Restricted branching narrow-leafed lupin. 3. Poor establishment

Abstract

Establishment of restricted branching narrow-leafed lupins (Lupinus angustifolius L.) is often poorer than that of the normal branching counterparts. This study focused on establishment of the cultivars Tallerack and Merrit, as representative of restricted and normal branching lupins, respectively. Establishment from seeds of both genotypes harvested manually was high, but machine harvesting decreased establishment, at some sites markedly, and generally more so in Tallerack than in Merrit. Establishment problems were related to germination and not emergence or seedling vigour. A similar contrast was found when seeds were harvested from several near-isogenic pairs of restricted- and normal branching genotypes. The basis of the generally greater sensitivity of the restricted branching genotypes to harvest damage, and the interaction with environment is not clear. It is not related to differences between genotypes in the seed size, proportion of hull in seeds or seed moisture content, but hull composition and embryo morphology warrant further study. Irrespective of its basis, higher harvest damage to seeds of restricted branching genotypes is likely to be avoided by minimising harvester drum speeds and harvesting at higher seed moisture concentrations.