Relationship between almond bitterness and resistance to capnode

Abstract

Capnode (Capnodis tenebrionis L.) is one of the main pests that affect fruit trees in the Mediterranean basin and other semi-arid areas around the world. Some studies seem to show a relationship between kernel bitterness, presence of cyanogenic compounds in roots and resistance to capnode. In this work we studied prunasin content and the resistance to capnode grubs of almond descendants of different genotypes with respect to bitterness: SS (sweet) ['Peraleja' (SS) x 'Ramillete' (SS)]; ss (bitter) [S3064 (ss) x S3067 (ss)] and Ss (sweet or slightly bitter) [S3064 (ss) x 'Ramillete' (SS)]. Three months after having inoculated the plants with neonate grubs, incidence of damage in roots and presence of grubs were determined. Afterwards, prunasin content in the roots was determined by HPLC. The results showed that the damage level was similar in the three families. The prunasin contents seemed to be independent of kernel bitterness and behaved as a quantitative trait. The lack of relationship found between prunasin contents and damage in roots might be due to an anomalous low incidence of capnode grubs in the roots.