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POSTERS: Biochemistry and cell biology

Silverleaf effects on plum fruit yield and quality
Daina Grinbergs - INIA Quilamapu. Andres France- INIA Quilamapu, Marisol Reyes- INIA Quilamapu, Javier Chilian- INIA Quilamapu, Carla Hahn- INIA Quilamapu, Jorunn Borve- Norwegian Inst of Bioeconomy Res

Silverleaf, caused by the basidiomycete Chondrostereum purpureum, is an important disease which affects fruit trees producing wood necrosis and foliar silvering, due to the activity of an endoPG enzyme. It deteriorates plant physiological conditions by altering photosynthesis, reducing fruit quality and yield, like in apple (60%) and blueberry (40%). The objectives were to assess the effects of endoPG on fruit yield and quality in a commercial plum orchard. A 4-year old orchard of Prunus domestica cv. Angeleno was assessed by evaluating 20 symptomatic and 20 asymptomatic plants. The presence of C. purpureum was determined based on pathogen isolation on culture media, ELISA test, and PCR. Physiological parameters such as water potential, fluorescence, chlorophyll content and stomatal conductance were measured. Moreover, total yield, caliber, soluble solids, titratable acidity, firmness, colour and defects on fruit were evaluated. The results indicate the fungus was present in all the trees, however, in symptomatic ones the endoPG levels in foliage was greater. All the physiological parameters were altered in symptomatic plants, being water uptake and chlorophyll content the most affected ones. Fruit yield reduction in symptomatic trees was 51% compared to asymptomatic ones, being caliber, cover colour and firmness the most affected traits. Consequently, endoPG level is determinant in the yield and fruit quality reduction in plum.