YIELD FORMATION AND YIELD COMPONENTS OF A CONVENTIONAL AND AN EPIGONAL GENOTYPE OF WHITE LUPIN (LUPINUS-ALBUS)

Differences in yield formation and yield structure of two contrasting Lupinus albus growth types, the conventional, freely branching cultiva r Kalina and the epigonal, little branching cultivar Ep I were analyze d. Both cultivars were grown in field experiments at Hohenheim in 1987 and 1988 with a combined variation of population density (30-120 plan ts/m2) and plant distribution. In addition, assimilate distribution wi thin the plant was studied using a C-14-labelling experiment. - The co ntributions of branches to light interception of the crops during the generative phase were > 90 % in Kalina as compared to about 30 % in Ep I. Relative C-14 uptake of branches was in a similar range, but great proportions of the C-14 taken up by branches was translocated to main stems. No genotype x plant density interactions with respect to grain yield were recorded, indicating that yield formation at main stems an d branches was affected by cropping conditions similarly in both genot ypes. This applies to the conditions of the experiments, where stress effects were absent. Under these conditions, the conventional genotype showed agronomic, but no physiological disadvantages.