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Major breeding objectives. Fruit size has been an important criterion for selecting wild species from China with commercial potential (Ferguson and Huang, 2007). Kiwifruit could make an important contribution to human health (Singletary, 2012; Skinner et al., 2013); the fruits have outstanding nutritional qualities and are a good source of vitamin C, minerals, folic acid and fibre (Ferguson and Stanley, 2003). However, it can trigger allergic responses in some consumers (Lucas et al., 2003). Other important breeding objectives include time of maturity and ripening, handling and storage (Ferguson, 1990).

Diseases can affect the production of kiwifruit orchards. Reported kiwifruit diseases are mostly of fungal origin, i.e. Armillaria novae-zelandiae in New Zealand (Horner, 1992), Phomopsis sp. in Greece (Elena, 2009), Cadophora melinii in Italy (Prodi et al., 2008) and Verticillium albo-atrum in Chile (Auger et al., 2009). Blouin et al. (2012) identified two vitiviruses from A. chinensis in New Zealand. Bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa) is by far the most serious disease worldwide (McCann et al., 2013). Introduction of genotypes of Actinidia resistant to Psa is of critical importance.

BREEDING ACCOMPLISHMENTS. Breeding programmes have been initiated wherever the industry has been dependent on ‘Hayward’, e.g. New Zealand and Italy, to develop new cultivars that are better adapted. Selection was initially focused on openly pollinated seedlings in the wild or from named cultivars. The red-fleshed cultivar ‘Hongyang’ was selected from 3213 seedlings of A. chinensis var. rufopulpa (Wu and Li, 1993; Wang et al., 2003). ‘California Male’ and ‘Chico Male’ were selected from seedlings of A. chinensis var. deliciosa (Ferguson and Huang, 2007). Several A. chinensis var. deliciosa-derived cultivars have been obtained in New Zealand, i.e. ‘Abbott’, ‘Allison’, ‘Bruno’, ‘Gracie’, ‘Hayward’ and ‘Monty’ (Ferguson, 1997). Most cultivars have been derived from the original introduction of seeds into New Zealand (Ferguson and Huang, 2007).

Only a few selections have been derived from controlled crosses: ‘Tomua’ (New Zealand) is a cross of ‘Hayward’ with an early flowering male (Muggleston et al., 1998). ‘Summerkiwi™’ (Italy) was obtained from the cross of ‘Hayward’ with a fruiting male. Other A. chinensis var. deliciosa cultivars originating from controlled crosses include ‘Katiuscia’, ‘Silvia’ and ‘Stefania’ (Italy) and ‘Skelton’ (New Zealand), but none of these has been widely grown (Ferguson and Huang, 2007). With respect to A. chinensis var. chinensis, ‘Hort16A’ (New Zealand) is the most successful cultivar obtained from controlled crosses. It was selected from a cross between a male and a female derived from two seedling accessions from different parts of China (Muggleston et al., 1998; Ferguson et al., 1999).

Fairchild (1927) performed the first interspecific cross in Actinidia, crossing a female A. arguta with pollen of A. chinensis var. deliciosa. Since then, several other interspecific crosses have been made with reasonable success (Ferguson and Huang, 2007). Some interesting selections include ‘Kiri’, from a cross of A. arguta × A. deliciosa backcrossed to A. deliciosa (White and Beatson, 1993), ‘Kosui’, a hybrid of A. chinensis and A. rufa, ‘Shinzan’, from A. arguta × A. deliciosa, and ‘Sanryoku’, a hybrid of A. deliciosa and A. chinensis (Kokudo et al., 2003).

Although most of the cultivars obtained by breeding programmes have involved A. chinensis var. chinensis and A. chinensis var. deliciosa, other kiwi species have also been used, i.e. A. arguta, A. kolomikta and A. rufa (Ferguson and Huang, 2007).