XVI International Botanical Congess

Persistence of Lotus corniculatus is affected by growth dynamics of seed, seedlings, and vegetative and reproductive plants in a field population. Recently, stage-based matrix population models were used to evaluate effects of weather and Rhizoctonia blight on L. corniculatus plantings. Models clarified relative contributions of reproduction and mortality of plants at different growth stages that determine persistence or extinction of populations. Resistance of L. corniculatus populations to Rhizoctonia blight is being correlated with constitutive and, salicylic acid-inducible expression of plant disease defense [PDD] genes [including chitinases, PPO and peroxidases]. Tested populations are segregating for regulation of expression of these genes. Using chitinase as a marker, individuals are being selected that produce elevated levels of PDD components.