Family selection and evaluation of Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger based on stem analysis data at multiple sites

Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.

Introduction and Protection Suggestions of Biodiversity

Through the introduction of the concept,content,conservation significance and species value of biodiversity,the cognition of the research content,analysis methods and research directions of biodiversity was deepened.In view of the problems faced by biodiversity conservation at present,such as the accelerated disappearance of species,the unsound protection regulation system,the irrational spatial pattern of species protection,and the lack of long-term follow-up research,specific improvement suggestions were put forward,and have a positive guiding significance for future biodiversity conservation.

Prevention and Control Test of Semiaphis heraclei in Spring

[Objectives] The paper was to study the prevention and control effect of botanical pesticides on Semiaphis heraclei at different temperatures. [Methods] When the daily average temperatures in spring were 15 and 20 ℃, the control effects of 0.3% azadirachtin EC 500 times dilution and 0.3% matrine AS 1 000 times dilution on S. heraclei were studied. [Results] When the daily average temperature was 15 ℃, 0.3% azadirachtin EC 500 times dilution had relatively good control effect on S. heraclei, with a long duration. The prevention and control of S. heraclei in spring better controlled the population quantity of S. heraclei fundatrix and reduced the degree of harm. [Conclusions] The study provides a basis for the pollution-free control of S. heraclei in the green space of parks.