Probability Unification (FarmCPU) algorithm was used to identify significant MTAs.
The morphological traits showed significant genotype, location, and interaction effects. Genotypes MWcp24, MWcp47, MWcp2232, and TVu-3524 yielded the highest values. Grain yield was positively correlated with peduncle length, seeds per pod, and pods per plant. Three distinct clusters were identified based on morphological traits. Genetic diversity analysis revealed an average minor allele frequency of 0.31, observed heterozygosity of 0.06, and gene diversity of 0.33. The average inbreeding coefficient was 0.82, indicating a high level of inbreeding. Most of the genetic variation (73.1%) was found among genotypes within populations. Nine groups and ancestral populations were identified, which did not entirely overlap with geographic origins. Sixteen significant MTAs were linked to six morphological traits.
The validation of these identified MTAs, along with the observed genetic diversity, offers valuable opportunities for cowpea improvement through marker-assisted selection, to addresses the challenges faced by Malawian farmers. The identification of thirty cowpea lines as key founder lines for breeding programs in Malawi, Mozambique, and Tanzania is a significant outcome. These efforts aim to develop more productive cowpea lines for the region, enhancing food security and agricultural sustainability.
本研究聚焦豇豆，这是撒哈拉以南非洲地区（尤其是马拉维）小农户的重要作物。该研究旨在了解豇豆的遗传多样性和群体结构，并开展全基因组关联研究（GWAS），以确定产量及相关性状的标记-性状关联（MTA）。这些见解旨在支持品种改良，应对马拉维的农业挑战。
使用单核苷酸多态性（SNP）标记和形态性状对总共306个豇豆基因型进行了表征。该研究评估了基因型、地点及其相互作用对形态性状的影响。采用固定和随机模型循环概率统一法（FarmCPU）算法来识别显著的MTA。
形态性状显示出显著的基因型、地点和相互作用效应。基因型MWcp24、MWcp47、MWcp2232和TVu-3524的表现值最高。籽粒产量与花梗长度、每荚种子数和单株荚数呈正相关。基于形态性状确定了三个不同的聚类。遗传多样性分析显示，平均次要等位基因频率为0.31，观察到的杂合度为0.06，基因多样性为0.33。平均近交系数为0.82，表明近交程度较高。大部分遗传变异（73.1%）存在于群体内的基因型之间。确定了九个组和祖先群体，它们与地理起源并不完全重叠。16个显著的MTA与六个形态性状相关。
这些已识别的MTA的验证，以及观察到的遗传多样性，为通过标记辅助选择改良豇豆提供了宝贵机会，以应对马拉维农民面临的挑战。确定30个豇豆品系作为马拉维、莫桑比克和坦桑尼亚育种计划的关键奠基品系是一项重要成果。这些努力旨在为该地区培育出产量更高的豇豆品系，加强粮食安全和农业可持续性。
