Yield, quality and drought sensitivity of tomato to water deficit during different growth stages
Keywords:deficit irrigation, sensitivity index, irrigation management, high tunnel
In areas where the supply of water for irrigation is limited, tomato production is often subject to drought stress. In order to investigate the drought sensitivity of tomato (Lycopersicon esculentum Mill.) yield and quality during different growth stages, field and pot experiments were conducted in a high tunnel in southern China during the 2013 and 2016 growing seasons. The experiments consisted of four treatments. Crops were drip-irrigated to 100 % of field capacity at all growth stages divided into treatment T1 (control) and the treatment group T2, T3 and T4 receiving half the amount of irrigation as T1 when the soil water content reached 70 % of field capacity, the vegetative phase (stage I) T2, the flowering and fruit development phase (stage II) T3, and the fruit ripening phase (stage III) T4. Compared to the control treatment, drought stress at stages II and III caused a decrease in yield of 13 % and 26 %, respectively. Fruit firmness and color index were positively affected by drought stress, while fruit water content and shape index did not show any differences between treatments. Taste and nutritional quality parameters, such as total soluble solids, soluble sugar, organic acids and vitamin C improved in response to limited water supply (p ≤ 0.05). Despite having a negative effect on fruit yield, drought stress applied at stage III tended to enhance fruit quality traits. This study found that applying drought stress at stage I can be a positive management approach as it saves water and has fewer negative effects compared to applying drought stress at the other critical growth stages, thereby minimizing the adverse effects of drought stress.