Introduction. For some species such as P. armeniaca, overcoming dormancy
may be problematic when cold requirements are not satisfied. Moreover, the different
positions of flower buds on the tree canopy and on the apical and basal portions
of twigs can influence their development. Sampling problems have not been extensively
studied. Therefore, the effect of different sectors (west and east), of different
heights (top and bottom) of the canopy and of twig portions (medium-apical
and medium-basal) on the break of dormancy in the apricot tree was evaluated.
Attention was also focused on floral anomalies in relation to the flower bud
position on the twig, in order to identify the least variable portion of twigs
and thus provide useful information for optimization of periodic bud sampling.
Materials and methods. Two cultivars of P. armeniaca with different chilling
requirements were chosen: `San Castrese' and `Orange Red'. The end of endo-dormancy
was evaluated from December to blooming time by traditional biological approaches,
such as increase in flower bud fresh weight and evolution of the bud phenological
stage, before and after 7 d under forcing conditions. In addition, the percentage
of floral anomalies was considered in relation to the flower bud position on the
twig. Results and conclusion. The results showed that canopy and twig positions
exerted different effects on the breaking of the flower bud endo-dormancy,
and some practical applications can be drawn from them for the best sampling
design inside the tree structure: the west orientation of the canopy and the
medium-apical portion of the twig were the best positions to obtain an earlier
active growth of buds, allowing the prediction of endo-dormancy breaking.
The analysis of flower anomalies showed considerable differences depending
on the position of the bud on the twig. High percentages of anomalous buds
were observed in the medium-basal portion of the twig, which could distort
the results on the evaluation of overcoming dormancy, due to a weaker growth
trend of flower buds.