5.5年生红锥半同胞家系生长变异及优良家系选择

In order to explore the growth and variation rules of half-sib progeny of Castanopsis hystrix screen the excellent families,and provide reference for genetic improvement,breeding and forestry production practice of the precious fast growing native tree Castanopsis hystrix.33 half-sib lineages from 3 experimental sites(Yulin,Liuzhou and Nanning)were selected as the research objects.The variation and genetic parameters of growth traits(DBH,tree height,east-west crown width,north-south crown width,tree volume per plant)were analyzed,and the interaction pattern between genotype and environment was analyzed and the influence of environmental factors on growth traits of Castanopsis hystrix was quantified.By estimating the best linear unbiased prediction(BLUP)value of the growth traits of each line at each test site,and combining with the factor analysis of principal component analysis,the excellent families were selected.(1)The growth traits of Castanopsis hystrix half-sib families were significantly differentiated.The Nanning half-sib families had advantages in DBH,tree height and individual tree volume,while the Liuzhou test site had advantages in east-west crown width and north-south crown width.(2)There were significant differences in location,block group,family and their interactions in single and multi-point ANOVA;The estimated genetic parameters showed that family heritability was greater than single plant heritability,and the coefficient of variation between families was greater than the average coefficient of variation within families,indicating that all growth traits were subject to high degree of genetic control,and the variation of growth traits was mainly inter-family variation,which was suitable for family selection.There was significant correlation between different traits in the family.(3)There were interaction effects between genotype and environment in growth traits,and the interaction patterns included B and D patterns,and the interaction was complex;Environmental factors significantly affected the growth of Castanopsis hystrix,among which tree height,tree height and tree volume per plant were significantly correlated with environmental factors.The relative importance of the environmental factors in diameter at breast height,tree height and tree volume per plant was the greatest,and the relative importance of latitude in east-west crown width and north-south crown width was the greatest.(4)The average practical gain and genetic gain of individual tree volume traits were 13.91%-25.45%and 7.92%-16.35%respectively,and the gain effect was obvious.The excellent family number 23 and 28 in Yulin and Liuzhou test sites,the excellent family number 32 in Yulin and Nanning test sites,and the excellent family number 5 in Liuzhou and Nanning test sites.There is abundant variation in growth traits of Castanopsis hystrix half-sib families among families,and the interaction between genotype and environment has a very significant effect on the growth of Castanopsis hystrix.The comprehensive selection of excellent families can provide excellent germplasm for genetic improvement,breeding and production practice.In the process of screening and demonstration,the interaction effect of environment,genotype and environment can be fully considered,and the families with good coupling with local environmental conditions can be selected according to local conditions.