02530naa a2200193 a 450000100080000000500110000800800410001910000110006024500830007126000090015450000200016352020140018365300230219765300140222065300130223465300110224765300200225877300580227810756142011-04-12       2010    bl uuuu     u00u1 u    #d1 aEpagri  aErger and Calcium Nitrate Concentration for Budbreak Induction in Apple Trees.  c2010  aISSN, 0567-7572  aApple trees grown in low chilling rest and break the dormancy later than those grown in colder areas. Low chilling shows symptoms such as low budbreak, which directly influences potential yield. Budbreak inductors are commercially used to overcome cold deficiency. Their effectiveness increases when at least 50% of the chilling requirement of a specific species or variety is naturally supplied. The lower the chilling the greater the concentration required for good budbreak and blooming. Too high concentrations may injure branches and fruiting organs. Erger, an inorganic nitrogen compound, has recently been introduced as an option for breaking apple dormancy. This work had the purpose of evaluating the effects of Erger and calcium nitrate concentrations on budbreak induction of ?Imperial Gala? and ?Suprema? (Fuji?s mutation). The experiments were carried out in Ca??ador - SC, Brazil (Lat. 26??46?31?S), in a RCB design, and 5 treatments with 6 replicates of one tree per plot. The treatments were control, standard (mineral oil 3% + Dormex?? 0.7%), and Erger + calcium nitrate at concentrations of 3, 5 and 7%. The variables evaluated were full bloom date, axillary and terminal budbreak, fruit set, fruits per cluster and mean fruit weight. The concentration of Erger + calcium nitrate had no effect on full bloom date, but these treatments anticipated it 24 days for ?Imperial Gala? and 7 days for ?Suprema?. Budbreak in axillary and terminal buds of the check was lower than in the other treatments up to 60 days after application. Budbreak did not differ between products and concentrations sprayed. Fruit set was not affected by Erger + calcium nitrate concentration. Sprayed trees with budbreak inductors had lower fruit set than the check trees of ?Imperial Gala?and ?Suprema?. The mean fruit weight was greater in all treated trees than in the control treatment. Erger 7% + calcium nitrate 7% showed phytotoxicity symptoms, but they were more intensive in ?Imperial Gala? than in ?Suprema?.  aBudbreak inductors  aDom??ncia  aDormancy  aMa????  aMalus domestica  tActa Horticulturae, Leuvengv. 872, p. 239-244, 2010.