| Abstrakt: |
Introduction: Wheat is the most important food crop in the world in terms of cultivated area, commercial value and human nutrition. It plays the biggest role in providing food security in the world compared to other agricultural products. Drought is one of the major environmental factors which threaten wheat production worldwide. Drought and heat stress are two main factors reducing wheat productivity worldwide. Therefore, it is inevitable to improve and release new wheat cultivars adapted to adverse climate change. Drought stress during sensitive growth stages of wheat, including grain filling, decreases kernel weight and the number of grains in the spike, which results in a considerable drop in wheat yield. In recent years, numerous studies have focused on identifying wheat genotypes that are wellsuited to dry conditions. Local varieties and wild relatives are being explored as primary sources of drought tolerance. The results of these studies serve as a foundation for further research into specific species found within wheat germplasm. Materials and methods: Nineteen genotypes were studied in this research to identify the tolerant genotypes to drought stress. Nineteen indicators were used to assess the genotypes regarding sensitivity and resistance to drought stress. Due to the difference in the indicators' results, the RS rating was used for more accuracy, which is based on the average and standard deviation of the ratings. Finally, the top genotypes were recognized by this ranking. Results: Considering all indicators, Genotypes 11, 4, and 5 were ranked highest and recognized as drought-resistant genotypes. Principal component analysis was conducted for drought resistance indices, revealing that the first two components made the largest contribution in explaining the variance of the data. The first component accounted for 66.78% and the second component accounted for 32.50% of the total variance. Based on the calculated indices, genotypes were categorized into four distinct groups. Genotypes 11, 4, and 5, which were identified as the best genotypes based on RS, were grouped together. Through cluster analysis, genotypes were further classified into four groups: resistant, semi-resistant, semi-sensitive, and sensitive. Conclusion: The results showed that Genotypes 4, 5, 11, and 14 had the highest YS, HAM, and YI indices under drought stress conditions. In contrast, Genotypes 1, 6, 7, and 10 had the lowest YS and YI values. These findings align with previous research showing that grain yield in stress and non-stress conditions is the best criterion for evaluating drought resistance. [ABSTRACT FROM AUTHOR] |
