Analysis on the Phenotypic Variations of the Half-sib Progeny of Betula Platyphylla var.Mandshurica and Selection of Its Fine Individuals
Abstract
Betula Platyphylla var. Mondshurica is a geographical variety of Betula platyphylla with good adaptability,fast growth,fine texture,and a wide range of uses. In this paper the ex situ conserved forest of the half-sib progeny of Betula Platyphylla var.Mandshurica was the study object and the phenotypic variations of the characters including the tree height,DBH and crown breadth were studied with the method of continuous positioning measurement of fixed sample plots and the genetic effects of the half-sib progeny's quantitative characters were comprehensively evaluated,and fine individuals were widely selected based on the results. The results showed that there were some variations among the 4 characters of the half-sib progeny families including the tree height,DBH,east-west and north-south crown breadths and the mean variation coefficients were 4.39%,22.90%,21.23% and 25.20% respectively.The differences of the characters including the tree height,DBH and north-south crown breadth were highly significant while that of the east-west crown breadth was significant. The half-sib progeny's quantitative characters were highly controlled by the genes and have strong heritabilities with low genetic differentiation and high genetic gains. The heritabilities of the 4 characters were 0.983,0.755,0.666 and 0.796 respectively,and their genetic gains were 3.21%,13.49%,11.52% and 15.93% respectively. The family MRS03 was determined to be the finest with all the evaluation indexes and influence factors taken into account.