Effects of Grafting and Green Manure Treatments on Postharvest Quality of Tomatoes

Abstract

Effects of green manures (Vicia faba) incorporated into the soil at different growth stages (FS (green manure mixed into the soil at flower stage) and SAH (green manure mixed into the soil at a stage after harvest)) on quality attributes of grafted and ungrafted tomatoes during cold storage were investigated. Fruit obtained from plants fertilized with different green manures were stored at 8 +/- 0.5 degrees C and 90 +/- 5% RH for 7, 14, and 21 days. At the end of each storage period, weight loss, respiration rate, firmness, soluble solids content, titratable acidity, vitamin C, and bioactive compounds of the fruit were determined. At the end of the storage periods, fruit of ungrafted plants had lower weight loss, respiration rate, and phenolic acids (except for caffeic acid), but greater firmness, soluble solids content (SSC), vitamin C, total phenolics (TPs), and antioxidant activity (AA). Green manure-treated fruit had greater weight loss, firmness, total flavonoids (TFs) (except for FS), and AA, but lower respiration rate, hue angle, SSC (except for SAH), acidity, vitamin C, and TPs (except for FS). Grafting x green manure interactions had significant effects on quality attributes of tomatoes. In ungrafted plants, as compared with the control, green manure yielded lower weight loss, hue angle, vitamin C, and TPs (except for FS), but greater respiration rate, firmness, SSC (except for FS), and AA. On the other hand, in grafted plants, again as compared with the control, green manure yielded greater weight loss, TPs (except for FS), TFs, and AA, but lower respiration rate, firmness, SSC, acidity (except for SAH), and vitamin C. At the end of storage, green manure-treated fruit had greater protocatechuic and 4-hydroxybenzoic acids than the control fruit. In terms of changes in fruit quality attributes during storage, the responses elicited by green manure treatments were dependent on whether or not plants were grafted. For instance, while green manure treatments increased weight loss of the fruit from grafted plants, they decreased weight loss of fruit from ungrafted plants at the end of 21-day storage.