EFFECT OF GROWTH STAGE ON RESISTANCE TO DRECHSLERA-TERES F TERES IN BARLEY

Three experiments were conducted to evaluate seedling: and adult plant resistance to Drechslera teres f. teres in barley lines with a potent ial use as resistance sources in barley breeding. Disease resistance o f barley seedlings, inoculated in the glasshouse and growth chamber at the one- and two-leaf stages, was significantly (P 0.05) correlated w ith disease reactions on the fourth and flag leaves of barley plants g rown in growth chambers (r = 0.84-0.94) as well as with disease levels recorded on the three uppermost leaves in a field experiment (r = 0.6 4). Several of the barley lines showed no correlation, demonstrating e ither improved or decreased disease resistance at later growth stages. Six barley lines (Alexis, Heartland, Kinnan, CI4922, CI9776 and SW111 4-93) had the same ranking in disease resistance to D. teres when dama ged (punctured) leaves were inoculated with a drop of spore suspension as when undamaged leaves were spray-inoculated with a spore suspensio n.