Physiology of growth and seed production in Lupinus angustifolius L. II. Effect of temperature before and after flowering

Abstract

Plants of Lupinus angustifolius cv. Unicrop, with branches excised to eliminate competition between branches and the primary inflorescence, were raised at 21/16¦C and transferred as flowering began to eight temperature regimes from 36/31 to 15/10¦C for seed development. Vegetative growth rather than seed growth was stimulated by coolest conditions, although ultimate individual seed weight was greatest at the lowest temperatures. Plant growth was poor at temperatures above 27/22¦C. Temperatures about 21/16¦C were most suitable for seed development. In another experiment, plants with branches excised were grown at 27/22 or 18/13¦C until flowering, when they were either retained in the same conditions or moved to the other. Conditions before flowering determined growth of the inflorescence for the first 24 days after flowering began, but conditions after flowering affected ultimate yield. Plants raised to flowering at 27/22¦C were able to recover if exposed to 18/13¦C after flowering. This suggested a possible role for lupins as an autumn crop where water is available.