Preharvest Foliar Spray of Calcium Chloride on Growth, Yield, Quality, and Shelf Life Extension of Different Lowland Tomato Varieties in Malaysia

Effects of Ca Sprays on Fruit Ca Content and Yield of Tomato Variety Susceptible to Blossom-End Rot

Several factors are involved in the incidence of blossom-end rot (BER) in tomato fruit, but the main one is insufficient Ca uptake and transport through the plant, resulting in Ca deficiency in the fruit. Sprays of Ca-containing products are considered to be a possible measure to overcome the local Ca deficiency in tomato fruit. Therefore, the main objective was to evaluate the effectiveness of additional Ca supply to tomato fruits for increasing Ca content and reducing fruit damage. Sprays of five different commercial preparations containing (Brexil Duo, Calmax Zero N, Ca(NO₃)₂, CaCl₂) or promoting (Greenstim) Ca uptake were tested using BER-sensitive large-fruit variety 'Beorange'. The experiment was conducted in the commercial greenhouse 'Getlini EKO', Latvia, during the autumn-spring season of 2020/2021 under controlled conditions, eliminating the adverse impact of external factors. The results revealed that none of the preparations were effective in increasing Ca content, preventing BER, and did not promote the tomato yield. As good agricultural practices were followed in the greenhouse to manage BER, we concluded that a non-marketable yield of around 15% should be expected for 'Beorange' when grown under artificial light, possibly due to the impact of abiotic stresses and genetically determined susceptibility.

Effects of preharvest applications of chemicals and storage conditions on the physico-chemical characteristics and shelf life of tomato (Solanum lycopersicum L.) fruit

The aim of this study was to investigate the influence of preharvest sprays of chemicals and evaporative cooling (ZECC) on the postharvest physico-chemical quality and shelf life of tomatoes. The experiment was conducted using a combination of ten preharvest sprays of chemicals (chitosan (0.1%), chitosan (0.3%), chitosan (0.5%), salicylic acid (SA) (0.015%), SA (0.03%), SA (0.045%), calcium chloride (CaCl₂) (1%), CaCl₂ (3%), CaCl₂ (5%) and control) and two storage conditions (ambient environment storage and ZECC). The design of the experiment was completely randomized design with three replications. Data were collected from tomato samples (Solanum lycopersicum L. cv. ARP tomato D2) on four days interval. The result showed that all physico-chemical quality indicators were significantly (p ≤ 0.05) affected by both preharvest sprays and storage conditions. CaCl₂ (5%) sprays extended the shelf life of tomato by 6 days in ZECC and 11 days in ambient storage compared to the control. The highest concentration of CaCl₂ and SA sprays minimized PLW and maintained fruit marketability compared to the control. The firmness of tomatoes was better retained with the sprays of SA (0.045%) in both storage conditions. CaCl₂ (5%), SA (0.045%) and chitosan (0.5%) sprays retained the titratable acidity by 42.86%, 47.62% and 33.33%, respectively compared to the control inside ZECC storage. At the end of storage period, the highest TSS was observed on tomatoes sprayed with SA (0.03%) followed by chitosan (0.1%) and chitosan (0.3%). The lycopene contents were lower with sprays of SA (0.045%), SA (0.03%), CaCl₂ (3%), CaCl₂ (5%) and chitosan (0.1%) stored inside ZECC indicating the effectiveness of preharvest sprays in delaying lycopene accumulation. Moreover, the AA contents of tomatoes sprayed with CaCl₂ (5%), SA (0.045%) and chitosan (0.1%) were higher by 34.10%, 38.19% and 23.84%, respectively compared to the control. The result indicated that combining preharvest chemical sprays and ZECC storage is important to maintain the physico-chemical quality and shelf life of tomatoes.

Foliar application of salicylic acid and calcium chloride delays the loss of chlorophyll and preserves the quality of broccoli during storage

Consumer awareness of broccoli's unusual color, rich flavor, and concentration of desired phytochemicals has led to a steady increase in consumption in recent years. However, its short shelf-life, which is linked with quick discoloration and degeneration after harvest, limits industrial production and marketing. The effect of pre-harvest salicylic acid (SA) and calcium chloride (Ca) and their combination on the post-harvest quality of broccoli during storage (5 ± 1°C) was explored in this study. The foliar spray treatments reduced weight loss of broccoli head during storage. At the end of storage, Ca (2%) alone and in combination with SA (0.01%) significantly maintained the chlorophyll concentration rather than control. The total phenols, flavonoid, and antioxidant capacity of the Ca (2%) + SA (0.01%) treated samples was significantly greater than the control. SA (0.01%) alone or in conjunction with Ca (2%), showed higher catalase (CAT) activity; however, Ca (1%), alone or in combination with SA (0.01%), showed higher peroxidase (POD) activity. Generally, the marketability of the treated broccoli was significantly greater than the control at the end of storage. Based on these findings, we believe Ca (2%) + SA (0.01%) improves the antioxidant system, delays chlorophyll degradation, and extends the shelf life of broccoli heads stored at 5 ± 1°C. It is proposed that the green color, marketability, and nutrient content of broccoli during postharvest handling and storage can be retained longer by foliar application of this treatment. PRACTICAL APPLICATIONS: Broccoli (Brassica oleracea L. Italaia) is a widely-consumed floral green vegetable due to its high content of nutrients and bioactive compounds. However, after harvest, florets rapidly senesce and suffer from yellowing which affects the quality of broccoli. The senescence of post-harvest broccoli is characterized by fresh weight loss, chlorophyll degradation, and a significant reduction in nutritional content. Therefore, preventing the decline in the quality of harvested broccoli is essential to maintain its economic and nutritional value. The results of this study showed that pre-harvest foliar application of Ca (2%) + SA (0.01%) with delayed weight loss, chlorophyll degradation, preservation of antioxidant compounds, and increased enzyme activity has a positive effect in maintaining broccoli heads quality during cold storage.