Tg. Thorp et al., SURVEY OF FRUIT MINERAL CONCENTRATIONS AND POSTHARVEST QUALITY OF NEW-ZEALAND-GROWN HASS AVOCADO (PERSEA-AMERICANA MILL.), New Zealand journal of crop and horticultural science, 25(3), 1997, pp. 251-260
New Zealand 'Hass' avocado (Persea americana Mill.) orchards were surv
eyed to determine if an imbalance in fruit mineral concentrations (Cal
cium (Ca), Magnesium (Mg), and Potassium (K)) was associated with poor
fruit quality. Ranges for average fruit mineral concentrations on sur
veyed orchards were: Ca, 25-47 mg/100 g dry weight (DW); Mg, 91-113 mg
/100 g DW; and K, 1126-1608 mg/100 g DW. Fruit with low Ca concentrati
ons had more vascular browning and flesh browning than fruit with high
Ca concentrations. Also, fruit Ca concentrations were lower and the i
ncidence of vascular browning higher in fruit that were more mature at
harvest. Fruit harvested below the minimum maturity standard (26% DW)
had practically no postharvest rots. If harvested above this standard
, 12-38% of ripe fruit had severe rots. A new disorder ''anthocyanin s
taining'' was observed in the flesh of several fruit. Results are disc
ussed in relation to industry options for predicting and managing frui
t quality.