Saleh Haitham, Badr Abdelfattah, Zayed Ehab M, Soliman Elham R S
Botany and Microbiology Department, Faculty of Science, Helwan University, Ain Helwan, Cairo, 11795, Egypt.
Cell Study Research Department, Field Crops Research Institute, Agricultural Research Center, Giza, 12619, Egypt.
Biochem Genet. 2024 Dec 23. doi: 10.1007/s10528-024-10965-5.
Pearl millet {Pennisetum glaucum (L.) R. Br} is a C4 panicoid cereal millet crop grown in arid and semi-arid regions in Africa and Asia for food and fodder. This study involves the evaluation of the genetic diversity of 28 worldwide germplasm collection of pearl millet by genetic markers polymorphism and drought tolerance indices. The genetic diversity was expressed by 51 alleles of 9 ISSR markers that showed 96.43% total polymorphism and 11.76 alleles per marker. Cluster analysis of ISSR markers polymorphism divided the 28 genotypes into four clusters partially in agreement with their origin. The application of drought stress simulated by 20% PEG treatment, retarded the germination percentage, and reduced shoot and root length, seedling fresh and dry weights. Drought tolerance indices (DTIs) were calculated based on the response of the seedling traits under drought stress compared to the control seedlings. ANOVA revealed statistically significant variation among the genotypes (P ≤ 0.05), except for seedling fresh weight (P = 0.17 > 0.05) under control conditions and seedling dry weight (P = 0.99 > 0.05) under drought conditions. Genotypes having higher DTIs for three traits are regarded drought resistant, i.e., those from India, Ethiopia, Pakistan, and Nigeria. The calculated heritability values indicated that seedlings dry weight is the least trait affected by drought stress whereas root length is the most influenced trait. Hierarchical clustering, based on the DTI values, also grouped the genotypes partially concomitant to their origin. The correlation analysis demonstrated a modest positive correlation between shoot length and root length. A low correlation of r ≤ 0.12 was observed between the morphological DTI matrix and the genetic matrix. Nevertheless, high levels of genetic diversity were identified among the examined genotypes that may face genetic erosion by climatic constraints, and a high potential for creating agronomically superior cultivars by crossing widely divergent genotypes.
珍珠粟（Pennisetum glaucum (L.) R. Br）是一种C4类黍属谷类作物，生长于非洲和亚洲的干旱及半干旱地区，用于食用和饲料。本研究通过遗传标记多态性和耐旱性指标，对28份全球珍珠粟种质资源的遗传多样性进行评估。遗传多样性由9个ISSR标记的51个等位基因表示，总多态性为96.43%，每个标记平均有11.76个等位基因。基于ISSR标记多态性的聚类分析将28个基因型分为四个类群，部分与它们的起源一致。用20% PEG处理模拟干旱胁迫，降低了发芽率，减少了地上部和根的长度、幼苗鲜重和干重。根据干旱胁迫下幼苗性状与对照幼苗的响应计算耐旱性指标（DTIs）。方差分析显示，除对照条件下的幼苗鲜重（P = 0.17＞0.05）和干旱条件下的幼苗干重（P = 0.99＞0.05）外，各基因型间存在显著差异（P≤0.05）。三个性状DTIs较高的基因型被认为具有抗旱性，即来自印度、埃塞俄比亚、巴基斯坦和尼日利亚的基因型。计算得到的遗传力值表明，幼苗干重是受干旱胁迫影响最小的性状，而根长是受影响最大的性状。基于DTI值的层次聚类也将基因型部分地按其起源进行了分组。相关性分析表明地上部长度与根长之间存在适度正相关。形态学DTI矩阵与遗传矩阵之间的相关性较低，r≤0.12。然而，在所检测的基因型中发现了高水平的遗传多样性，这些基因型可能因气候限制而面临遗传侵蚀，并且通过杂交广泛不同的基因型具有创造农艺学上优良品种的巨大潜力。
