III. Seed-yield relationships of Lupinus angustifolius cv. ‘Unicrop’

摘要

Abstract In an August (1976) sowing of Unicrop (Lupinus angustifolius) at 7 plant densities (10–163 plants/m2) seed yield increased to a maximum of 575 g/m2 at 130 plants/m2. Irrigation during flowering and seed-filling reduced seed yield because of an unidentified root pathogen. A maximum leaf area index of 7 was reached 1 week after flowring, resulting in a high leaf area duration (LAD) during seed-filling. Mainstem and first-order pods per unit area accounted for most of the variation in seed yield (r = +0.84*** and +0.77*** respectively). Compensatory branching at lower plant densities did not occur. Irrigation reduced mainstem pod set on disease-free plants, but the yield loss was compensated for by increased production by branches. Increased vegetative growth of irrigated plants also lowered seed set on the mainstem but improved seed set in third- and fourth-order pods Seed number per pod and seed weight decreased at higher inflorescence orders. Seed number per pod was also reduced at high plant den...