VERNALIZATION AND SEED YIELD OF LATE HEAD CABBAGE IN DIFFERENT PHASES OF ROSETTE DEVELOPMENT BY APPLYING GA₃ IN VIVO

The seed of the head cabbage (Brassica oleracea var. capitata L.) in the continental climate is produced by bringing the plants into a certain stage of vegetative development, in meteorological conditions, in which the vernalization is possible. The vernalization is a physiological process of transformation of vegetative meristem tissue to reproductive, skipping in that way one phase of organogenesis – the head. This process takes place in conditions of prolonged exposure to low positive temperatures (winter and autumn in Serbia). Only certain number of plants during the cold period survives this transformation. The experiment was set up in four replications in three sowing dates: August 15, September 1 and September 15, with late genotype B at the Institute for Vegetable Crops in Smederevska Palanka. The nursery was planted on October 20, 2010 in vegetative space 70 x 50 cm or 28,500 plants ha^-1. The plants were treated two times with GA₃ in concentration 300 ppm, before and at the end of optimal temperatures for vernalization. The experiment proved the statistical significance of sowing terms to seed yield (P≤0,05) as well as the impact of interaction of sowing and the treatments to percentage of flourishing plants at both levels of significance (P≤0,01 and P≤0,05). The percentage of flourished plants was between minimal 35% and maximal 80%. The seed yield varied significantly from 194 kg to 1224 kg ha^-1.