Effect of Using Rootstock Low-chilling ‘Okinawa’ on ‘Hikawahakuhou’ Peach Flowering

Abstract

Global warming is making it difficult to achieve the chilling requirement for the completion of endodormancy in protected peach cultivation. To stabilize peach production in the face of warming winters, we examined the use of rootstock low-chilling ‘Okinawa’ and endodormancy-breaking treatments. In pot culture, ‘Hikawahakuhou’ on ‘Okinawa’ rooted and flowered earlier than ‘Hikawahakuhou’ on ‘Ohatsumomo’. Therefore, it was suggested that rootstock low-chilling ‘Okinawa’ influences the flowering of ‘Hikawahakuhou’. In field culture, ‘Hikawahakuhou’ on ‘Okinawa’ led to commercial fruit quality and growth. In the field with ‘Hikawahakuhou’ on ‘Okinawa’, the application of either of two endodormancy-breaking treatments, hydrogen cyanamide sprayed after 400 to 600 chilling hours or nitrogen metabolism solution sprayed after 600 to 800 chilling hours, advanced both flowering and harvesting dates. Under continued global warming, the use of ‘Okinawa’ as a rootstock and endodormancy-breaking treatments will enable continued production of peach.