Ahmed Kashif, Shabbir Ghulam, Ahmed Mukhtar
Directorate of Cereal Crops, Agriculture Research Institute, Islamabad, Pakistan.
Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan.
BMC Plant Biol. 2025 Mar 27;25(1):390. doi: 10.1186/s12870-025-06345-9.
Wheat holds crucial global importance as a staple food in many regions. Drought stress significantly impedes seed germination of wheat. The lack of drought-tolerant wheat varieties hampers wheat production, especially in arid regions of the world. This study investigated seed germination and seedling growth in eighty wheat genotypes under moisture stress stimulated by polyethylene glycol (PEG). The study included two osmotic potentials induced by PEG-20% (ψ: -0.491 MPa) and PEG-25% (ψ: -0.735 MPa), as well as a control set without PEG. The data showed that dehydration caused by polyethylene glycol generally had an adverse effect on the morphological characteristics of wheat seedlings by causing substantial losses during the early germination stage. The results acquired from analysis of variance explained highly significant variances (p < 0.01) across genotypes (G), PEG-Treatments (T), and interactions between genotypes and PEG-Treatments (G x T) for all observed variables. Moisture deficit radically affected all studied seedling traits of bread wheat under rising osmotic stress, with germination percentage (GP), shoot length (SL), root length (RL), coleoptile length (CL), seedling length (SDL), root fresh weight (FRW), root dry weight (DRW), shoot fresh weight (FSW), shoot dry weight (DSW), seedling biomass (SBM) and seedling vigor index (SVI) reduced by about 30-95% compared to control (PEG-0%) to the maximum induced osmotic stress at -0.735 MPa. The coefficient of relative inhibition (CRI) rose in response to osmotic stress, demonstrating growth inhibition. Boxplots demonstrated a considerable decline under stress, although scatter plots and correlation matrices revealed significant positive associations for most seedling traits, except CRI. The histograms for most variables showed a wider value range and more diversified distribution patterns. Principal component analysis (PCA) and genotype by trait biplot emphasized that PC1 represented 94.29% of the cumulative variation, with an eigenvalue of 11.31 out of 12 components. The heatmap displayed diverse genotype and trait characteristics, indicating higher values for drought resistance and lower values for susceptibility in genotype performance. As indicated by a range of multivariate analyses, the wheat lines NR-499, NARC-2009 and Pakistan-2013 stood out as the most drought-tolerant among the genotypes; whereas Borlaug-2016, NR-514 and NR-516 were found to be highly susceptible, whereas SBM, SDL, SVI and CRI have been found key indicators for subsequent screening. These tolerant wheat lines offer promising potential for developing drought-tolerant varieties that could thrive in arid regions, thereby strengthening wheat production in water-stressed environments. Integrating these findings into breeding programs is crucial for realizing the potential of drought-tolerant wheat varieties in transforming global wheat production.
小麦作为许多地区的主食，在全球具有至关重要的地位。干旱胁迫严重阻碍小麦种子萌发。缺乏耐旱小麦品种阻碍了小麦生产，特别是在世界干旱地区。本研究调查了80个小麦基因型在聚乙二醇（PEG）刺激的水分胁迫下的种子萌发和幼苗生长情况。该研究包括由PEG - 20%（ψ：-0.491 MPa）和PEG - 25%（ψ：-0.735 MPa）诱导的两个渗透势，以及一个无PEG的对照组。数据表明，聚乙二醇引起的脱水通常对小麦幼苗的形态特征产生不利影响，在早期萌发阶段造成大量损失。方差分析结果表明，对于所有观察变量，基因型（G）、PEG处理（T）以及基因型与PEG处理之间的相互作用（G×T）均存在极显著差异（p < 0.01）。在渗透胁迫增加的情况下，水分亏缺对所有研究的面包小麦幼苗性状产生了根本性影响，与对照（PEG - 0%）相比，发芽率（GP）、苗长（SL）、根长（RL）、胚芽鞘长（CL）、幼苗长度（SDL）、根鲜重（FRW）、根干重（DRW）、苗鲜重（FSW）、苗干重（DSW）、幼苗生物量（SBM）和幼苗活力指数（SVI）在最大诱导渗透胁迫为-0.735 MPa时降低了约30 - 95%。相对抑制系数（CRI）随着渗透胁迫而升高，表明生长受到抑制。箱线图显示胁迫下显著下降，尽管散点图和相关矩阵显示除CRI外，大多数幼苗性状之间存在显著正相关。大多数变量的直方图显示值范围更广且分布模式更多样化。主成分分析（PCA）和基因型与性状双标图强调PC1代表了94.29%的累积变异，在12个成分中特征值为11.31。热图显示了不同的基因型和性状特征，表明基因型表现中抗旱性值较高而敏感性值较低。一系列多变量分析表明，小麦品系NR - 499、NARC - 2009和巴基斯坦 - 2013在基因型中表现出最耐旱；而Borlaug - 2016、NR - 514和NR - 516被发现高度敏感，而SBM、SDL、SVI和CRI已被发现是后续筛选的关键指标。这些耐旱小麦品系为培育能够在干旱地区茁壮成长的耐旱品种提供了有前景的潜力，从而加强水分胁迫环境下的小麦生产。将这些发现整合到育种计划中对于实现耐旱小麦品种在全球小麦生产转型中的潜力至关重要。
