2022 Volume 15 Issue 2 Pages 95-100
Avocado cultivation is expected to expand in Japan because of steadily increasing consumption there. However, there are several problems to resolve before its promotion. In particular, low temperatures in winter seem to be the most critical issue. Therefore, we evaluated the cold tolerance of avocado by means of several methods. Seven avocado cultivars were used as material in the analyses of chlorophyll fluorescence and electrolyte leakage of leaves and the FDA staining of the cross-section of stems. The damage index of the leaves was measured using these seven and 12 additional cultivars. As a result, there was no significant difference at -3°C in the Fv/Fm value of chlorophyll fluorescence in any of the cultivars. The Fv/Fm value of ‘Ferute’ at -6°C was significantly higher than that of ‘Bacon’. The Fv/Fm value of ‘Mexicola’ at -9°C was significantly higher than that of the other cultivars. Regarding the damage index of the leaves, ‘Mexicola’, ‘Fuerte’, ‘Winter Mexican’, and ‘Ettinger’ looked healthy, although there were 15 cultivars, which showed low-temperature damage at -6°C. There was no significant difference in electrolyte leakage in any of the cultivars. On the evaluation of the FDA staining of the cross-section of stems, ‘Hass’ was damaged at -5°C, whereas ‘Mexicola’ tolerated temperatures as low as -8°C. These results were similar to those of previous studies. Therefore, all the except for electrolyte leakage, used in this study, were considered to be useful for, evaluation of cold tolerance in avocado.
