Narrow-leafed lupins with restricted branching

Crop phenology is one of the most important characters influencing producti vity in a given environment. Narrow-leafed lupin (Lupinus angustifolius L.) is a major grain legume crop in southern Australia with general phenologic al adaptation to this Mediterranean-type environment. However, it is an ind eterminate crop with several associated limitations to productivity, such a s overlapping vegetative and reproductive growth, late grain filling and so metimes excessive vegetative growth. Here we studied two novel types of nar row-leafed lupin with restricted branching, which might be useful for overc oming these problems. These restricted branching lupins arose spontaneously within a breeding population, in the case of 'Tallerack', and within a far mer's crop in the case of 'Hurst' and we compared them with the 'Merrit'. w hich is widely grown and has the normal indeterminate branching habit. The morphology and development of the main shoot of these genotypes were simila r. However, 'Hurst' had much larger leaves. There were also striking differ ences in the lateral branches of the restricted branching types; they had f ewer leaves than 'Merrit' acid flowered earlier. These differences were mos t marked in 'Hurst', where the upper main stem branches were reduced to a s ingle floret in the axil of main stem leaves, and these flowers often exhib ited abnormal morphology. (C) 2000 Annals of Botany Company.