Abstract:

Based on four quantitative traits, height, diameter, volume and cellulose content of 240 families of Betula platyphylla, primary core collections were constructed using different sampling proportion(5%，10% and 15%), two distances (Mahalanobis distance and Euclidean distance) calculi, eight hierarchical cluster methods (Single linkage, Complete linkage, Median method, Centroid method, Unweighted pair-group method using arithmetic averages, Weighted pair-group average, flexible method and Ward’s method) and three sampling strategies (random sampling, preferred sampling and deviation sampling). The genetic variation of the quantitative traits among these primary core collections was compared by evaluating the mean difference percentage (MD), variance difference percentage (VD), coincidence rate of range (CR) and changeable rate of coefficient of variation (VR) of the traits. The results showed that the primary core collection was constructed with 10% sampling percent, Mahalanobis distance, preferred sampling strategy, and single linkage clustering method, and it was composed of 24 families of Betula platyphylla and the best representative of total germplasm.

Key words: Betula platyphylla, germplasm, core collection