Significant interactions between wheat and lupins occur below ground and wheat intercropped with lupins has access to a larger pool of available P, Mn and N than has wheat grown in monoculture. This suggests that the wheat is able to take up nutrients produced or made available by lupins grown in association with it.

The effect of serial planting on the phenological development of Lupinus angustifolius (cvv. Uniwhite, Uniharvest and Unicrop) and L. albus (cv. Ultra) was investigated in field plots at north-eastern Victoria. In 1973, Uniwhite was sown at 16 weekly intervals from May to September at one site: in 1974 Uniharvest, Unicrop and Ultra were planted at four locations, from early April to late September. Duration of the developmental phases-emergence to floral initiation, initiation to first flower, and first flower to last flower-was related to field measurements of temperature, photoperiod, and global radiation. Development of all cultivars from emergence to flowering was highly correlated with temperature and photoperiod (coefficients of determination from 49.5 per cent to 98.5 per cent). Our results suggested that photoperiod contributed to the duration of the flowering period. Unicrop and Ultra were quicker to initiate and flower than Uniharvest and Uniwhite, particularly from early plantings. Later planting reduced the duration of the post-initiation phases, particularly duration of flowering. The range of developmental adaptability exhibited by the four cultivars indicates that lupins could be grown over a large area of Victoria.

In a series of glasshouse and field experiments, the symbiotic characteristics of 24 lines of Lupinus and Ornithopus species and 20 strains of Rhizobium lupini were defined. Rhizobium lupini inoculant established readily in several soils and lupins grown in the field responded to inoculation by improved nodulation, growth and yield. It is concluded that lupin crops sown on new land need to be inoculated to achieve optimum yield. At three sites, field-grown lupins responded to increasing rates of inoculation up to the rate recommended by the inoculant manufacturer. At two of the sites there was no further response to higher rates, but at the third there was a continuing response up to 125x (inoculation rate). Lupin seed was preinoculated, using gum arabic adhesive, up to 33 days before sowing without significant loss of viability or nodulating capacity of the inoculant. Seed coating with several materials did not improve inoculant viability on preinoculated seed. In glasshouse experiments, hostxstrain interactions in nitrogen fixation were frequent and substantial. They occurred at three levels of taxonomic relationship, viz, between the genera Lupinus and Ornithopus, between different species within the same genus, and between different lines of the same lupin species. Hostx strain interactions were also observed in field experiments but were less frequent and smaller than in the glasshouse. These observations have implications for the 'single-strain inoculant policy that applies to the manufacture of commercial lupin and serradella inoculant in Australia.

The effect of serial planting on dry matter production, leaf area, grain yield and yield components cf Lupinus angustifoiius (cvv. Uniwhite, Uniharvest and Unicrop) and L. albus (cv. Ultra) was investigated in field plots at Rutherglen in 1973 and 1974. Delayed planting reduced dry matter production of all cultivars, and leaf area for Ultra. Differences in dry matter partitioning were observed between the late flowering Uniharvest, and the early flowering Unicrop and Ultra. In Uniharvest, delayed plantings resulted in a greater proportion of total dry matter being produced during the flowering phase, whereas the reverse was true for Unicrop and Ultra. The later flowering cultivars showed marked grain yield and yield component reduction with later sowing. Yields were reduced by 160.6 kg/ha and 222.5 kg/ha for each week's delay in sowing Uniharvest and Uniwhite, respectively. This effect was offset in the early flowering cultivars by greater development of lateral branches. In addition, when Unicrop and Ultra were planted in April, pod and flower abortion on the main stem resulted from low temperatures at flowering time. Optimum sowing time was early April for Uniwhite and Uniharvest, and early May for Unicrop and Ultra. Excellent vegetative growth under ideal moisture conditions highlighted the poor harvest indices of lupins and the scope for genetic improvement in the genus.