Studies On The Plus Tree Progeny Test And Comprehensive Selection Of Pinus Tabuleaformis Carr

Pinus tabuleaformis Carr.is one of the most important native trees and timber tree species in the north of china because of rapid growth,good quality,drought and barren resistance.The area of natural forest of P.tabuleaformis in Shaanxi approximately account for 45%of the total natural forest in China.There are the richest genetic resources in Shaanxi Province.However,due to excess deforestation some good genetic resources were lost,forest species were not enough,and seriously affect the effectiveness of reforestation.In order to change this situation and improve the genetic quality of Chinese Pine we had carried out studies on selection of fine pine stands,good family,and superior individual in the region of fine seeds.Fine lines with high yield,good quality and strong resistance were selected by choosing a good genotype,increasing the frequency of beneficial genes,changing the structure of forest population,raising the level of genetic groups.34 plus trees were selected from the fine provenances of P.tabuleaformis in shaanxi.We collected the cones and got the seed,cultivated the seedling in the Container and constructed the plus tree progeny test plantations of P.tabuleaformis.We carried out the progeny test and genetic parameter estimation according to the families height,DBH,volume,form and other traits of the survey data,combined with modern breeding principles and quantitative inheritance analysis,thus choose the superior family synthetically.The result of the paper was the followings:(1) There was a extremely significant difference in 1-year-old seedling and hypocotyls height,and germination rates among the seven provenances,the 34 families and families within provenances.The seeding height in Lantian and Hua county was much higher,and the seed germination rates was higher in Hua county and Tongchuan provenances.However both the seeding height and seed germination rates were lower in Danfeng and Ningshan region.At 0.01 significant level,the seedling height difference between Lantian provenances and others reached significant level.The seeds height variation showing a lower-middle and northern part of the distribution of high-south-east trend.(2) The results of variance analysis and multiple comparisons indicated that different year of family had highly significant difference in height and diameter increment.The height and diameter of 5-year-old and 15-year-old tree reach significant and highly significant difference among the families.There was no significant difference of 20-year-old trees(P＞0.5).The height and diameter showed highly significant difference among different years old families. 5-year-old-tree'height,15-year-old-tree'height and DBH and 20-year-old-tree'DBH had reached significant and highly significant difference within the Provenance family. 20-year-old trees had a larger average growth in height in Ningshan,Danfeng and Lantian than in Huaxian,Tongchuan and Shangxian.The differences achieved a significant level of 1%.So,The provenances of Danfeng and Lantian were the better provenances because of the fast growth in height and DBH.(3) The height and diameter of families were significant and highly significant correlation. The inheritance correlation coefficients were larger than the corresponding phenotype correlation coefficients.The rank-related of height and height and DBH of families in seedling and young trees phase were not significant.The rank correlation coefficient between tree height and DBH of different ages reached a significant or very significant positive correlation.The different genetic traits were highly significant levels in DBH,height,volume and rate of preservation of 20-year-old.The relevant between stem form and other traits was poor,which may be inherited without other traits.The Genetic correlations between fruiting quantity and diameter at breast height,fruiting quantity and volume reached a significant positive correlation and had less to do with height.(4) The quantitative inheritance analysis showed that the heritability of seedling stage could reach 0.9.The height heritability of the period of young trees was about 0.6.The heritability of diameter and age have the same increasing trend.The coefficient of the genetic of height and the variation of phenotypic had gradually decreased with age.The genetic variation coefficient of the growth of stem was increased.Genetic gain of height with different age was gradually decreased with time changing.But the genetic gain of diameter was on the contrary. The heritability of 20-year-old tree's genetic parameters,growth traits and preservation was more than 0.6,which was called strong genetic.The heritability of fruiting quantity was 0.478, which is called moderate genetic.Stem form has the lowest heritability,which was much influenced by environment.(5) By the relevant heritability analysis,relevant heritability of the height,individuals volume and DBH is higher than their traits heritability.The relevant heritability of height and individuals volume is also higher than the heritability of height.Therefore,the indirect selection of both the DBH vs height and individuals volume and individuals volume vs height is greater than the direct selection.As a result,the stem form is independent genetic and the direct selection is best. (6) The path analysis showed that the DBH had the largest direct role on plant volume, which has reached 0.8224.The height has the largest indirect role on plant volume,which has reached 0.8087.The result showed that the height would mainly control the volume indirectly. And the effect of indirect controlling will achieved by the relevant genetic of the DBH. Fruiting quantity has a smaller direct role on plant volume.However it will have larger indirect role by DBH.Stem form and preservation have the smallest direct role on volume. The effect of preservation by DBH and height indirect controlling the volume could be up to 0.646.(7) A comprehensive evaluation of characters had been carried out on the families by the principal component and system clustering.The first principal ingredient was identified for the growth indicator and the second principal ingredient was the indicator of fruiting quantity and stem form.The 3,31 and 16 families were good families,which had great first and second principal components and good performance of the traits.The better families were divided into 6 types by the genetic distance of the principal component.â… ,â…¡andâ…¢families was much in growth,which can be used as breeding material of further genetic improvement.(8) We had evaluated the better family by index selection and determined the best index equation wasâ… = 0.3232X₁ + 0.7188 X₂-0.030X₄+ 0.1017X₅.According to the index equation,we also had determined the index value of the family and selected 8 better families, which were families 31,3,16,30,32,8,73 and 17.The selected families have varying degrees of improvement in growth traits than compared families.The height of selected families was 6.3%-15.5%higher than compared families,DBH was 11.1%-29.6%thicker and individuals volume was 26.5%-68.2%more.Fruiting quantity of all the selected families except for family 30 was also higher than compared families.The preservation of most of the selected families was 16%higher than compared families.