Seasonal and irrigation effect on yield parameters and soluble solids content of processing cherry tomato

Cherry-type tomato for processing with determinate growth habit and increased solid content is a new perspective in improving tomato product quality. A 5-year (2010-2014) open-field experiment was conducted to study the effect of different water supply on yield components (yield, fruit number per hectare, average fruit weight and soluble solids) of 'Strombolino' F1, a cherry-type processing tomato. The seasonal effect of the 5 years was significant, because the precipitation totals were different in each year. Calculated optimum water supply by irrigation (I) was compared with a rainfed control (C). Regularly irrigated plants were irrigated with the calculated amount of water from the beginning of June to the end of July. The water supplied to crops was 500, 489, 596, 344, 521 mm in I, and 351, 153, 219, 163 and 353 mm in C treatments, respectively, during the five seasons. The seasonal effect of the 5 years was significant because, of the last 100 years, the rainiest season was 2010, and the driest season was 2011. Irrigation had a greater effect on the average fruit weight (R-2= 0.57) than on fruit number (R-2= 0.0003) because of the limited number of flowers in the determinate growth habit of processing tomatoes. Seasonal variations in yield occurred mainly in the harvestable fruit number, and it was influenced significantly by weather during the flowering period. The irrigated plants gave a significantly higher marketable yield, compared with rainfed plant stands. We observed a positive correlation between water supply and total marketable yield. Increasing water supply increased fruit yield, but significantly reduced soluble solids (dilution effect); nevertheless, the overall effect of irrigation was an increase in soluble solids yield, because of the high correlation (R-2= 0.95) between yield and soluble solids yields.