Developing Predictive Models under Controlled Conditions for the Selection of New Genotypes That Are Less Susceptible to Bactrocera oleae (Rossi) in Table Olive (Olea europaea L.) Breeding Programs

Abstract

Bactrocera oleae (Rossi), the olive fly, represent an important biotic factor in olive groves (Olea europaea L.) causing significant production losses. Ensuring effective management of this pest is of paramount importance to safeguard and uphold the quality and quantity of table olive production. The University of Seville’s (US) table olive breeding program has focused its attention on finding new cultivars that exhibit reduced susceptibility to the olive fly. This study attempted to develop predictive models to enable the selection of new genotypes that are less susceptible to the olive fly based on fresh fruit traits. An extensive analysis of fruit physical (weight, size, symmetry, color, and texture) and chemical traits (moisture, oil content, and phenolic compounds) was conducted to evaluate the fly’s preference in oviposition bioassays (multiple choice and no choice) among four genotypes (US-06-1388, US-06-194, ‘Hojiblanca’, and ‘Kalamon’), under controlled conditions. The oviposition bioassays revealed the higher susceptibility of genotype US-06-194 and the lower susceptibility of ‘Kalamon’. The predictive models incorporated physical traits such as, fruit weight, longitudinal diameter, symmetry, CIELAB color attributes (L*, a*, and b*), and compression hardness, as well as chemical traits such as moisture, and the contents of demethyloleuropein, oleuropein, rutin, and verbascoside. These traits consistently predicted the preference of B. oleae for certain fruits