نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانش‌آموخته دکتری، گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه مراغه، ایران
2 استاد، گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاوزی، دانشگاه مراغه، مراغه، ایران
3 دانشیار، گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاوزی، دانشگاه مراغه، مراغه، ایران
4 استاد پژوهش، موسسه تحقیقات کشاورزی دیم کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، مراغه، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Today, wheat production as the most important crop in the world has been affected by increasing climate changes. In this regard, it is very important to investigate the physiological and agronomical responses of tolerant and sensitive wheat genotypes to drought stress under variabl rainfed conditions, along with identifying the relationships between the characteristics of resistance and sensitivity to this stress. For this purpose, the present study was conducted to investigate the effect of rainfed and supplementary irrigation conditions on physiological, biochemical and grain yield-related traits in bread wheat.
Materials and methods
The plant materials of this study were four bread wheat genotypes, including two resistant (with suitable and high grain yield under rainfed conditions and two sensitive genotypes with poor grain yield under rainfed conditions. The genotypes were evaluated under rainfed (drought stress) and supplementary irrigation conditions in a split plots design based on randomized complete block design with three replications in the Dryland Agricultural Research Institute, Maragheh, Iran, in 2021-2022 cropping year. Supplementary irrigation was applied after planting and at the booting stage. To identift differences among genotypes, antioxidant enzymes activites, oxidative damage, biochemical characteristics, and grain yield and yield components were measured. All statistical analyses were performed using SAS software and comparison of means were done using LSD test at the probability level of 5%.
Research findings
The results of this study showed that the degree of sensitivity and tolerance of the studied genotypes in response to drought stress was significantly different. In general, the activity level of antioxidant enzymes in rainfed conditions was higher than the supplementary irrigation. The highest enzymatic activity and the lowest levels of hydrogen peroxide and malondialdehyde were observed in genotype number 4 under rainfed conditions, while the lowest enzymatic activity and the highest levels of hydrogen peroxide and malondialdehyde were recorded in genotype number 40 under supplementary irrigation conditions. Morever, the highest proline content was observed in genotype number 4 under rainfed conditions and the lowest proline content was observed in genotypes 30 and 40 under supplementary irrigation conditions. The yield and yield components of the studied genotypes also revealed a similar trend as a result of the internal changes of the plant, such that the highest number of spikes per unit area and number of grains per spike were observed in genotypes 4 and 33 under supplementary irrigation, while genotypes 30 and 40 had the lowest values of these traits under rainfed conditions. The 1000-kernel weight of these genotypes had a similar trend, although with a lower slope. Investigating the changes in chlorophyll content and enzymatic activities in these genotypes can justify this trend.
Conclusion
The findings of this study showed that although all studied genotypes were affected by the treatments, drought-tolerant genotypes showed better performance under stress conditions compared to sensitive genotypes by increasing proline concentration, maintaining chlorophyll capacity, and intensifying antioxidant enzyme activity, and consequently had less yield reduction under stress conditions. Preventing the increase of hydrogen peroxide and malondialdehyde in these genotypes can confirm and complement this result and help to achieve higher yield in variable rainfed conditions. In addition, among the yield components, the number of grains per spike followed by spikes per unit area had the highest direct effect on grain yield. This could justify the need to focus more on these components in field examinations in order to obtain appropriate yield easier and faster.
کلیدواژه‌ها [English]
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