DNA dodecaploid plants detected among somaclones of Actinidia deliciosa var. deliciosa cv. Hayward

Ninety two adventitious shoots (somaclones) were regenerated from leaf-derived callus of Actinidia deliciosa var. deliciosa cv. Hayward. Each somaclone was multiplied in vitro through axillary bud culture to produce several individual clonal shoots. A total of 671 shoots were exflasked but only 223 (33%) resulted in rooted plants. These represented 46 of the original 92 somaclones. Shoot apices from representative plants of each of the 46 somaclones were analysed by flow cytometry to detect changes in their DNA ploidy. Two somaclones had twice the DNA ploidy of hexaploid Hayward (6C) indicating that they were DNA dodecaploids (12C). Seven clonal derivatives of these two somaclones were also DNA dodecaploid. The mean length of their stomatal guard cells was significantly greater than those from hexaploid somaclones. This is the first description of a method to produce DNA dodecaploid kiwifruit plants.