ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Responses to ethylene of citrus stem-end rot and its causal agent, Diplodia natalensis.

Brown, G. E.

Proceedings of the Florida State Horticultural Society Year: 1994, recd. 1995 Issue: No. 107 Pages: 298-301 Ref: 17 ref.

1995

บทคัดย่อ

ABSTRACT :

Stem-end rot, a major postharvest decay of Florida citrus fruit caused by the fungus Diplodia natalensis [Botryodiplodia theobromae], is significantly enhanced by ethylene used during the commercial degreening process. Concentrations of ethylene above the 5-10 ppm required for optimum degreening will even stimulate greater incidence of decay. In studies conducted to elucidate the role of ethylene in this disease, atmospheres containing high ethylene (55 ppm) significantly enhanced in vitro growth of D. natalensis over that observed in air or 2 ppm ethylene. Quiescent propagules of the fungus at the fruit stem-end were distributed on surfaces of the calyx and disk (button) and adjoining fruit base. The fungus was recovered less frequently from the fruit base than from the button of Hamlin oranges, but equally frequent from these two areas when using Valencia fruit. The fungus was rarely isolated from tissue of the abscission zone after 3 days of ethylene treatment. Viability of D. natalensis, as

measured by its frequency of recovery, was not influenced by high ethylene levels. Removal of the button from fruit during high ethylene degreening significantly reduced disease, but total levels and the pattern of disease development were significantly altered by time of button removal during the degreening process. These studies provided additional information pertaining to the role of ethylene in stem-end rot development, but further investigations are still needed to more thoroughly explain the action of ethylene.