Characteristics of vegetative growth and fruit of progenies obtained from crosses between octoploid persimmon ‘Hasshu’ and hexaploid persimmons

‘Hasshu’ is a dwarf, octoploid (2n=120=8x) bud-sport persimmon (Diospyros kaki) cultivar selected from the nonaploid (2n=135=9x) ‘Hiratanenashi’ in Japan in 2005. Unlike seedless ‘Hiratanenashi’, ‘Hasshu’ bears only female flowers and produces fruits with germinable seeds. Most persimmons are hexaploid (2n=90=6x), and some cultivars bear male flowers. Septaploid (2n=105=7x) persimmons could be created from crosses between octoploid and hexaploid persimmons but have not been found in nature. To create septaploids, we pollinated ‘Hasshu’ flowers with pollen from hexaploid ‘Zenjimaru’ and ‘Taishu’. As the cells at the root tips of both ‘Hasshu’ × ‘Zenjimaru’ and ‘Hasshu’ × ‘Taishu’ seedlings had 105 chromosomes, these hybrids were septaploid. The seedlings were clearly shorter than the hexaploid × hexaploid seedlings, and the leaves were small. Five of six hybrid lines grown in the field produced fruits with germinable seeds. These results indicate that the progeny of ‘Hasshu’ are dwarfed, and the dwarf trait is dominantly inherited and that septaploid persimmons can form normal germinable seeds.