Characteristics of Actinidia deliciosa x A arguta and A arguta x A deliciosa hybrids

The aim of this study was to produce sweet kiwifruit with hairless skins by interspecific hybridization between A. deliciosa and A. arguta. From two F, populations of A. deliciosa x A. arguta and A. arguta x A. deliciosa, two genotypes DA1 and AD1, which had intermediate characters between maternal and paternal species, were selected and their morphological and horticultural characteristics were compared. Interspecific hybrid plants had intermediate characteristics in shoot diameter, internode length, and 1-year-old dormant shoot surface but the 4-5-year-old trunk showed paternal characteristics. Leaf shape was similar to that of A. arguta in both DA1 and AD1, although leaf size and hair density on leaf surface was intermediate between the two parental species. Budbreak, leaf expansion, and flowering of the two hybrids was earlier than in A. deliciosa, flowers were larger than those of A. arguta, and fruiting habits were similar to A. deliciosa. Fruit of DA1 and AD1 were twice the size of those of A. arguta but had smooth green skins. Fruit maturity was 10 days later than A. arguta but 1 month earlier than A. deliciosa. However, soluble solids content was lower than in both A. arguta and A. deliciosa. Cold tolerance was shown to be A. arguta > DA1 > AD1 > A. deliciosa. Flow cytometry indicated that the two hybrids were both hexaploid. Guard cell and stomatal size of the two hybrids were similar to those in A. arguta.