Articles
KIWIFRUIT (ACTINIDIA)
Only one of these, the kiwifruit, A. deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson, is cultivated extensively and large quantities of fruit of another, A. chinensis Planch., are collected from the wild in China.
A few taxa are being cultivated experimentally; otherwise, most species have not been studied in any detail and their agronomic potential has not been tested.
Most taxa occur naturally only in China and few have been grown elsewhere in the world: even in China there is only a small number of representative living collections of Actinidia taxa.
Descriptions and comparisons of the taxa are therefore often based on studies of only a few, possibly atypical, plants.
It is not possible to describe in detail the attributes of all species and this chapter therefore concentrates on A. chinensis and A. deliciosa, the species of greatest potential.
The kiwifruit of commerce is one of the most recently domesticated of fruiting plants, having been introduced into cultivation only at the beginning of this century.
More striking, the whole kiwifruit industry, outside of China, depends on a single pistillate cultivar, ‘Hayward’. Most information that is readily available on kiwifruit or on the genus Actinidia refers to this cultivar.
There are few detailed or useful comparisons of fruit of the different kiwifruit cultivars probably because only ‘Hayward’ was planted during the rapid expansion of the kiwifruit industry.
Kiwifruit were first grown on a large scale in the Bay of Plenty, New Zealand and conditions there proved to be ideal for vine growth.
Cropping too was adequate once growers learned to adapt their techniques to suit the flowering behavior of ‘Hayward’. However, the success of the industry there has encouraged planting in areas that are less well suited to the particular requirements of ‘Hayward’. There is now a need for cultivars better adapted to these different environments and, perhaps, for conditions of the future if climatic patterns change.
As kiwifruit are dioecious, any new pistillate cultivar grown may require a corresponding change in accompanying pollenizer cultivars.
Reliance on a single cultivar is dangerous because of the risk of pests and diseases that can occur in a monoculture.
Furthermore, one of the main reasons for the appeal of the kiwifruit to consumers was its uniqueness.
As the kiwifruit has now progressed from being a specialty fruit to almost a commodity fruit there is a perceived marketing need for new or novel types of Actinidia fruits.
The kiwifruit vines grown in orchards are very similar to those found in the wild and there has been very limited selection by man.
Only a very small part of the gene pool has so far been exploited.
The genus Actinidia is variable, as are individual taxa,