Morphological and Physiological Parameters of Soybean Resistance to Agromyzid Beanflies

Four soybean varieties which are highly resistant to agromyzid beanflies and two beanfly-susceptible varieties were grown under conditions which simulated those of the fall crop season in Taiwan. Morphological and physiological parameters of the plants with beanfly resistance versus susceptibility were compared. The observed data from the Biotron study were then correlated with those on beanfly infestation in Taiwan. A multiple correlation analysis showed that during the early plant growing stages, the beanfly infestation seems to be influenced especially by the trichome density of the under (abaxial) surface of leaves, leaf area, leaf moisture content, and stem diameter. When a plant is in the V 3 stage of growth or older, both the leaf dry weight per cm 2 of the second trifoliate leaf and stem moisture content of the internode between the second and third nodes also are positively correlated with the level of beanfly infestation.