بررسي شاخص هاي ارزيابي لاين هاي گندم از نظر مقاومت به فوزاريوم سنبله

Study of different indices for evaluating wheat lines for resistance to Fusarium head blight

Seven homozygous wheat lines representing different levels of resistance to Fusarium head blight were evaluated under infection and normal conditions in a field experiment at Gholestan Province during 2001. Under infected condition, disease incidence (DI), disease severity (DS), disease index (DIX), area under the disease progress curve (AUDPC), grain yield and its components, while under non-infected condition only grain yield and its components were recorded. Genotype as well as genotypexenvironment interaction effects were significant for all the studied indices. Mean comparisons revealed heterogenous trend in responses to infection measured by the different indices. Disease index (DIX) and its AUDPC could not differentiate susceptible from moderately susceptible and resistant from moderately resistant lines. Grain yield and number of kernels per spike had similar shortcomings as Dl and its AUDPC. In general, considering all parameters, 1000 grain weight, DS and its AUDPC were regarded as better indices to differentiate resistant from susceptible lines and to recognize different types of resistance.