Effect of Deficit Irrigation on Total Yield, Fruit Physical Characteristics, and Nutritional Value of Four Drought Tolerant Tomato (Solanum lycopersicum L.) Genotypes

Water deficit is a major factor limiting plant water productivity and fruit quantity and quality, particularly in arid and semi-arid regions of the world. The total yield, fruit physical characteristics, and nutritional value of four drought tolerant tomato genotypes (KSU-TOM- 102, KSU-TOM-106, KSU-TOM-107 and TL–01860) were evaluated in response to deficit irrigation (DI) under field conditions. Three levels of crop Evapo- Ttranspiration (ETc; 50, 75, and 100%) were applied at three different growth stages (vegetative, flowering, and fruiting) to the four tomato genotypes. Tomato genotypes differed in their responses to water deficit. Among different genotypes, KSU-TOM-102 recorded the highest average total yield (89.54 t ha^-1) under irrigation treatment with 100% of ETc during all stages as well as 75% of ETc during the fruiting stage. However, in general, total yield decreased under water deficit. Fruits quality characteristics were significantly (P≤ 0.05) affected by irrigation water treatments, tomato genotypes, and their interactions. Irrigation with water at 50% ETc at all growth stages significantly (P≤ 0.05) increased vitamin C, titratable acidity, total soluble solids and total sugar contents for tomato ‘KSU-TOM-107’ followed by ‘KSU-TOM-102’. However, this increase in nutritional value was accompanied with decrease in total yields by nearly 40-50%. KSU-TOM-102 irrigated at 75% ETc at fruiting stage or vegetative stage recorded 0 and 12% reduction of the total yield, respectively, while maintaining good nutritional value as compared with 100% ETc during all stages. Therefore, these treatments can be recommended as irrigation management strategy for tomato ‘KSU-TOM-102’ production under field conditions.