واکنش لاین‌های گندم آزمایشات مقایسه عملکرد ناحیه‌ای امیدبخش اقلیم گرم و مرطوب شمال در سال 1400 (ERWYT-N-1400) نسبت به بیماری بلایت فوزاریومی سنبله در شرایط مزرعه و گلخانه

Fusarium head blight disease (FHB) of wheat, mainly caused Fusarium graminearum, is one of the most destructive diseases of wheat in Iran especially in warm and humid climate. The present study was conducted in order to investigate the reaction of 20 lines of Elite Regional Wheat Yield Trial from the North warm and humid climate in 2021 (ERWYT-1400) during two crop years of 2021-02 and 2022-03 under field conditions in Gorgan and Moghan and also in the greenhouse in Karaj. Both of the field and greenhouse studies were conducted in the frame of randomized complete block design (RCBD) with three replications. To carry out the experiment in the field, wheat lines were planted on one-meter-long rows, and were inoculated by spraying using a suspension of spores of Fusarium graminearum at flowering. Three weeks after inoculation, rate of disease incidence and severity were recorded and disease index was calculated through them. To carry out the experiment in the greenhouse, wheat lines were planted in plastic pots with a diameter and height of 15 cm and were inoculated by point inoculation method using a suspension of spores of Fusarium graminearum at flowering. Three weeks after, rate of disease spread (disease severity) was determined as the ratio of infected spikes to total spikes of a spike. Considering the relatively low disease level in the first year of the experiment in Moghan, data obtained from the three other environments (Gorgan-1st year, Gorgan-2nd year, and Moghan-2nd year) were used for analysis. Analysis of variance of the data of disease index obtained from the three environments showed a significant difference between the genotypes. Comparison of means of disease index by Duncan's method showed that the susceptible check cultivar Falat having the highest disease index (38.9%) were placed in group A, the experimental line N-1400-4 having the lowest disease index (5.1%) in group E, and other genotypes with disease indexes between these two limits, in the groups between them. In addition to the line N-1400-4, three other lines including N-1400-2 (commercial check cultivar Arman), N-1400-16, and N-1400-14, with disease indexes between 5.4 and 9.7%, were in the next positions in terms of disease resistance, respectively. These lines are in the range of selection for resistance to Fusarium head blight disease due to mean disease index of less than 12.5%. While the disease incidence of these lines under the field conditions was relatively low (14.5-24.3%), they had a high disease severity in the greenhouse (92.6-100.0%). Considering that disease incidence under field conditions and disease severity in the greenhouse are indicating type I and type II resistances, respectively, the above-mentioned finding may indicate that the nature of the resistance in these lines is mainly related to type I resistance.