THE IMPORTANCE OF HARVEST DATE AND IRRIGATION MANAGEMENT WITH THE USE OF EXTENDED FIELD STORAGE VARIETIES ON YIELD AND QUALITY IN PROCESSING TOMATOES

Harvesting at the optimum date according to crop maturation is difficult to achieve, especially when growers do not have their own harvesters. The use of Extended Field Storage varieties (EFS) keep more fruits red and firm in the field without rotting and cracking allowing late green fruits to complete maturation till harvest. This might mitigate the negative effects of a late harvest date. Irrigation management under drip systems can affect yield and quality, particularly, at the end of the crop cycle before harvest. This study focused on the effect of harvest date and the irrigation management after initial maturation of fruits on yield and quality of production by the use of EFS varieties. Trials were conducted in La Consulta INTA Experimental Station in Mendoza, Argentina during seasons 2012-2014. The crop beds were separated 1.5 m apart with single drip tape, emitters spaced 0.3 m in the line, 2.2 mm.ha^-1.h^-1. Daily water replenishment was done according to evapotranspiration by type A tank adjusted by kc. Varieties of different EFS characteristics were used: Non EFS Star 9063 (Starke Ayres) and PS 2461838 (Monsanto), EFS HM 3861 and HM 7883 (Harris Moran). In one trial, three harvest dates were considered: 105, 120 and 135 days after transplanting (DAT). In another trial, four different irrigation managements were established after first red fruit appearance in the plant: 100, 75, 35% and no water replenishment according to ETc and kc. Non EFS varieties had significantly less marketable yield in the late harvest date (135 DAT). Rots percentage had a significant variety × harvest date interaction; non EFS varieties had more rots after early harvest (105 DAT). Soluble solids were not significantly affected by harvest date. Acidity was significantly reduced by harvest date. Both EFS and non EFS had similar pattern by different water replenishment.Total water replenishment (100% ETc) till harvest tends to increase yield, greens and reduce soluble solids. Rots were affected in non EFS on high water stress replenishment (35% ETc) in one year. It was concluded that EFS varieties assure growers better yields and quality when harvests are delayed, rots are the main quality defect observed in non EFS varieties.