Abstract:

In order to investigate the impact of different disease grades of sesame stem rot on individual plant yield and traits, this study compared paired data between diseased plants and control plants under natural disease comditions. The results showed that the first grade diseased plant had a 2.09% reduction in production compared with the control, the second grade reduced production by 21.76%, the third grade reduced production by 23.28%, and the fourth grade reduced production by 67.49%. There was a highly significant correlation between the yield decline rate of all diseased plants and the severity of the disease. As the grades of sesame stem rot increased, the rate of yield loss per plant, capsule number reduction rate, effective capsule reduction rate, thousand grain weight reduction rate, plant height reduction rate, and fruit node number reduction rate increased. For these six traits, there was no significant difference between the first grade diseased plant and the control. The difference between the fourth grade diseased plant and the control was extremely significant and the decrease rate of the above traits of the first grade diseased plant and that of the fourth grade diseased plant all reached significant or extremely significant differences. The decrease in capsule number plays a decisive role in the reduction of yield per plant. The decrease in thousand grain weight caused by smaller grains may play an important role in the decrease of yield per plant at specific disease grades. This study provides a basic condition for estimating population yield.

Key words: sesame stem rot, disease grades, individual plant yield, trait