史密斯桉实生种子园建设初报

史密斯桉实生种子园由该树种的家系试验林经疏伐改建而成。在史密斯桉种源、家系选择试验阶段评选出优良种源2个，优良家系20个，优良种源中选率28．6％，优良家系中选率22．7％。种源蓄积量遗传力0．869，家系蓄积量遗传力0．609，单株遗传力0．986，进行单株、种源选择优于家系选择。优良种源遗传增益0．246，优良家系遗传增益0．276，家系平均实际增益45．3％。优良家系与较差家系木材密度无显著差异。家系试验林经两次疏伐改建为种子园后，每公顷保留林木340株左右。种子园促进史密斯桉植株开花结实试验的结果表明，经施肥及施用开花促进剂处理的家系开花结实率为对照的3倍，施肥及施用开花促进剂使植株开花结实提前，增加开花结实量有较好的作用。7．5年生，种子园个体平均开花结实率为24．6％，预计开花结实率每年将以15．5％的速度增加。开花结实率高的是18676、18688较差种源，开花结实率低的是18682、17131优良种源，较差种源开花结实率是优良种源的2．1倍。优良家系开花结实率65％，为全体家系平均开花结实率(28．6％)的2．3倍。较差种源比优良种源开花结实早，而在家系内是优良家系开花结实较早。

Construction of Eucalyptus smithii Seed Orchard

Eucalyptus smithii seed orchard is constructed through thinning and reconstruction of their family test stands. Two superior provenances and twenty superior families were selected in family selection test, which account 28.6% of total provenances and 22.7% of total families respectively. The timber volume hereditability of provenance, family and individual is 0.869, 0.609 and 0.986 respectively. The result indicates that individual and provenance selection is better than family selection. The genetic increment of superior provenance and superior family is 0.246 and 0.276 respectively. The actual average increment of family is 45.3%. There is no significant difference in wood density between superior and inferior families. There are about 340 trees per hectare left after orchard constructed through two times of thinning on family test stands. The results of test on promoting Eucalyptus smithii blooming and bearing show that fertilizer and blooming promoter are benefit for earlier blooming, bearing and increasing amount of flowers and fruits. The flowering and bearing percentage of families treated with fertilizer and blooming promoter is three times that of the control. The average flowering and bearing percentage of seven and half year old individuals in the orchard is 24.6% and it is estimated that the percentage will increase in the rate of 15.5% per year. The provenances with high flowering and bearing percentage are 18676 and 18688, which are inferior provenances. And provenances with low flowering and bearing percentage are 18682 and 17131, which are superior provenances. The flowering and bearing percentage of inferior provenances is 2.1 times that of superior ones. The flowering and bearing percentage of superior families is 65%, which is 2.3 times that of average of all families, 28.6%. Inferior provenances bloom and bear fruits earlier than superior ones. While within families, superior families bloom and bear fruits much earlier.