Narrow-leafed Lupins with Restricted Branching

Crop phenology is one of the most important characters influencing productivity in a given environment. Narrow-leafed lupin (Lupinus angustifolius L.) is a major grain legume crop in southern Australia with general phenological adaptation to this Mediterranean-type environment. However, it is an indeterminate crop with several associated limitations to productivity, such as overlapping vegetative and reproductive growth, late grain filling and sometimes excessive vegetative growth. Here we studied two novel types of narrow-leafed lupin with restricted branching, which might be useful for overcoming these problems. These restricted branching lupins arose spontaneously within a breeding population, in the case of ‘Tallerack’, and within a farmer's crop in the case of ‘ Hurst’ and we compared them with the ‘Merrit’, which is widely grown and has the normal indeterminate branching habit. The morphology and development of the main shoot of these genotypes were similar. However, ‘Hurst’ had much larger leaves. There were also striking differences in the lateral branches of the restricted branching types; they had fewer leaves than ‘Merrit’ and flowered earlier. These differences were most marked in ‘ Hurst’, where the upper main stem branches were reduced to a single floret in the axil of main stem leaves, and these flowers often exhibited abnormal morphology.