Abstract
The rust epidemic on a susceptible cultivar progressed more rapidly than on a tolerant cultivar. Defoliation increased rapidly after 50% pod fill. The reduction of the LAI (leaf area index) in the susceptible cultivar occurred earlier than in the tolerant cultivar. The reduction in the chlorophyll content between the healthy and rust-infected plants was 2.04% in the tolerant, and 16.3% in the susceptible cultivar. The shoot dry weight increased in the fungicide-protected plots, but decreased in the nonfungicide-protected plots after the R6 growth stage, and the tendency to decrease was more severe in the susceptible than in the tolerant cultivar. The pod and seed dry weight of the susceptible cultivar in the fungicide-protected plot increased dramatically from the R6 growth stage; in the nonfungicide plot there was almost no increase in pod and seed dry weight. In the tolerant cultivar, the pod and seed dry weight was less affected than in the susceptible cultivar. The number of empty pods and imperfect seed increased with rust infection, but the protein content was not affected. There were reductions in oil content, seed length, seed width, seed thickness, pod thickness, number of pods and seeds, 100 seed-weight, and yield due to infection. These reductions were greater in the susceptible cultivar than in the tolerant cultivar. The yield losses were 22% in the tolerant and 69% in the susceptible cultivar. [AS/EMS]