Preliminary results of frost hardiness of Hungarian bred Persian walnut cultivars

Knowledge of ecological demands of all fruit crops and cultivars is essential to find its optimal growing site. In the case of cultivars adapted to the Hungarian climate conditions late spring frosts can cause serious damages and can decrease the effectiveness of fruit growing. To determine the frost hardiness of Hungarian bred Persian walnut cultivars experiments were made between October 2014 and March 2015. During this research period, a frost hardiness trial was established using a climate chamber. Three Hungarian basic cultivars (‘Milotai 10’, ‘Alsószentiváni 117’, ‘Tiszacsécsi 83’), four Hungarian novel bred cultivars (‘Milotai bőtermő’, ‘Milotai intenzív’, ‘Milotai kései’, ‘Alsószentiváni kései’) and an international grown cultivar ‘Chandler’ were involved. Based on preliminary results, cultivar ‘Tiszacsécsi 83’ had the highest frost tolerance during the whole period of examination, while frost susceptibility of ‘Chandler’ was the highest in the first two examination months, but one month before bud-breaking the frost hardiness of this cultivar was near to that of ‘Milotai 10’.