Introduction: Wheat (Triticum aesivum L.) is a main and important crop that is widely cultivated in a wide range of regions and is one of the main sources of carbohydrates, protein, fiber, amino acids, and vitamins. Among the factors that limit yield in the natural state is water being the most important factor that, especially in arid and semi-arid regions of the world, including Iran, causes restrictions on planting in various ways. In many semi-arid environments, the relative humidity is at its highest at the beginning of the growing season and decreases with increasing temperature and cessation of rainfall. In these areas, the period of grain filling usually coincides with the lack of water and the increase of evaporation, and as a result, the yield decreases. The decrease in yield for wheat, the most important grain needed by mankind, makes it difficult to meet the food needs of the growing population. Therefore, it reveals the importance of more studies on drought stress and wheat encouraging the breeders towards the development of resistant cultivars.
Materials and methods: This research was carried out in the crop year of 2019-1400 with the aim of evaluating the stress tolerance of 50 recombinant wheat lines in the research farm of Gonbad Kavous University. This experiment was carried out in the form of a randomized complete block design on 50 different wheat lines resulting from the crossing of Gonbad cultivars in Zagros with three replications and on two planting dates (November 23, Bahman 10). The first factor included 50 different wheat lines resulting from the crossing of Gonbad cultivars in Zagros and the second factor included two planting dates (November 23 and Bahman 10). Three rows of two meters were cultivated for each line, with a distance of 20 cm between the rows and 40 cm between the experimental units. Then, non-living plant stress indices were calculated using iPASTIC software. Then the obtained indices were analyzed using a completely random design.
Results: The results of analysis of variance indicated the significance of the difference between the investigated lines under drought and normal stress conditions. The results of the average comparison between the studied lines and the indicators of resistance to drought stress showed that line 7 had good resistance in drought stress conditions. Correlation between drought tolerance indices and grain yield under drought stress conditions was calculated. The results of correlation analysis between stress tolerance and grain yield indices showed a positive and significant correlation between SSI and TOL indices. In this research, since MP and STI showed a high, positive and significant correlation with performance in stress-free and stress-free conditions. Therefore, they were introduced as superior indicators. In this research, the correlation of stress resistance indices with performance was investigated. Based on the results obtained from the performance of wheat lines and the estimation of their sensitivity to stress, lines 34 and 26 had the highest resistance among the investigated lines. Lane 5 was classified as one of the most sensitive among all lanes in terms of stress resistance indicators.
Conclusion: In general, in this research, since the average productivity (MP) and Fernandez index (STI) indicators showed a high, positive, and significant correlation with performance in stress-free and stressful conditions, they were therefore introduced as superior indicators. Based on these results, it can be said that lines 12, 16, and 20 are lines with high resistance. |
