3848:
Preharvest Factors Affecting Postharvest Peel Breakdown of Fresh Citrus
3848:
Preharvest Factors Affecting Postharvest Peel Breakdown of Fresh Citrus
Monday, August 2, 2010: 3:30 PM
Desert Salon 4-6
Preharvest Factors Affecting Postharvest Peel Breakdown of Fresh Citrus:
Author: Sambhav and Mark Ritenour
Univ. of FL, Indian River Research and Education Center, Ft. Pierce, FL 34945
Florida is the largest producer of citrus in the U.S.A., especially oranges for the juice market and grapefruit for the fresh market. Peel breakdown of fresh fruit usually manifests itself after packing and shipping and can result in major economic losses. Unusually severe peel breakdown problems were reported during the 2006-07 and 2007-08 fresh citrus seasons. Plots were established from 2007 to 2010 in commercial groves using standard fresh fruit growing practices to evaluate the effects of foliar nutritional sprays and water stress on peel breakdown of fresh citrus. Mono-potassium phosphate (MKP) was applied at 10.65 Kg MKP per acre (0-52-34; 3.62 Kg K2O per acre) with 1.81 Kg per acre low-biuret urea (46-0-0), magnesium (Mg) was applied at 6% (4.53 Kg Epsom salts / 75.70 gal), MKP + Mg was applied separately as two tank mixtures, or an antitranspirant (Vapor Gard®) was applied at concentrations of 1% and 2% as whole tree foliar sprays at a rate of 473.17 liters per acre. In addition, whole-tree water stress was induced by withholding water for up to two months before harvest. Fruit samples were harvested at weekly or biweekly intervals and held at ~ 22.7oC and 50-60% RH for three days before washing, waxing (carnauba) and then storing the fruit under ambient conditions. Evaluation of decay and the development of peel disorders and other physiological disorders occurred weekly or biweekly. Tree water stress was measured using a pressure bomb. Incidence of peel breakdown significantly increased after blocking irrigation and rainfall for 49 days before harvest. Foliar application of K, Mg, K + Mg, and Vapor Gard® reduced peel breakdown by about an average of 35.63%, 35.22%, 29.94%, and 45.03% respectively compared to control fruit. This trend continued the following season with less peel breakdown from the Vapor Gard® treatment whereas results from foliar K and Mg were not always significant.
Univ. of FL, Indian River Research and Education Center, Ft. Pierce, FL 34945
Florida is the largest producer of citrus in the U.S.A., especially oranges for the juice market and grapefruit for the fresh market. Peel breakdown of fresh fruit usually manifests itself after packing and shipping and can result in major economic losses. Unusually severe peel breakdown problems were reported during the 2006-07 and 2007-08 fresh citrus seasons. Plots were established from 2007 to 2010 in commercial groves using standard fresh fruit growing practices to evaluate the effects of foliar nutritional sprays and water stress on peel breakdown of fresh citrus. Mono-potassium phosphate (MKP) was applied at 10.65 Kg MKP per acre (0-52-34; 3.62 Kg K2O per acre) with 1.81 Kg per acre low-biuret urea (46-0-0), magnesium (Mg) was applied at 6% (4.53 Kg Epsom salts / 75.70 gal), MKP + Mg was applied separately as two tank mixtures, or an antitranspirant (Vapor Gard®) was applied at concentrations of 1% and 2% as whole tree foliar sprays at a rate of 473.17 liters per acre. In addition, whole-tree water stress was induced by withholding water for up to two months before harvest. Fruit samples were harvested at weekly or biweekly intervals and held at ~ 22.7oC and 50-60% RH for three days before washing, waxing (carnauba) and then storing the fruit under ambient conditions. Evaluation of decay and the development of peel disorders and other physiological disorders occurred weekly or biweekly. Tree water stress was measured using a pressure bomb. Incidence of peel breakdown significantly increased after blocking irrigation and rainfall for 49 days before harvest. Foliar application of K, Mg, K + Mg, and Vapor Gard® reduced peel breakdown by about an average of 35.63%, 35.22%, 29.94%, and 45.03% respectively compared to control fruit. This trend continued the following season with less peel breakdown from the Vapor Gard® treatment whereas results from foliar K and Mg were not always significant.