Wild and landrace progenitors of wheat are an important source of resistance to various types of environmental stress, which can be explored in wheat breeding. With the aim of providing genetic materials for breeding to generate drought-resistant varieties, 50 durum wheat landraces, breeding lines and local cultivars were evaluated at the seedling stage for biomass, physiological parameters (e.g. photosynthetic pigment and relative water contents) and activities of key enzymatic antioxidants [e.g. ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD)] under optimal and polyethylene glycol (PEG)-triggered water stress. We observed significant differences in the measured parameters among the durum wheat genotypes in response to PEG-induced water stress. Biomass and physiological traits showed a decreasing trend, whereas the antioxidant enzyme activities displayed an increasing trend in the investigated durum wheats under PEG-induced water stress. PEG-induced water stress decreased the average means of total soluble protein, chlorophyll a and total chlorophyll contents of the 50 investigated genotypes by 51.42, 36.77 and 26.15%, respectively, while the mean values of POD and SOD activities increased by 173.33 and 92.26%, respectively, relative to the control. A principal component analysis (PCA)-based biplot demonstrated that the stress tolerance index (STI) positively correlated with the root and shoot dry weights as well as CAT, SOD and APX activities. In conclusion, several breeding lines (e.g. G10, G19 and G20), Iranian landraces (e.g. G42 and G47) and local cultivar (G49) showed a better adaptive response to PEG-induced water stress than other tested genotypes, suggesting that these genotypes could be explored in various breeding programs to create new wheat cultivars with beneficial water stress-adaptive traits.

中文翻译：

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聚乙二醇诱导水分胁迫期间硬粒小麦苗期基因型生化和生理参数的评估

小麦的野生和地方品种祖先是抵抗各种环境胁迫的重要来源，可以在小麦育种中进行探索。为了为培育抗旱品种提供遗传材料，在苗期对 50 个硬粒小麦地方品种、育种系和地方栽培品种进行了生物量、生理参数（如光合色素和相对含水量）和活性的评估。酶促抗氧化剂 [例如抗坏血酸过氧化物酶 (APX)、过氧化氢酶 (CAT)、过氧化物酶 (POD) 和超氧化物歧化酶 (SOD)] 在最佳和聚乙二醇 (PEG) 触发的水分胁迫下。我们观察到硬粒小麦基因型响应 PEG 诱导的水分胁迫时测量参数的显着差异。生物量和生理性状呈下降趋势，而在PEG诱导的水分胁迫下，所研究的硬粒小麦的抗氧化酶活性显示出增加的趋势。PEG诱导的水分胁迫使50个研究基因型的总可溶性蛋白、叶绿素a和总叶绿素含量的平均平均值分别降低了51.42、36.77和26.15%，而POD和SOD活性的平均值分别增加了173.33和92.26% ，分别相对于对照。基于主成分分析 (PCA) 的双标图表明，胁迫耐受指数 (STI) 与根干重和地上部干重以及 CAT、SOD 和 APX 活性呈正相关。总之，几个育种系（例如 G10、G19 和 G20）、伊朗地方品种（例如