Response of some Malus mill. species representatives to extreme low temperatures in Baikal Siberia

The paper presents the results of study of maximal frost resistance of apple-tree varieties of Novosibirsk, Krasnoyarsk, Buryat, Canadian selection by the method of artificial freezing. The research found virtually all apple-tree varieties to withstand the temperature as low as -45оС without serious damage to bark, cambium and wood; with only Melba variety exhibiting significant bark damage. Apple-tree varieties of Buryat ACRI selection, regardless of cultivation location, demonstrated high tissue resistance to critical low negative temperatures. The investigated forms of Malus baccata L. Borkh, are characterized by high frost resistance in the middle of winter regardless of their location. Critical temperatures of -50о and -55оС proved lethal for Lada, Krasnaya Grozd’ varieties, as well as for Melba variety of Canadian selection.