Development of young pear trees and occurrence of first flowering: A varietal comparison

International audienceThe development of young pear trees was studied in a collection of varieties with diverse branching habits by establishing a precise description of their architecture over the first two years of growth. The objective here was to test growth, branching, and the final dimensions of the shoots as predictors of tree capability to enter into a reproductive phase in the third year. Nine pear cultivars (Pyrus communis L.) grafted on BA29 rootstock were grown with a minimal training system. Tree structure was described over the first two years of growth, and flowering occurrences were counted in the third year using AMAPmod methodology. Linear multiple ascendant regressions were constructed with different sets of explicative variables to explain the number of flowering occurrence. The results show clear differences between the cultivars, those examined being divided into two categories based on whether growth was greatest in the first or second year. The most accurate predictive variable of the flowering occurrence was the difference in the number of sylleptic laterals over the first two years of growth. The physiological reasons for this correlation are discussed. This result suggest that the difference in sylleptic laterals between the first two years of growth could be evaluated in breeding programmes to select the genotypes on the length of the unproductive period