LIGHT INTERCEPTION AND DRY-MATTER PRODUCT ION OF A CONVENTIONAL AND AN EPIGONAL GENOTYPE OF THE WHITE LUPINE (LUPINUS-ALBUS)

Yield formation of two white lupin (Lupinus albus) genotypes differing substantially in growth habit was investigated. Grain production was quantified as the product of harvest index and dry matter production, the latter being a function of light interception and utilization. Exp erimental data were obtained from two-year field experiments with a co mbined variation of plant density and distribution. The conventional, freely branching cultivar Kalina showed higher leaf area indices and g rowth rates than the 'epigonal' (little branching) genotype. The highe r growth rates of Kalina were partly due to increased light intercepti on, but were mainly a result of a higher light use efficiency. This ca n be explained with a more even fight distribution over a greater leaf area. The more rapid increase of the harvest index in the epigonal ge notype compared to Kalina only partially compensated for the differenc es in dry matter production.