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ACTINIDIA BREEDING PROGRAMME Breeding for new Kiwi varieties (Actinidia deliciosa,and chinensis var chinensis):
Fifteen years ago we started a kiwi-fruit breeding programme, using germplasm of Actinidia chinensis, chinensis. and deliciosa This germplasm derives from seeds of fruits which were collected in China, mostly in Guanxi Province. These fruits had different characteristics: the weight was from g 25 to g 100; the shape was heart-shaped, cylindrical, elliptic and flat; the skin colour was from brown-greenish to dark brown; the flesh colour was from green to yellow; the pubescence was poor or absent. From the seeds were obtained 54.6% of male seedlings and 45.4% of females. The blossoming time of the female seedlings is included between 25 and 17 days before that one of Hayward. The average duration of the cycle blossoming-ripening time is between 22 to 23 weeks, while the fruit picking time is included between 48 and 5 days before Hayward for the earliest seedling and the latest one respectively. The seedlings produced fruits with shape often different from that one of the fruit from which they derived. As regards the fruit size, the seedlings which derived from seeds of big fruits, generally produced bigger size fruits, while no seedling which derived from seeds of small fruits produced medium o large size fruit. Most seedlings produced fruits with poor pubescence, that generally disappears before ripening. Two third of the seedlings produced fruit with green-emerald flesh colour, while one third produced fruits with yellow flesh. The fruit taste was positively evaluated in 80% of the seedlings. The vitamin C content in fruit of the seedlings was normally higher than in fruits of Hayward and particularly one seedling had vitamin C three times higher than this variety. At the end of the first step of this breeding programme we obtained 2254 seedlings: 25% crossing (chinensis x deliciosa, deliciosa x chinensis), 75% open pollination; 60% male, 40% female. After several pomological and organoleptic evaluations, many advanced selections show distinctive and good characters. Research on source of genetic resistance to root-knot and lesion nematodes The reaction of genotypes of Actinidia arguta, A. chinensis and A. deliciosa to Italian populations of the root-knot nematodes Meloidogyne arenaria, M. hapla, M. incognita and M. javanica and the root-lesion nematode Pratylenchus vulnus was evaluated in a glasshouse. One genotype of A. arguta, seventeen of A. chinensis and fifteen of A. deliciosa were evaluated for their reaction to M. arenaria, M. hapla, M. incognita and M. javanica; and sixteen genotypes of A. chinensis were evaluated for their reaction also to P. vulnus. Five groups of about fifteen seedlings of each genotype were transplanted in trays filled with steam sterilised sandy soil and inoculated with 10,000 eggs of each root-knot nematode species or 5,000 specimens of P. vulnus per plant. Two, thirteen, one and five genotypes of A. deliciosa were resistant to M. arenaria, M. hapla, M. incognita and M. javanica, respectively. One genotype of A. deliciosa was resistant to M. hapla and another M. incognita. The remaining genotypes were susceptible to the root-knot nematode species tested. Twenty-one genotypes of A. chinensis were resistant to the root-lesion nematode P. vulnus.
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