RESPONSES OF WILD AND CULTIVATED BARLEY FROM WEST ASIA TO NET BLOTCH AND SPOT BLOTCH

Wild species and cultivated landraces from the center of crop origin m ay provide new sources of resistance to a variety of plant diseases th at plague genetically uniform crops around the world. This study was c onducted to assess resistance to Canadian isolates of three foliar pat hogens [Cochliobolus sativus (Ito and Kurib.) Drechsl. ex Dastur., Pyr enophora teres (Died.) Drechsl. f. teres, and P. teres, f. maculata] i n wild and cultivated landrace barley [Hordeum vulgare L. subsp. spont aneum (C. Koch) Thell. and H. vulgare L. subsp. vulgare] from Turkey a nd Jordan and to determine whether disease resistance was preserved by in situ conservation of the two barley species. Seedlings were inocul ated separately with the pathogens in growth cabinet tests. More wild barley accessions were resistant to C. sativus (4.5% vs 0.3%) and P. t eres f. teres (21.8% vs. 0.5%) than cultivated barley. An equal number of wild and cultivated barley accessions was resistant to P. teres f. maculata. A larger percentage of wild barley accessions (10.5%) had a t least moderate resistance to all three leaf diseases as compared to only 1.3% in cultivated barley. The average disease rating on these ac cessions was lower for wild barley (65%) but not significantly differe nt from cultivated barley (73%). Chi-square statistics showed signific ant associations for disease reactions of (i) C. sativus with P. teres f. maculata, and (ii) P. teres f. teres with P. teres f. maculata tha t were larger in cultivated barley, indicating stronger associations d ue to agricultural selection. Disease reactions were independent for C . sativus and P. teres f. teres In both wild and cultivated barley. In situ conservation of cultivated barley in the Middle East was success ful in preserving resistance in either single or multiple combinations in cultivated landrace populations, but it was less effective in pres erving the diversity for resistance than in wild barley.