Yield and quality of processing tomato varieties, as raw and canned product, with relation to irrigation level

The study was based on the assumption that even limited over-irrigation, as often practised in most leading farms of a major tomato production area of Southern Italy, is detrimental to the yield and particularly to the quality of fresh and canned product. Four irrigation treatments were tested, ranging from a 'wet' control (similar to the irrigation regime adopted in many farms) to a 'dry' treatment receiving a single watering. In terms of average depth the total water given ranged between about 60 and 10 cm. The experiment was conducted in two sites during 1983 and 1984 on four varieties: 'Novamech', 'Rio Fuego', 'T2' and 'Sole 22'. Data on soil moisture profiles during the crop cycles were recorded. When about 90% of the fruits were ripe, an once-over mechanical harvesting was simulated. Yield and field discard percentage were recorded; the commercial product was then sent to the processing plant of the Station for Food Preservation where it was tested and analyzed both as raw and, after processing, as canned product. The treatments were also evaluated globally by quantitative and qualitative indexes. The results confirmed that high irrigation levels do not increase the yield but depress the quality of the product. Suggestions are given on the efficient management of tomato irrigation.