Agronomic studies on Lupinus angustifolius in Western Australia: effect of cultivar, time of sowing and plant density on seed yield

Abstract

The results of 28 experiments with sweet lupins (Lupinus angustifolius) over five seasons, in the temperate agricultural area of Western Australia south of the 29¦ latitude, indicate that the correct time of planting and variety is influenced by length of the growing season. Broadly, in the agricultural area north of Perth the early flowering cv. Unicrop sown in May gave 50 per cent higher seed yield than either Uniharvest lupin or later sowing. In the cooler area south of Perth, the effect of later sowing on seed yield was as marked, but only when it was delayed until July, when reproductive development was severely restricted. Due to the lower temperatures in the southern area there was little difference in yield between Unicrop and Uniharvest. Although there was a marked influence of plant density on seed yield, the results were inconclusive because of the failure in the majority of experiments to achieve densities at which the yield peaked and then declined. Where this was achieved there was great variation in the level of density required for maximum seed yield because of site and seasonal differences. Three experiments suggested that greater plant density will help compensate for a loss in seed yield per plant with later sowing.