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EFFECT OF CALCIUM ON POST-HARVEST DECAY OF TELFAIRIA OCCIDENTALIS

NB ONYIKE and SID EZOII

Department of Botany, School of Biological Sciences, Abia State University, Uturu, Abia State, Nigeria

Background and objectives
Telfairia occidentalis Hooker is an important staple vegetable grown in rural farms in eastern Nigeria from where it is transported to the cities. The plant produces luxuriant edible green leaves which are rich in vitamins and iron. The post-harvest life of this vegetable is only 3 days at room temperature, after which it turns yellow or decays especially under humid environment. Cold-temperature storage is expensive and unreliable because of power interruptions in Nigeria and may result in cold injury and loss of flavour. Since calcium has been reported to increase resistance of plant tissues to soft rot diseases [1, 2], the objective of the study was to investigate the effect of calcium on post-harvest decay of T. occidentalis.

Materials and methods
Leaves of T. occidentalis were randomly collected from vegetable stands grown with organic manure in the experimental plots of Abia State University, Uturu. The leaves were thoroughly mixed and divided into six groups. Each group was washed with a solution of different calcium chloride concentration and dried. 500 g of leaves were put in perforated polyethylene bags, then incubated for 12 days in a moist chamber in the dark. At 3-day intervals, samples of leaves from different treatments were examined for decay. The area of rotted tissue was measured, and the microorganisms associated with the rotting isolated and identified. The data were analysed by analysis of variance followed by Fisher's least significant difference test (a=0.05).

Results and conclusions
Soft rot of T. occidentalis leaves was reduced in calcium-treated leaves. The highest reduction was observed at 0.01 M calcium chloride concentration. Species of Erwinia and Alternaria were the pathogens most frequently isolated from the rotted tissues. The results suggest that calcium could be used to control post-harvest decay of T. occidentalis.

References
1. Platero M, Tejerina G, 1976. Phytopathology 85, 314-319.
2. Kelman A, McGuire RG, Tzeng K-C, 1989. In AE Engelhard, ed., Soil Borne Plant Pathogens - Management of Diseases with Macro- and Microelements, pp. 102-121.