Summary

Postharvest physiological disorders could arise from certain metabolic faults or pre-harvest and environmental factors. Disorders differ from diseases in which another organism is associated with. Considerable losses of harvested fruits may result from disorders. Pulp disorders may prevent fruits from consumption or marketing locally or overseas. Disorders often create doubts also in the mind of suppliers and consumer regarding the quality of produce to be marketed. The research will investigate three major postharvest disorders relevant to Sri Lanka, (i) fruit pitting, in guava and mango var. `Karuthacolomban”, (ii) “husk scalding”, (iii) “pulp spot” and (iv) Vascular browning of avocado. Current understanding of these disorders is inadequate for devising management strategies.The project outcome is expected to help overcome the disorders and reduce the postharvest fruit loss that the disorders bring about, thereby increasing fruit availability for human consumption and exportation of good quality fruit. The outcome would also include a trained postgraduate and journal publications

Objectives

(i) understand the histology of the process of pitting development, husk scald, pulp spot and vascular browning in avocado, and determine the exact stage of appearance of visible pitting symptoms in different fruit species

(ii) investigate micro- and or macro-elements as a possible cause/s of initiation and development of pitting disorder, by extensive tissue analyses, using ICP and EDX and associated events,

(iii) to examine if any organism/s is consistently associated with pitting, husk scalding, pulp spot or vascular browning, by repeated isolation on media followed by molecular identification,

(iv) study the possibility of degradation of cell walls, below the epidermis of fruit peel, by host pectinases as a mechanism of pitting development indirectly by analysis of the enzyme product, galacturonic residues,

(v) develop strategies for management of pitting disorder in three fruit species, using every information gathered above.

(vi) study the cause and factors affecting the development of husk scalding, pulp spot and vascular browning disorders in harvested avocados, and

(vii) to devise appropriate management strategies, using above information, for each disorder.

Major Equipment Facilitated by Grant