Selection of superior families of Pinus massoniana in southern China for large-diameter construction timber

This study addresses the increasing demand for large-diameter production timber,and considers the time and space variability of half-sib families of Pinus massoniana.Height,diameter at breast height(DBH)and timber volume of 440 open-pollinated half-sib progeny families were investigated in 14 progeny trials in different years and production regions.An evaluation of the genetic variation of all half-sib families was carried out during the sustainable rapid growth period and individual volumes were characterized as a major index.ANOVA analysis showed that there was considerable variance in the growth traits of most families in different years and on different sites.The variations caused by temporal and spatial changes of the mating system required three selection methods for analysis.The results show that there were differences among the heritabilities of different growth traits by different halfsib progenies.Average heritability values of height,DBH and volume were 0.33,0.34 and 0.36,respectively.Fortyfive superior families were selected in every progeny test,12 were selected in progeny trials by different years and five in different habitat progeny trials.Three superior families(Gui GC553A,Gui GC414A and Gui GC431A)were selected,although in different years and production regions.The genetic gains of timber volume of these selected r families ranged from 1.20 to 47.00%,which could provide a foundation for superior wood property selection and serve as material for seed improvement and extension in surrounding areas.

Benefit Assessment on Early Tapping of Pinus elliottii

The early growth of Pinus elliottii is rapid,so how to make Pinus elliottii generate economic benefit as quickly as possible is becoming increasing important.We conduct tapping test on man-made forest of perennial Pinus elliottii in Huashan forest farm,Huanjiang Maonan Autonomous County,Hechi City,Guangxi Zhuang Autonomous Region.The results show that the economic benefit of early tapping of Pinus elliottii is obvious,with high profitability;NPV(16 089.13)and IRR(39.2%)of forest stand tapped are much higher than that of forest stand not tapped;at the same time,it can bring considerable demand for labor,with good social benefits;tapping has a certain effect on the growth of Pinus elliottii,and turpentine production is closely related to the trunk diameter.

Roles of hormones,calcium and PmWRKY31 in the defense of Pinus massoniana Lamb.against Dendrolimus punctatus Walker

Dendrolimus punctatus Walker is a major pest affecting Pinus massoniana Lamb.forests and can cause serious economic and ecological losses.WRKY transcription factors play important roles in coping with various environmental stresses and plant responses against herbivorous insects.However,the mechanisms underlying the actions of WRKY in the defense responses of D.punctatus in P.massoniana are still unclear.Our previous study provided evidence that WRKY plays an important role in the insect resistance of P.massoniana.In this study,the treatments of exogenous hormones and Ca^(2+) increased the concentrations of endogenous hormones,and terpenoid synthases in P.massoniana effectively improving its resistance to D.punctatus.After analyzing the WRKY family of P.massoniana,PmWRKY31 was selected and studied.A direct interaction between PmWRKY31 and PmLp8 was observed by yeast double hybridization assay.Gene expression analysis showed that treatments of exogenous hormones and Ca^(2+)induced high PmWRKY31 expression.The expression pattern of PmWRKY31 was different under treatment of MeJA compared to those of GA,ABA and SA.These results indicated that PmWRYK31 and PmLp8 interacted with each other to promote the expression of terpenoid synthase genes and increase the content of terpenoid volatile substances by regulating the gene expression of hormone signaling pathways,to improve the ability of P.massoniana to resist D.punctatus,providing theoretical support for the involvement of WRKY transcription factors in enhancement of the insect resistance of P.massoniana through their regulation of hormone signaling.