Studies On Genetic Variation And Adaptability Of Eucalyptus Cloeziana

Eucalyptus cloeziana is one of Eucalyptus species, which was introduced fromAustralia, it is a good saw timber, and it is suitable for cultivating as big-diametertimber. Provenance and family variation of growth and adaptation were analyzed onearly growth and seedlings. Greenwood density and basic density were analyzed on thebasis of 33 wood samples from the plantations with 11 provenances at age 17.Geography variation regularity of growth characteristics and wood properties ofeucalyptus cloeziana were also discussed. The major results were as follows.a. There was significant difference among provenances and families in height,diameter of breast height and volume, and rich variation within provenances andfamilies, and the heredity between their growth characteristics and timber properties isrelatively independent. Eucalyptus cloeziana's genetic improvement could be madefrom two respects of growth characteristics and timber properties at the same time.b. There was significant difference between provenances and families in survival rateand preservation rate. The mean survival rate and preservation rate of provenances andfamilies is 85.00%, 81.35% and 85.11%, 81.66%, respectively. The high survival rateand preservation rate of Eucalyptus cloeziana show that there are high adaptability tothe local environment, and significant difference among provenances and families insurvival rate and preservation rate show that the necessity and practicability by properselection.c. There was not significant difference between provenances in greenwood density andbasic density and with the control by heredity of under medium level. Lowerpotentialities of genetic improvement in basic density. The mean basic density forprovenances was 0.6514g/cm~3, which reached basic density criterion for saw timberand was suitable for cultivating as big-diameter timber.d. The basic density around pith is lower than around bark. Basic density is ascendingin line from pith to bark. This indicates that basic density is ascending with ages.e. Through early growth characteristics 8 provenances and 59 families werepreliminarily selected from 19 provenances and 119 families. The selected provenances'mean height, DBH and individual volume was 7.6m, 7.4cm, 0.0204m~3,respectively. The selected families'mean height, DBH and individual volume were7.57cm, 7.89m, and 0.0203m~3, respectively.And through autumn growth characteristics5 provenances were selected from 11 provenances, that is B47,B85,12195,14127 andD47.f. The relationship between height, height of branch and latitude, longitude wassignificant negative correlation, and crown was significant positive correlation. DBHand individual volume was not related to the latitude and longitude, greenwood densitywas significant negative correlation to latitude, and basic density was significantnegative to longitude.g. Through the analysis of test, the growth characteristics tendency of goodprovenances is: the north provenances are better than the south provenances, coastalprovenances are better than inland provenances. This is the same results as abroadresearch.