Field environment studies on lupins. I. Developmental patterns in Lupinus angustifolius L., the effects of cultivar, site and planting time

Abstract

The development of early (Unicrop) and late (Uniharvest) flowering cultivars of Lupinus angustifolius was studied with eight planting times at two climatically contrasting sites representing the main lupin-producing areas in Western Australia.

Differences in time from planting to floral initiation and from initiation to first flower, in duration of flowering, and in time of maturity were measured. The major differences in phasic development between the cultivars for the different planting times and sites were for the period from planting to initiation. This is explained in terms of the known vernalization requirement of Uniharvest. As a consequence, initiation of the two cultivars was closest with midwinter planting in the cool environment and farthest apart with eariy planting at the warmer site. For comparable planting times the differences between cultivars for the period from initiation to first flower were small. Duration of flowering and final maturity were mainly influenced by the definite end to the growing season brought on by moisture stress and high temperatures.

Differences in photoperiod exerted little influence on development.

Growth of the plant was indeterminate, but the presence of terminal inflorescences on the main axis and branches produced a series of easily identified orders of lateral branches. Inflorescences flowered in sequence, extending the duration of flowering as successively higher orders of laterals were formed. Late planting reduced the length of all growth phases but drastically reduced the duration of flowering.

The results are discussed in relation to the Western Australian environment, and it is argued that, in such environments, indeterminate growth has potential adaptive advantage over the determinate growth pattern of the cereals.