IS THERE A COST FOR WHEAT CULTIVARS WITH GENES FOR RESISTANCE TO YELLOW RUST CAUSED BY PUCCINIA-STRIIFORMIS

Eight bread wheat lines, showing a wide response to yellow rust, were intercrossed in all combinations to provide F-1 and F-2 diallels for a ssessing disease incidence and its effect on yield and related charact ers at low- and high-rust locations in Uganda. Average yield loss over the trial period at the high-lust site due to all foliar diseases was 83%, of which yellow rust accounted for 25%. Rust resistant material outyielded susceptible material in control plots untreated with fungic ide by 138%. At the low-rust location, resistant and susceptible mater ial had comparable yields within treated and control plots, indicating that no significant yield loss was incurred by growing resistant mate rial in the absence of rust pressure. (C) 1998 Elsevier Science Ltd. A ll rights reserved.