Influence of year, genotype and cultivation system on nutritional values and bioactive compounds in tomato (Solanum lycopersicum L.)

Two tomato genotypes were grown in open field by three cultivation systems (one conventional and two distinct organic for mulching) in three years, 2015, 2016 and 2017. Yields, sugars, organic acids, amino acids, ascorbic acid, biothiols, carotenoids and phenols were measured. Weather conditions largely differed among harvest years, with summer 2016 rainier and less warm, and an opposite summer 2017. Organic systems had lower yields than conventional one but also, interestingly, lower waste percentages. Furthermore, tilled and no-tilled organic systems provided comparable yields. With respect to 3-year average, sugars were higher in 2017, acids in 2016 and in organic fruits, and amino acids increased in 2015 and in conventional samples. A higher glutathione content was found in organic samples, and higher carotenoids in 2017. Phenols increased in 2016, with a higher chlorogenic acid content in organic tomatoes. Some differences between genotypes were observed, highlighting their different adaptability to growing systems.