عنوان مقاله [English]
Background and objectives: Among the important fungal diseases of wheat worldwide, there are three black, yellow and brown rusts that reduce its performance. Leaf rust caused by Puccinia triticina Eriks is one of the most destructive wheat diseases in some areas of the world including Iran ,which in addition to reducing grain yield, also causes a quality deterioration.. The purpose of this study was to evaluate a number of bread wheat cultivars based on traits and indices of leaf rust resistance due to the wheat yield at adult stage.
Materials and Methods: In this study, 41 bread wheat cultivars with susceptible Bolany cultivar was assessed under disease stress and non-stress conditions in the field of agricultural research center of Gorgan, Golestan. The experiment was evaluated under both without fungicide protection (stress) and with fungicide protection (non- stress) environments using a randomized complete block design with three replications, under mist irrigation. Resistance indices including infection type and area under disease progress curve (AUDPC) and morphological traits including spike length, No. spikelet per spike, No. grain per spikelet and 1000-grain weight, were evaluated under disease stress conditions and both conditions respectively.
Results: The analysis of variance showed that there was a significant difference among investigated cultivars this proved to be genetic variation and can be selection for leaf rust resistance. The results of composite analysis indicated that the leaf rust disease significantly affected spike length, number of grain per spikelet and grain thousand weight. There was a positive and significant correlation (0.98) between infection type and AUDPC. The grain number per spikelet percentage losses and the grain thousand weight percentage losses had positive correlation with resistance indices (infection type and AUDPC). Cluster analysis categorized the genotypes into four distinct groups. The resistance group consisted of ATRI 3856, Atrak. The semi-resistance group consisted of Frontana, ATRI9717, Gimaza, Arom, IRA9, ATRI 3315,Navid,Zare, 01C0204936, Morvarid, Ehsan, and Gonbad. The semi-sensitive group consisted of TRI 15593, ATRI 15657, Yavaros, ATRI 537, ATRI 525, SARC 6W, ATRI 527, ATRI 23666 and Tajan. The sensitive group consisted of other genotypes. Based on resources, semi- resistance and semi- sensitive groups can be introduced in order to increase resistance to disease. 3-D plots among AUDPC, decrease percentage of No. grain per spikelet and 1000-grain weight distinguished genotypes of ATRI 9717, Arom, IRA9, Zare, Morvarid, and Ehsan as the most resistant genotypes and the least yield decrease percentage in the semi- resistance and semi- sensitive groups.
Conclusion: According to the obtained results it can be stated that the genotypes of ATRI 3856 and Atrak, with partial disease it is possible to have specific resistance genes. Therefore, due to the probability that the resistance will break in shorter time, it is needed to be careful about using such genotypes. the genotypes of Arom, IRA9, Zare, ATRI 9717, Morvarid and Ehsan in semi-resistance group have medium resistance. Therefore, they can be introduced to perform breeding programs or supply to farmers.