ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Within Vine Distribution of Physiological Pitting in ‘Hayward’ Kiwifruit

Thorp, G, Ferguson, I, Barnett, A, and Boyd, L

1 The Horticulture and Food Research Institute of New Zealand Ltd., Mt Albert Research Centre, PB 92 169, Auckland, New Zealand. 2 The Horticulture and Food Research Institute of New Zealand Ltd., Te Puke Research Centre, R.D. 2, Te Puke, New Zealand.

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บทคัดย่อ

Physiological pitting is a disorder that appears in ‘Hayward’ kiwifruit after long term storage. The symptoms are small, darkened indentations or pits on the skin and are distinct from those occurring from sunburn or from pitting associated with fungal pathogens. We examined the possible link between this disorder and fruit mineral concentrations. Over two seasons, fruit from 35 orchards were sampled from the distal and proximal ends of fruiting canes and from shoots with high and low leaf:fruit ratios. We found that fruit from short shoots with fewer leaves produced fruit with lower calcium and magnesium and higher phosphorus concentrations, and with higher incidence of physiological pitting after storage, than fruit from long shoots with high leaf areas. It was also found that fruit on shoots at the distal ends of fruiting canes

tended to have lower calcium and magnesium, higher phosphorus and more pitting, than fruit on shoots at the proximal ends of canes. These relationships do not necessarily imply that pitting is caused by calcium or magnesium deficiency, nor by high phosphorus levels in the fruit. Rather we believe that conditions that result in these nutrient levels being low in the fruit may also make the fruit susceptible to pitting. For example, any perturbation to water flow in the vine may affect calcium and magnesium supply to the fruit. The positional effects also have implications for fruit sampling and need to be taken into account when developing strategies for determining fruit mineral concentrations to predict pitting incidence in stored fruit.