本研究以選拔自栽植於林業試驗所六龜分所之九年生已具開花結實能力的玫瑰桉與尾葉桉雜交種56單株母樹為材料，進行扦插繁殖試驗，結果顯示：扦插1個月後開始發根，有13個單株（佔23.2%）的插穗發根，已發根單株部分之平均發根率為12.7%，差異極顯著；至5個月時有23個單株（佔41.1%）發根，已發根單株部份之發根率為5.0-82.5%，平均發根率為31.1%，差異極顯著。各單株發根率可依趨勢歸為四類：（一）初期即較大量發根，且最終發根率高，計有6單株（佔26.1%）；（二）最初發根數少，然後期發根率較明顯昇高者，含6單株(26.1%)；（三）初期僅少數發根，最後發根率亦低，佔3單株(13.0%)；（四）其他8單株(34.8%)發根遲緩而零星，且發根率極低。另由此可發根的23單株中選擇較早發根的16株為試材，進行不同時期扦插繁殖之比較，結果顯示：10月份最適於雜交桉之扦插繁殖，其次為1月及7月，而以4月份之扦插發根率最低，差異極顯著。
Cuttings were collected from 56 trees of 9-yr-old Eucalyptus grandis x urophylla grown in the Liukuei Experimental Forest of the Taiwan Forestry Research Institute. A vegetative propagation test revealed that rooting capability of cuttings differed significantly among individual trees. After 1 mo, cuttings from 13 of the 56 tress (23%) had rooted with an average rooting percentage of 13%. At the end of the 5th month, cuttings collected from 41% of the trees had rooted. Rooting percentages of cuttings varied among trees, ranging from 5 to 83%. According to the trend of rooting capability, 23 trees were classified into 4 categories. Cuttings from 6 of the 23 trees (26%) maintained high rooting percentage from the beginning to end and were classified into the 1st category. The 2nd category contained 6 trees in which cuttings were characterized by low rooting percentages at the end. Another 3 trees (13%) were grouped in the 3rd category in which cuttings showed low rooting abilities from beginning to end. The remaining 8 trees (35%) produced cuttings with low rooting percentages, mostly rooting at uncertain time late in the experiment. In different seasons of the rooting experiment, cuttings were collected from 16 of the 23 trees. Significant differences were found in rooting percentages among cuttings collected in different months during the year. The results showed that a better time for the rooting of cuttings collected from mature E. grandis x urophylla trees was in October rather than in January, July, or April.
