THE INFLUENCE OF SEASONAL THERMOPERIODISM ON THE EMERGENCE OF THE ROOTSTOCK GRAPE VARIETIES FROM THE STATE OF ORGANIC REST
The effect of low temperatures in the autumn-winter period on the emergence out of the organic rest of the gra- pe varieties under the conditions of the foothill natural-wine growing region of the Crimea was studied. The investigated varieties: Berlandieri x Riparia Kober 5BB, Berlandieri x Riparia Co4, Berlandieri x Riparia Cracchunel-2, Berlandieri x Rupestris Ruggeri 140, Chasla x Berlandieri 41 B, Riparia Glouar de Montpellier, Riparia x Rupestris 101-14, Rupestris du Lo. A working hypothesis was accepted that the biological zero is not the temperature in degrees Celsius, namely the temperature of the transition between the activating biochemical processes of development and forced rest in the plant. The data of the carried out research make it possible to assert that the rudiments of the root system in the rootstock cuttings develop more actively under conditions of a relatively small accumulation of cold temperatures. From a technological point of view, knowing the peculiarities of the transition of plant cuttings from the period of activation of the development of root rudiments against the background of passive eyelet growth, it is necessary to apply the relatively early harvesting of the vine of rootstocks until it becomes capable of forming shoots under favorable conditions.