| The paper choses E. urophylla×E.grandis clones as the research object, genetic varianceanalysis of 9 characters and synthetic selection of multiple characters were undertaken, at thesame time, the paper probed into the effects of growth and wood quality of E.urophylla×E.grandis with spacing and fertilizer treatments. Results are as follows:(1) There were significant differences in growth, form and wood quality charactersamong clones. Single volume of 11 clones were bigger than the total mean values of 25 clones,the clone DH33-27 was of the best growth, its 15-year-old DBH, height, single volume andbranch height was 25.0 era, 32.8m, 0.7722m~3, 20.1m; the clone DH32-28's form quality werethe best; for wood quality, the clone DH15-3 was the biggest outer wood density, the cloneDH33-20 was the smallest spiral grain.(2) Single volume and DBH, H showed strong positive relationships, the coefficient ofrelationship was more than 0.9, the relationship between DBH,height and branch height,branch,stem form was significant positive correlation, and the coefficient of relationship wasmore than 0.6; Pilodyn and DBH,volume,branch height,stem form,branch,bark thicknessshowed feebleness positive relationships, Pilodyn and H showed feebleness negativerelationships, and spiral grain showed negative relationships; the relationship between barkthickness and DBH,H,volume,branch height,stem form,branch,spiral grain showedfeebleness positive relationships, and Pilodyn showed feebleness negative relationships; spiralgrain and DBH,H,volume,branch height,branch,stem form,Pilodyn showed negativerelationships, and bark thickness showed positive relationships.(3) Phenotype coefficient variance of 9 characters were 7.92%～56.19%, genotypecoefficient variance were 7.22%～47.17%, clone repeatability were 0.7263～0.9480; Spiralgrain has the biggest coefficient variance, Pilodyn has the smallest coefficient variance andthe biggest clone repeatability, branch has the smallest clone repeatability.(4) Synthetic selection of multiple characters for E. urophylla×E.grandis clones by themethods of principal component selection and index selection, 25 clones were separated into10 clusters by principal component selection, picked out 7 clones with superior Syntheticcharacters, genetic gain of 9 characters were 15.52%, 9.89%, 39.51%, 24.65%, 24.65%,30.89%, 25.63%, 8.66%, 24.67%, 58.37%, clone repeatability of 9 characters were 0.8980,0.8395, 0.9166, 0.8583, 0.8043, 0.7263, 0.9480, 0.9070, 0.9036。(5) There were significant differences in mean values of DBH and growing-stock among differences spacing treatments, in 4.2a,6.3a,7.3a,8.3a,9.2a,12.5a year had a significantdifferences in height. Stand structure analysis of 13 years old E. urophylla×E.grandis,DBH≥26cm in spacing 5 stand there was 10%, in 20cm≤DBH＜26cm class, spacing 5(5m×3m) with the largest percent, nearly 80%; height of the stand, in 30m≤H class, spacing 5 withthe largest percent, more than 70%. Bigger spacing was not good for the growth ofE. urophylla×E. grandis, the spacing of 667stems/hm~2 and 883 stems/hm~2 was fit forE. urophylla×E. grandis middle/big diameter wood planting. There were significantdifferences only in bark thickness of E. urophylla×E. grandis wood quality. There weresignificant differences only in bark thickness of E. urophylla×E. grandis wood quality among6 spacing treatments. There were not significant difference among 6 spacing treatments for Alog; for B log, there were significant difference (a=0.05).(6) There was not significant difference in DBH among differences fertilizer treatments,only in 2.3 years old, there were significant differences in height and growing-stock (a=0.05).There were significant differences only in wood strength of E. urophylla×E. grandis woodquality.
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