Correlation of the alkaloid content and composition of narrow-leafed lupins (Lupinus angustifolius L.) to aphid susceptibility

Abstract

Breeding of narrow-leafed lupins (Lupinus angustifolius L.) with a low alkaloid content, so called sweet lupins, increased the use for food and feed. Coincidentally, the reduced alkaloid content increased the susceptibility for aphid infestation. Hence, breeding of resistant cultivars is needed to prevent yield losses and reduce the application of insecticides. As a prerequisite for this, the evaluation of a diverse collection of narrow-leafed lupin genotypes is needed. Therefore, the multiplication of different aphid species, i.e., Macrosiphum albifrons, Aphis fabae, Aphis craccivora, Acyrthosiphon pisum, and Myzus persicae (all Hemiptera: Aphididae) was investigated on 46 narrow-leafed lupin genotypes under controlled conditions. Furthermore, the alkaloid composition and total content of these genotypes was analyzed, in order to get information on their influence on the susceptibility to different aphid species. Results indicated that the multiplication of the well-adapted lupin aphid (M. albifrons) is not affected by the alkaloid content. In contrast, A. fabae, A. pisum, M. persicae, and A. craccivora showed a negative correlation between aphid multiplication and alkaloid content (r = −0.493 to −0.350). However, several genotypes with a low total alkaloid content, e.g., Kalya, Bora, and Borlu, were detected on which no or only a very limited aphid multiplication was observed, indicating that not only the total content, but also the alkaloid composition is influencing aphid development. By multiple linear regression analysis, it turned out that especially 13-hydroxylupanine and 13-tigloyloxylupanine are involved in the reduced aphid multiplication rate. Respective genotypes may be the starting point for diminishing aphid susceptibility in sweet lupins.