Premature flowering in peach trees and its relaton with temperature: a case study

Abstract

In the year of 2013 was recorded an early and intense flowering in peach trees in atypical season, in the city of Urussanga, SC, Brazil. Twenty percent of the accessions of a peach tree collection showed full bloom in mid-April, when it usually occurs in July and August. The interval of temperatures between 16.0 and 19.0^oC and below 19.0^oC (13.0 to 19.0^oC) in a period of 49 days between February and March  were the most related to the anticipation of full bloom in that year, with correlations of -0.92 (p <0.01) and -0.85 (p <0.02), respectively. Although temperatures between 16.0 and 19.0^oC are not considered effective for endodormancy in many of the traditional phenological models developed for temperate fruits, some studies indicate that in genotypes with low cold requirement, they can perform this function. However, assuming a simultaneous accumulation of cold and heat, as proposed by parallel models of dormancy breaking, it is not possible to state whether this thermal band really had a vernalizing effect in the present case.