Kiwi

Actinidia deliciosa

1. Identification and origin

The kiwi [actinidia deliciosa (A. Chev.) C.F. Liang & A.R. Ferguson], belonging to the Actinidiaceae family, is a woody climber native to the humid forests of China. The crop was spread to New Zealand in the early 20th century, where it received the commercial name “kiwi”. It is currently cultivated in various temperate-climate regions, including Italy, Greece, Chile, Portugal and Spain.

2. Economic importance

The kiwi is one of the main temperate fruits exported worldwide. It stands out for its high content of vitamin C, fibre and antioxidant compounds. The main producers are China, Italy, New Zealand, Greece and Chile. In Portugal, production is concentrated mainly in the Entre-Douro-e-Minho and Beira Litoral regions, with growing economic relevance.

3. Botanical characterisation

A vigorous climber, dioecious (male and female plants separate), with woody stems and rambling growth. The leaves are large, ovate, pubescent. The female flowers are solitary or in small groups, while the male ones appear in inflorescences. The fruit is an oval berry, with a brownish, hairy skin, green or yellow flesh, rich in small seeds. The root system is shallow and sensitive to waterlogging.

4. Soil and climate requirements

It prefers humid temperate climates, with cold winters and moderate summers. It is sensitive to late frosts and strong winds. It requires deep, fertile, well-drained soils, with a pH between 5.5 and 7.0. The crop requires high water availability, especially during fruit growth. The installation of supports (pergolas or trellises) is indispensable.

5. Main pests

• Fruit fly (Ceratitis capitata): damage to ripe fruits.
• Scale insects (Coccoidea): sap sucking and honeydew production.
• Mites (Tetranychus spp.): chlorosis and reduced photosynthesis.
• Aphids (Aphis gossypii, Myzus persicae): leaf curling and virus transmission.
• Nematodes (Meloidogyne spp., Pratylenchus spp.): root galls and plant decline.

6. Main diseases

• Bacterial canker of kiwi (Pseudomonas syringae pv. actinidiae – PSA): the most serious disease of the crop, causing cankers, exudation and death of branches.
• Grey mould (Botrytis cinerea): rots in flowers and fruits.
• Armillaria (Armillaria mellea): root rot and death of plants.
• Phytophthora (Phytophthora spp.): root rots in waterlogged soils.
• Leaf spot (Alternaria spp., Cladosporium spp.): necrosis and premature leaf drop.

7. General crop management

It includes the choice of cultivars adapted to the local climate, installation of male and female plants in the appropriate proportion (normally 1:6 to 1:8), training on support structures, winter and summer pruning, regular watering without waterlogging, balanced fertilisation and monitoring of pests and diseases. The prevention of PSA is essential, including good hygiene practices, disinfection of tools and wound control.

Bibliographic references

• EPPO Global Database. Actinidia deliciosa – pests and diseases.
• CABI Invasive Species Compendium. Actinidia deliciosa – datasheets.
• Ferguson, A. R. (2016). Kiwifruit. In: Hancock, J. F. (Ed.), Temperate Fruit Crop Breeding. Springer.
• Testolin, R., et al. (2005). Kiwifruit breeding and genetics. In: Janick, J. (Ed.), Plant Breeding Reviews. Wiley.
• Huang, H. (2014). Biology and cultivation of kiwifruit. In: Advances in Plant Physiology. Scientific Publishers.