DENSITY STUDIES ON LUPINS .2. COMPONENTS OF SEED YIELD

Components of seed yield of cv. Ultra (Lupinus albus L.) and cv. Unicrop (L. angustifolius L.) were measured when grown at three densities. The low density (10 plants m-2) Unicrop yield (34 g seed per plant) was 1.8 times that of Ultra as it had more branches, pods and seeds per pod. Ultra seeds (310 mg per seed) were heavier than Unicrop seeds (180 mg). The branching pattern of Ultra was less dependent on plant density, hence at 93 plants m-2 it gave a higher per plant yield (7.4 vs 6.4 g) than Unicrop at lower densities (83 plants m-2). Density had most influence on pod formation and only small effects on seeds per pod and seed weight. Yield components on the main-stem inflorescence were influenced less by density than components on branch inflorescences. Later formed, higher order generations of inflorescences were most affected by increased inter- and intra-plant competition. Pod numbers on the main-stem were similar for both species. Pods formed at higher flower nodes in Unicrop, but the lower flower nodes were less fertile than those in Ultra. Node position of flowers had no influence on seed set in main-stem Unicrop pods, but pods from higher nodes in Ultra formed fewer seeds. Seed weights in Unicrop were similar among main-stem nodes but in Ultra seed weights tended to increase at higher nodes. © 1979, Annals of Botany Company.