Effects of growing system and season on the alkaloid content and yield of different sweet L. angustifolius genotypes

Nine varieties and two breeding lines of sweet Lupinus angustifolius were cultivated under organic and conventional conditions in Northern Germany in growing seasons 2010, 2011 and 2012. The alkaloid content was significantly influenced by the growing system and year and also by genotype. The variety `Vitabor` and the breeding line Bo 083521AR revealed a very low alkaloid content in all years and cropping systems, while `Sanabor`, `Borlu` and `Boregine` had a higher content. In the years 2010-2012 significantly lower alkaloid contents (475 µg/g) were found under organic conditions than under conventional conditions (615 µg/g). The mean alkaloid level of all varieties and breeding lines in organic farming was highest in 2010 (640 µg/g) and lowest in 2012 (364 µg/g), depending on temperature during the seed filling period. Investigations on the yield of L. angustifolius revealed significant effects of the genotype, the year and the growing system.