COMPOSITIONAL QUALITY ANALYSES AND RESPONSE TO BOTRYTIS DISEASES OF DIFFERENT STRAWBERRY GENOTYPES

The strawberry is an infructescence that belongs to the Rosaceae family, a perennial plant mistakenly considered to be of the herbaceous type. Strawberry is one of the most cultivated and widespread fruits in the world and represents an important source of income for many countries, including Italy. Europe remains one of the main production areas, where most of the production is concentrated in Spain and Italy. In Italy, in 2020 the cultivated areas to produce strawberries amounted to 3646 ha (in decrease of 4% compared to 2019), with an annual production of around 130,000 t. The Italian strawberry cultivation is mainly concentrated in the southern territories. Basilicata, Campania and Sicily represent about 50% of the total cultivated areas, while the complex of the 4 major northern regions slightly exceeds 22%. Strawberry is a highly perishable fruit, characterized by a short shelf-life, which can be affected by numerous pathogenic species, such as fungi, bacteria, viruses and nematodes. The development of the disease can lead to the reduction in the commercial quality of the product, the development of numerous damages and, in the worst cases, even the death of the plant. The most economically important pathogens of strawberry are fungi, and in particular the ascomycete Botrytis cinerea of the Sclerotiniaceae family, responsible for causing severe economic losses to the strawberry industry. To date, there is no variety that is immune or tolerant to the fungus. In the modern production, one of the most common management practices used for the prevention of postharvest rot is the use of fungicides, which are applied several times on the canopy of strawberry plants. However, the concern related to the presence of residues by the population, the growing resistance of the fungus and the legal restrictions related to the use of chemicals, have led to advanced studies to find new alternatives. Numerous studies are evaluating the best less susceptible varieties on the market and experimenting new field instruments that can allow the identification of the disease directly in the field. Future research does not exclude the possibility of genetic modification and breeding techniques to produce commercial varieties characterized by a higher B. cinerea tolerance. Furthermore, the growing attention on qualitative and nutritional parameters, such as sugar content, acidity, and the content of bioactive substances, has led to an in-depth study of the varieties affected by the disease. Some studies were focused on the response to botrytis disease, on how the nutritional and qualitative content varies, to find the best and most resistant varieties, and to obtain high quality products. The most used techniques to measure the parameters mentioned above can be destructive and non-destructive. The High-Performance Liquid Chromatography is a destructive method which therefore involves the loss of integrity of the fruit. However, is an easy-to-use tool that allows to investigate a wide range of substances, achieving complete separation of a mixture of compounds in a relatively short time. For the present study, four well-defined strawberry cultivars (Romina, Cristina, Silvia and Sibilla) were selected in the 2020 harvest season and tested under treatment with Botrytis cinerea, the fungus that causes gray mold. The aim is to determine the nutritional and qualitative changes, evaluating the content of soluble solids, titratable acidity, the content of vitamin C and phenolic acids; and to evaluate the response and susceptibility of each cultivar, in response to the disease caused by the fungal pathogen.