Early Selection Of Superior Provenances Of Pinus Tabulaeformis

Pinus tabulaeformis grows fast,has strong adaptability,it is resistant to cold and barren,and has good material quality.It is the main coniferous tree species in northern China.Therefore,it is necessary to select the provenances of Pinus tabulaeformis with good genetic traits.In order to shorten the breeding period and improve the selection efficiency,4-31-year-old Pinus tabulaeformis in Weichang County,Hebei Province were used as the test material.Under the three conditions of excellent,medium and poor,the tree height and basal diameter data of different forest ages were investigated to analyze the early and late correlation of Pinus tabulaeformis.Firstly,based on the original data the coefficient of variation of tree height and basal diameter of each forest age were calculated,then the image of the coefficient of variation of tree height and basal diameter with respect to forest age were plotted,therefore the best selection index was obtained by combining the phenotypic correlation coefficient of tree height and basal diameter.Then according to the the early efficiency formula the early selection efficiency was further determined.Under the premise of determined correlation between early and late growth and the early measurement indicators,growth traits were measured for several years to compare the early selection of good provenances.Results were as follows:Analysis of the relational image between coefficient of variation and the age of forest and the phenotypic correlation coefficient of tree height and basal diameter,correlation of tree height and basal diameter between late and early was obvious,which provided a theoretical basis for early prediction.At the same time the early primary selection period was determined as 4 years old,and the final selection period was 13 years old.According to the relevant information of the phenotypic coefficient,the best indicator for early selection was determined as the tree height,therefore the early selection efficiency was further determined.The plant height and basal diameter of 1 year old and 2 year old seedlings were significantly different among the 26 different provenances.The stem fresh quality and root dry weight of 1 year old seedlings were significantly different;photosynthesis rate,transpiration rate and leaf stomatal conductance were all present significant differences.The subordinate function values of plant height and basal diameter from 5 provenances were higher than those of local seed orchard provenance(Pingquan).The 5 provenances were Ningcheng in Inner Mongolia,Beipiao in Liaoning,Xixian in Shanxi,Heshun in Shanxi and Weichang in Hebei.There were significant differences in seedling height and basal diameter of 6-year-old 27 Pinus tabulaeformis provenances.Among them,the highest value was 160.3 cm from provenance no.2,whereas the largest basal diameter was 33.36 mm from provenance no.19.Using the subordinate function method to comprehensively evaluate and cluster analysis of the growth of 27 provenances for 6 years,and the results showed that the provenances from Zhouzhi County in Shanxi and the parent stand in Xixian County of Shanxi Province were better and more adaptable.Based on above experimental data,it was concluded that rankings of the excellent provenances from the early selection and the results obtained from the trials were all in the front,and there was great consistency.