บทคัดย่องานวิจัย

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On-orchard factors that influence the level of storage rots on Actinidia chinensis ‘Hort16a’ in New Zealand

Manning M.; Kay S.; Meier X. and Maguire K.

5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004, p.105

2004

บทคัดย่อ

On-orchard factors that influence the level of storage rots on Actinidia chinensis ‘Hort16a’ in New Zealand ZESPRI GOLD kiwifruit (Actinidia chinensis var chinensis ‘Hort16a’) can experience fungal rots in storage. The prevalence of these rots is influenced by the susceptibility of the fruit, the presence and amount of inoculum, and the harvest and storage regime. This abstract reports research o­n o­n-orchard factors that influence fruit susceptibility and the prevalence of the fungal pathogens. Fifteen orchards within the North Island of New Zealand were included in this trial.

Necrotic leaf discs and last seasons fruit peduncles were collected from each orchard and assessed for the presence of rot fungi. Information o­n shelter type, canopy structure and rating, orchard layout, irrigation, and contour in each orchard was also collected. Immediately after clearance to pick, 500 fruit were harvested from each orchard and placed into storage. The fruit were assessed regularly for rots and other storage disorders. Fruit with rots were removed and the causal pathogen(s) identified. The mean °Brix, flesh colour, firmness, dry matter, and mineral composition were also determined for each orchard. There were considerable differences in the incidence of the various fungi o­n the orchards sampled. The range of fungi was greater o­n leaf discs than o­n peduncles.

The incidence of post-harvest rots was low, with the majority of rots being associated with chilling injury. The main fungi associated with rots were Phomopsis spp. and Cryptosporiopsis actinideae. In some cases, the incidence of storage rots and the incidence of Phomopsis spp. o­n necrotic leaf discs were related. In general orchards with higher levels of rots had denser canopies. Further analysis also suggested linkages between a higher prevalence of rots and particular shelter species, warmer temperatures, higher rainfall and specific fruit nutrient levels. In addition more mature fruit tended to be less susceptible to rots associated with chilling injury.