Abstract
Soybean cotyledons were artificially removed to simulate the damage taken by the rufous turtle dove, Streptopelia orientalis (LATHAM), and the yield of soybean was estimated from the results obtained here and the data on intensity of soybean damage caused by doves obtained another experiment. The more the number of cotyledon cutting and the sooner the timing of cutting, the severer the effect on growth. In the early growth stage of plant there were significant differences in measurements between the control and damaged soybeans, but there were minor or no differences in the later stage. The value for the number of branches, nodes, and leaves of damaged soybean recovered relatively in the early stage, but those of stem length and plant weight did later. In the variety of early ripening the harvest sometimes became before the recovery completion of growth. There were major effects of removed cotyledons on the crop of the early-ripening variety and minor or no on later-ripening variety. The yields of soybean (variety Enrei) were estimated to be 26% to that of the control if plants were damaged heavily at the stage of just after the germination, 53% at cotyledon spreading, 73% at just after cotyledon spread, 99% at primary leaf spreading and 99% at just after primary leaf spread. Therefore we need to avoid the damage due to doves from the time just after sowing to primary leaf spreading.
