استجابة بعض الطرز الوراثية من القمح الطري لمرض الصدأ المخطط المتسبب عن فطر Puccinia striiformis west f. sp. tritici في العراق

Abstract EN

Response of some Triticum aestivum L.

genotypes to Puccinia striiformis west f.

sp.

tritici were studied for two seasons (1994/95 and!995/96) at Rashidia Station (Mosul).

Artificial inoculation was done with uredosporc suspension of P.

striiformis at stem elongation stage (Peeks 9-10).

Disease severity and infection type were recorded periodically at different stages of plant development.

Results revealed that during the two seasons the genotypes expressed different degrees of resistance and susceptibility.

They also showed variation in the infection rate and the area under the disease progress curves (AUDPC).

Higher values of disease severity, infection type and infection rate were observed on Saber Beg, while the lower values were registered on Intsar.

The data showed that the stripe rust caused grain yield loss between 5.7% in Intsar to 45.9 in Saber Beg.

Yield loss was due to the significant effect of the disease on thousand grain weight and number of grains per head.

Significant correlation at P_> 0.01 between the area under the disease progress curve and yield loss was found.