Winter hardiness study of new columnar apple varieties of the VNIISPK breeding

Abstract

Frost hardiness of new columnar apple cultivars of the All-Russian Scientific Research Institute of Fruit Cultures Breeding (VNIISPK) breeding was investigated in the controlled conditions by the way of modeling injuring factors of a winter period. As a result of the investigation the significant cultivar distinctions in hardiness to unfavorable temperature effects were observed. According to the results of the artificial freezing it was determined that in early winter the studied columnar cultivar samples showed high frost hardiness of buds and tissues. In middle winter buds and wood were more damaged by critical frosts; at the same time bark was more resistant in a majority of the cultivars. During thaws vegetative buds more suffered from the frost, but the main tissues kept frost hardiness. Late in winter all studied columnar apple cultivars showed high resistance of buds and tissues to recurrent frosts due to their ability to keep a hardening condition to low temperatures. Resistant cultivar samples were determined according to a complex of winter hardiness components. Columnar cultivars ‗Girlianda‘, ‗Yeseniya‘ and ‗Sozvezdiye‘ were characterized by the highest level of bud and tissue resistance according to all winter hardiness components.