TEMPERATURE AND BUDDING STIMULANTS IN BUD FLOWER DROP OF APRICOT (Prunus armeniaca L.) CP 90-4C SELECTION

Abstract

During dormancy, over three years flower bud drop on apricot tree (Prunus armeniaca L.) CP 90-4C selection was studied, on two, three and four years old planted pots. In the first year the trees were subjected to temperature treatments in growth cameras, one camera at low temperature (5±2ºC), other at high temperature (15ºC), and alternate temperatures (7ºC at night and ambient during the day, a week at 7ºC and a week at ambient temperature), on the alternate temperatures treatment 7ºC at night and ambient during the day, flowering was low as well as yield and fruit set. On the 3rd year, plants treated with 7ºC for 20, 30 and 40 days, the longer temperature treatments (40 days) showed the best results in flowering (44.6 %). Constant temperatures of 7ºC during a month and a half showed the best percentage of flowering with 63.93 and 55.72 % fruit retention, they also had the best flower quality with 86.5 % of flower 5 type, in scale 1 to 5. Flower bud drop was highest in the control, with the treatment of half month of cold and the one with alternate temperatures (low during the night 5±2ºC and ambient during the day) being 80.0, 72.1 and 81.1 %, respectively. The lowest percentage of flower bud drop was obtained with the treatment of one and one and half months at 7ºC with 59.2 and 35.8 %, respectively.