Yield, quality and drought sensitivity of tomato to water deficit during different growth stages

ABSTRACT 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.

摘要 在灌溉用水受限的区域，番茄生产常遭受干旱胁迫。为探究番茄（Lycopersicon esculentum Mill.）在不同生育阶段的产量与品质对干旱胁迫的敏感性，本研究于2013年与2016年生长季，在中国南方的高棚设施内开展了田间与盆栽试验。试验共设置4个处理组：所有生育阶段均采用滴灌至田间持水量100%的处理为T1（对照组）；T2、T3、T4为处理组，当土壤含水量达到田间持水量70%时，其灌水量为T1的一半，其中T2仅在营养生长期（阶段I）实施干旱胁迫，T3在开花与果实发育阶段（阶段II）实施，T4在果实成熟阶段（阶段III）实施。相较于对照组，阶段II与阶段III的干旱胁迫分别使产量下降13%与26%。果实硬度与色泽指数因干旱胁迫得到正向改善，而果实含水量及果形指数在各处理组间无显著差异。味觉与营养品质相关参数，如总可溶性固形物、可溶性糖、有机酸及维生素C，在有限供水条件下均得到显著提升（p ≤ 0.05）。尽管阶段III的干旱胁迫对果实产量存在负面影响，但该处理往往能提升果实品质性状。本研究发现，在阶段I实施干旱胁迫是一种积极的栽培管理手段：相较于其他关键生育阶段的干旱胁迫处理，其节水效果显著且负面影响更小，可最大程度降低干旱胁迫带来的不利影响。