Effect of deficit irrigation on total yield, fruit physical characteristics and nutritional value in four drought tolerant tomato (Solanum lycopersicum L.) genotypes

Water deficit is a major factor limiting plant productivity of 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-۱۰۲, KSU-TOM-۱۰۶, KSU-TOM-۱۰۷ and TL–۰۱۸۶۰) were evaluated in response to deficit irrigation (DI) under field conditions. Three levels of crop evapo-transpiration (ETc; ۵۰%, ۷۵% and ۱۰۰%) were applied at three different growth stages (vegetative, flowering and fruiting stage) to the four tomato genotypes. Tomato genotypes differed in their responses to water deficit. Among different genotypes, KSU-TOM-۱۰۲ recorded the highest average total yield (۸۹.۵۴ t.ha-۱) under irrigation treatment with ۱۰۰% of ETc during all stages as well as ۷۵% of ETc during the fruiting stage. But, in general, total yield decreased under water deficit. Significant (P≤۰.۰۵) differences in fruits quality characteristics exerted by irrigation water treatments, tomato genotypes and their interactions. Irrigation with water at ۵۰% ETc at all growth stages significantly (P≤۰.۰۵)  increased vitamin C, titratable acidity, total soluble solids and total sugar contents for tomato ‘KSU-TOM-۱۰۷’ followed by ‘KSU-TOM-۱۰۲’. But, this increase in nutritional value was accompanied with decrease in total yields by nearly ۴۰-۵۰%.   KSU-TOM-۱۰۲ irrigated with water at ۷۵% ETc at fruiting stage or vegetative stage recorded ۰% and ۱۲% reduction of the total yield, respectively, while maintaining good nutritional value as compared with ۱۰۰% of ETc during all stages. Therefore, these treatments can be recommended as irrigation management strategy for tomato ‘KSU-TOM-۱۰۲’ production under field conditions.

Keywords:

fruit quality , nutritional value , water stress , water saving