School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa.
PLoS One. 2024 Aug 6;19(8):e0306263. doi: 10.1371/journal.pone.0306263. eCollection 2024.
Striga hermonthica (Sh) and S. asiatica (Sa) are major parasitic weeds limiting cereal crop production and productivity in sub-Saharan Africa (SSA). Under severe infestation, Striga causes yield losses of up to 100%. Breeding for Striga-resistant maize varieties is the most effective and economical approach to controlling the parasite. Well-characterized and genetically differentiated maize germplasm is vital to developing inbred lines, hybrids, and synthetic varieties with Striga resistance and desirable product profiles. The objective of this study was to determine the genetic diversity of 130 tropical and sub-tropical maize inbred lines, hybrids, and open-pollinated varieties germplasm using phenotypic traits and single nucleotide polymorphism (SNP) markers to select Striga-resistant and complementary genotypes for breeding. The test genotypes were phenotyped with Sh and Sa infestations using a 13x10 alpha lattice design with two replications. Agro-morphological traits and Striga-resistance damage parameters were recorded under a controlled environment. Further, high-density Diversity Array Technology Sequencing-derived SNP markers were used to profile the test genotypes. Significant phenotypic differences (P<0.001) were detected among the assessed genotypes for the assessed traits. The SNP markers revealed mean gene diversity and polymorphic information content of 0.34 and 0.44, respectively, supporting the phenotypic variation of the test genotypes. Higher significant variation was recorded within populations (85%) than between populations using the analysis of molecular variance. The Structure analysis allocated the test genotypes into eight major clusters (K = 8) in concordance with the principal coordinate analysis (PCoA). The following genetically distant inbred lines were selected, displaying good agronomic performance and Sa and Sh resistance: CML540, TZISTR25, TZISTR1248, CLHP0303, TZISTR1174, TZSTRI113, TZDEEI50, TZSTRI115, CML539, TZISTR1015, CZL99017, CML451, CML566, CLHP0343 and CML440. Genetically diverse and complementary lines were selected among the tropical and sub-tropical maize populations that will facilitate the breeding of maize varieties with Striga resistance and market-preferred traits.
密花高粱(Sh)和亚洲高粱(Sa)是限制撒哈拉以南非洲(SSA)谷类作物生产和生产力的主要寄生杂草。在严重感染的情况下,Striga 会导致高达 100%的产量损失。培育抗 Striga 的玉米品种是控制寄生虫最有效和经济的方法。具有良好特征和遗传分化的玉米种质对于开发具有 Striga 抗性和理想产品特征的自交系、杂交种和合成品种至关重要。本研究的目的是利用表型性状和单核苷酸多态性(SNP)标记来确定 130 个热带和亚热带玉米自交系、杂交种和开放授粉品种的遗传多样性,以选择抗 Striga 和互补基因型进行育种。使用 13x10 alpha 格子设计和两个重复,用 Sh 和 Sa 侵染对测试基因型进行表型分析。在受控环境下记录农艺形态特征和 Striga 抗性损伤参数。此外,还使用高密度多样性阵列技术测序衍生的 SNP 标记对测试基因型进行分析。在所评估的性状中,评估的基因型之间存在显著的表型差异(P<0.001)。SNP 标记显示平均基因多样性和多态信息含量分别为 0.34 和 0.44,支持测试基因型的表型变异。使用分子方差分析记录到种群内的显著更高的变异(85%)高于种群间的变异。结构分析将测试基因型分为八个主要聚类(K = 8),与主坐标分析(PCoA)一致。选择了以下遗传上较远的自交系,表现出良好的农艺性能和 Sa 和 Sh 抗性:CML540、TZISTR25、TZISTR1248、CLHP0303、TZISTR1174、TZSTRI113、TZDEEI50、TZSTRI115、CML539、TZISTR1015、CZL99017、CML451、CML566、CLHP0343 和 CML440。在热带和亚热带玉米群体中选择了遗传上多样化和互补的系,这将有助于培育具有 Striga 抗性和市场偏好特征的玉米品种。