Chemical Control of Fruit Ripening In Guava

No Thumbnail Available
Date
2007
Authors
Ibtissam Abdalla Mohamed Nour
Journal Title
Journal ISSN
Volume Title
Publisher
University of Khartoum
Abstract
White- and pink-fleshed guava fruit types grown in Sudan were selected for this study. Mature-green fruits of the two guava types were obtained from an orchard at Al-Kadaro, Khartoum North (Lat. 15O 40' N, Long. 32O 22' E). Fruits were selected for uniformity of size, colour and freedom from blemishes. The fruits were washed, dried and transported in plastic baskets to the experimental laboratory. Three experiments were carried out in this study: 1. Experiment One: The effect of ethrel in aqueous solutions at 250, 500 and 1000 ppm and ethylene released from ethrel at 250, 500 and 1000 ppm was evaluated on fruit ripening of the guava types at 20 + 1OC and 85-90% r.h. ripening was enhanced in all treated fruits of both guava types at all concentrations used. The ripening rate progressively increased with the increase in concentration. Ethylene released from ethrel was more effective in triggering fruit ripening that dipping fruits in aqueous solution of ethrel. Depending on concentration, ripening was 2-6 days faster in fruits dipped in aqueous solutions of ethrel and 6-9 days earlier in fruits treated with ethylene released from ethrel, compared with untreated fruits. The effect on fruit ripening was indicated by enhanced climacteric peak of respiration increased peel colour, increased total soluble solids and decreased flesh firmness. 2. Experiment Two: The effect of postharvest treatment by maleic hydrazide (MH) and waxing on ripening and quality of white and pink guava fruits was evaluated at 20 + 1OC and 85-90% r.h. MH at 250, 500 and 1000 ppm delayed fruit ripening by 2-6 days in both guava types compared to untreated fruits. The higher the concentration, the more the delay in fruit ripening. Waxing in addition to MH treatment resulted in 3-4 days more delay in fruit ripening, compared to MH treatment alone. The effect of MH treated and waxing in delaying fruit ripening was manifested in retarded climacteric peak of respiration, delayed peel colour development, reduced total soluble solids accumulation and decreased fruit softening. 3. Experiment Three: The effect of postharvest treatment by gibberellic acid (GA3) and waxing on ripening amd quality of white and pink guava fruits was evaluated at 20 + 1OC and 85-90% r.h. GA3 at 100 and 200 ppm without waxing delayed fruit ripening by 3-5 days in both guava types, compared to untreated fruits. The delay was more with the increase in GA3 concentration. Waxing in addition to GA3 treatment resulted in 3 days more delay in fruit ripening, compared to GA3 treatment alone. The effect of GA3 and wax treatments was indicated by retarded climacteric peak of respiration, delayed peel colour development, reduced total soluble solids accumulation and decreased flesh softening.
Description
A Thesis submitted to the University of Khartoum in Partial Fulfillment of the Requirements for the Degree of Master of Science in Agriculture
Keywords
Horticulture Chemical Control Fruit Ripening Guava University of Khartoum
Citation
Ibtissam Abdalla Mohamed Nour, Chemical Control of Fruit Ripening In Guava .- Khartoum : University of Khartoum, 2007 .- 110p. : illus., 28cm., M.Sc