2.5. Fruit quality at matured green stage and weight loss in storage
Two matured green fruit per plant were harvested on 139 DAS coinciding with the commercial harvest for fresh consumption. The fruit were weighed, assessed for total soluble solids concentration (TSSC), skin colour, internal ethylene concentration, and CO2 production (respiration) as outlined below. Fruit were oven-dried at 711 8C to a constant mass and the dry mass recorded. Gas was collected in test tubes from the fruit cavity using 50 ml syringes (Hamilton, Co., Nevada) while submerging the fruit under water. Gas samples (1 ml) were withdrawn from the test tubes using 1 ml gas-tight syringes and injected into a gas chromatograph (Pye Unicam, GCD) fitted with a flame ionization detector with H2 and airflow rates of 30 and 300 mlper minute, respectively. Theresponseto sample injectionwas determinedfrompeak height using a Hewlett Packard integrator (Model 3390 A) calibrated with external ethylene standards (B.O.C. gases,New Zealand Ltd.). Another 1 mlsampleofgas was withdrawnand injected into a GC-8A Shimadzu gas liquid chromatogram for determination of CO2 concentration. Fruit skin colour was measured using a chromameter (CR-200; Minolta, Osaka, Japan) on two opposite sides of the equatorial region of fruit. TSSC was determined onjuiceextractedfromasliceofpericarpfromtheequatorialregionofthefruitusingahandheld refractometer (ATC-1 Atago, Tokyo, Japan) with automatic temperature compensation. To assessthe effectof treatments on storage life, two matured green fruit fromeach plant (30 fruit/treatment)were harvested onthe sameoccasion (139 DAS) and werestoredina storage room maintained at 25 8C with relative humidity of 65%. Weight loss measurements were made every 2 days for a 12-day period by weighing individual fruit. Fruit weight loss was calculated as a percentage reduction from the initial fresh weight.