The effect of pre and postharvest of calcium applications on antracnoses (Colletotrichum gloeosporioides) severity, and quality of papaya (Carica papaya) fruit.
Saborio, D., Saenz, V., Arauz, L. F., and Bertsch, F.
Agronomia Costarricense, Volume 24, Number 2, 2000. pp. 77-88
2000
บทคัดย่อ
The effects of pre and postharvest of calcium applications on anthracnose (Colletotrichum gloeosporioides [Glomerella cingulata]) severity and quality of pawpaw (Carica papaya) fruit were evaluated in 2 separate experiments. Preharvest treatments comprised: CaCl2 spraying at 1 or 4% in 2 applications (40 days after anthesis (dpa) and between 100 and 140 dpa); CaCO3 soil application (1 t/ha, 70 dpa) and the control (0% Ca). Postharvest treatments comprised: 5 minute-immersion in water with 0% calcium, 1 and 4% of CaCl2, all with a penetrating agent. Severity, percent calcium content of peel, brix, pH, % titratable acidity, firmness (peel and pulp) and percent ripeness were evaluated. For the preharvest Ca application, the severity was: 6% for the 1% CaCl2 treatment, 7% for the control, 9% for the solid CaCO3 treatment and 11% for the 4% CaCl2 treatment. Ca had no effect in diminishing the disease severity. The highest values of shell and pulp firmness were obtained upon treatment with 1% CaCl2 (31.97 and 19.63 N, respectively). For acidity and pH, 4% CaCl2 treatment accelerated fruit ripening since the acidity diminished and the pH increased compared with 1% CaCl2. The postharvest Ca applications reduced the disease severity from 23% for the control treatment to 12 and 11%, for the 1 and 4% CaCl2 treatments, respectively. As the rates increased, the Ca concentration in the peel of the fruits increased. As for pH, the 4% CaCl2 treatment recorded a lower value compared to other treatments and brix was lower than the observed for the 1% CaCl2 treatment. It is possible that increasing the rates from 1 to 4% may have had an effect in delaying the fruit ripening.