Rice, a staple food crop for over half of the global population, is facing a serious threat of rising temperature due to climate change, especially in the areas producing Basmati rice. The main objectives of the study were to compare the promising cultivars of Basmati rice for heat stress tolerance and to assess how elevated temperature affects leaf physiological and morphological parameters of fine rice at seedling stage. A 2‐year‐controlled pot experiment was carried out to evaluate how different Basmati rice varieties respond to heat stress. The experiment was carried out at the Agronomic research area, University of Agriculture Faisalabad, Pakistan, during 2022 and 2023. The design of experiment was completely randomised design (CRD) with split treatment structure and four replications. Plant morphology, leaf temperature, chlorophyll contents, relative cell injury and relative water contents were evaluated for both experimental years. Heat stress significantly affected all morphological and physiological attributes such as chlorophyll contents, relative water contents and relative cell injury across different varieties. There was variation in the behaviour of different varieties under stress conditions as compared to no heat, but from the results it was very clear that Kisan Basmati and PK‐1121 Aromatic constantly showed poor performance under both conditions for all the recorded parameters. However, in almost each parameter evaluated, Basmati‐515, Super Basmati and NIAB‐16 exhibited Superior thermo tolerance and better performance. On the basis of observed morphological and physiological attributes, Kisan and PK‐1121 Aromatic Basmati were graded as sensitive varieties, while Basmati‐515, Super Basmati and NIAB‐16 showed tolerance to heat stress as compared to other varieties. However, further research is needed to explore the underlying mechanisms and genetic factors contributing to the sensitivity or tolerance observed in these varieties.

中文翻译：

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印度香米 （Oryza sativa L.） 的评价高温胁迫下幼苗生长和叶片生理学的基因型


水稻是全球一半以上人口的主食作物，由于气候变化，它正面临气温上升的严重威胁，尤其是在印度香米生产地区。该研究的主要目的是比较印度香米有前途的耐热性品种，并评估高温如何影响苗期细稻叶片的生理和形态参数。进行了一项为期 2 年的对照盆栽实验，以评估不同的印度香米品种对热应激的反应。该实验于 2022 年至 2023 年在巴基斯坦费萨拉巴德农业大学农艺研究区进行。实验设计为完全随机设计 （CRD），具有拆分处理结构和 4 个重复。对两个实验年份的植物形态、叶温、叶绿素含量、相对细胞损伤和相对水分含量进行了评价。热胁迫显著影响不同品种的叶绿素含量、相对水分含量和相对细胞损伤等所有形态和生理属性。与不加热相比，不同品种在胁迫条件下的行为存在变化，但从结果中可以非常清楚地看出，Kisan Basmati 和 PK-1121 芳香族在这两种条件下的所有记录参数都表现出较差的性能。然而，在评估的几乎所有参数中，印度香叶-515、超级印度香叶和 NIAB-16 都表现出卓越的耐热性和更好的性能。 根据观察到的形态和生理特性，Kisan 和 PK-1121 芳香印度香米被分级为敏感品种，而印度香米 515、超级印度香米和 NIAB-16 与其他品种相比表现出对热应激的耐受性。然而，需要进一步的研究来探索导致在这些品种中观察到的敏感性或耐受性的潜在机制和遗传因素。