Managing Fruit Soluble Solids with Late-season Deficit Irrigation in Drip-irrigated Processing Tomato Production

Abstract

<jats:p>Fruit soluble solids concentration (SSC) is an important quality factor for tomatoes (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.) grown for processing. The use of drip irrigation often results in undesirably low SSC. The effects of late-season irrigation management on fruit yield and SSC was investigated in a series of drip-irrigated field trials in California from 2000–04. The effects of irrigation cutoff or deficit irrigation implemented 40 to 50 days preharvest (the period corresponding to the initiation of fruit ripening) were compared to a standard grower practice of irrigation cutoff 20 days preharvest. Irrigation cutoff 40 to 50 days preharvest increased SSC but resulted in substantial yield loss, with significantly reduced brix yield (Mg fruit solids ha<jats:sup>-1</jats:sup>). By contrast, deficit irrigation significantly increased SSC compared to the standard practice, with no significant loss of brix yield. In three commercial fields the effect of deficit irrigation on fruit SSC was investigated. Fruits were sampled on three dates: 1) 4 to 5 weeks preharvest, early-ripening, pink-stage fruit only, 2) about 1 week preharvest, both late-ripening, pink-stage fruit and early-ripening fruit now fully ripe, and 3) commercial harvest, composite of early- and late-maturing fruit. SSC increased in response to soil moisture stress induced by deficit irrigation, with late-maturing fruit as much as 1.6 °brix higher than fruit maturing before significant soil moisture stress. However, once a fruit reached the pink stage of maturity, its SSC was not affected by subsequent soil moisture stress. An additional five commercial field trials were conducted to compare growers' irrigation practices with greater degrees of deficit irrigation. In each field the grower's deficit irrigation regime was compared to a reduced treatment receiving 25% to 50% less water over the final 4 to 7 weeks before harvest. Across fields, applying 20% to 60% of reference evapotranspiration (ET<jats:sub>o</jats:sub>) over the fruit ripening period resulted in acceptable SSC without significant brix yield reduction. We conclude that deficit irrigation initiated during early fruit ripening provides a flexible tool for SSC management. Brix monitoring of earliest ripening fruit can help classify fields as to the severity of irrigation deficit required to reach desirable SSC at harvest.</jats:p>

Yield, physicochemical traits, antioxidant pattern, polyphenol oxidase activity and total visual quality of field‐grown processing tomato cv. Brigade as affected by water stress in Mediterranean climate

“…This fact may also have important implications for industrial purposes (for paste or concentrated juice), since tomatoes higher in TSS content may require less energy to evaporate water from the fruit . Moreover, it is well known that a high TSS content of tomatoes improves their processing efficiency . No favourable effect of water stress on pH, which is an important characteristic in terms of processing requirements, was observed.…”

“…12 Moreover, it is well known that a high TSS content of tomatoes improves their processing efficiency. 31 No favourable effect of water stress on pH, which is an important characteristic in terms of processing requirements, was observed. Values of pH in both water regimes did not exceed the minimum (≤4.30) allowed to define the product as 'good' according to the reference scale of analytical parameters for processing tomato pulp.…”

Assessing the response of yield and comprehensive fruit quality of tomato grown in greenhouse to deficit irrigation and nitrogen application strategies

“…The major osmotic compounds accumulated in fleshy fruits are soluble sugars and acids (primarily malic and citric acids), which determine taste and represent more than half of the total dry matter in tomato (Ripoll et al, 2014). It has been proved that deficit irrigation at early fruit ripening stage could effectively increase TSS contents in processing tomato (Johnstone et al, 2005). Deficit irrigation applied near fruit ripening stage possesses the greatest positive influence on glucose and fructose accumulation in tomato fruits (Ripoll et al, 2014).…”

Re‐evaluation of traditional Mediterranean foods. The local landraces of ‘Cipolla di Giarratana’ (Allium cepa L.) and long‐storage tomato(Lycopersicon esculentum L.): quality traits and polyphenol content

“…The high TS and SS contents make long‐storage tomato suitable for use in the processing of both pastes and concentrates. In particular, a high SS level has been demonstrated to improve the processing efficiency . The high SS level also compensates for the low yield levels of long‐storage tomato, resulting in satisfactory Brix yields (≥1.5 t ha −1 ), lower than those obtained with processing tomato cultivated in similar semi‐arid environments under full irrigation (∼2.5 t ha −1 ) but higher than those obtained in these environments under deficit irrigation (∼1.3 t ha −1 ) .…”