Assessment of the seedling resistance of spring wheat lines to Fusarium culmorum
Wheat diseases are one of the constraints limiting wheat yields wherever the crop is grown. Fusarium crown rot, incited by Fusarium culmorum, is one of the most important diseases limiting wheat yields especially in dryland areas. Although there are no wheat varieties which are fully resistant to crown rot, the use of varieties showing some degree of resistance is the most reliable and cost effective method to control this disease. In this study, seedling reactions of 165 spring wheat breeding lines (Triticum aestivum L.) obtained from CIMMYT, Mexico were determined under growth room conditions using an aggressive isolate of Fusarium culmorum. Crown rot severity was assessed using a 1-5 scale. The mean disease severity scores for the lines tested ranged from 1.4 to 4.4. Two out of the 165 lines tested (lines 147 and 158) were resistant (R) in their reaction and had scores of 1.4. Twenty lines showed moderately resistant (MR) reaction and had scores ranging from 1.6 to 2.4. The scores of both the R and MR lines were not significantly different from scores of MR control cultivars. Sixty-three percent of the lines were moderately susceptible (MS). Out of the 165 lines tested, 39 were susceptible (S) in their reaction. The promising wheat lines that showed some degree of resistance to Fusarium culmorum in the present study can serve as useful sources of genetic resistance in breeding for Fusarium crown rot.