Breeding a New Stony Hard Peach Cultivar to Become Soft, ‘Kaitouka17’

Kaitouka17’ was bred with the target of cultivating a variety to replace the early-ripening variety ‘Hikawahakuho’ in Yamanashi Prefecture. The beginning of harvest for ‘Kaitouka17’ is almost identical to that of ‘Hikawahakuho’. The fruit weight is 298 g, which is high for an early-ripening variety. The flesh was a weak tendency to split. The skin color pattern is solid flush, and it readily colors uniformly. The flesh firmness was 2.4 kg on the first day of harvest and decreased with the passage of days. In 2016, it was 2.0 kg after 16 days of first harvesting, and in 2017, it was 1.9 kg after 18 days of first harvesting. The flesh firmness of the auxin-treated fruits after harvest was 0.4 kg 9 days after treatment, and the amount of ethylene produced increased rapidly 1 day after treatment. However, DNA markers revealed that ‘Kaitouka17’ was a stony hard peach. Thus, this study showed that ‘Kaitouka17’ had moderately soft flesh in spite of having the stony hard flesh allele. ‘Kaitouka17’ is expected to be widely used as a substitute for ‘Hikawahakuho’ and later-ripening varieties.