(42(1):46-52)Clonal Propagation of Phytophthora cinnamomi Resistant Rootstock of Avocado (Persea americana Mill.)

本文比較‘Duke 7’、‘Duke 6’、‘G6’、‘G22’，等酪梨病砧木品系繁殖的方法，包括砧木品系接穗嫁接於實生砧之成活率、其接穗萌發之枝條白化處理後之存活率、白化存活枝條經環狀剝皮處理及高壓後生根率等。結果顯示參試品系中以‘Duke 7’接穗之嫁接成活率最高，達71.0％。萌發枝條白化處理後之存活率以‘Duke 7’的最高，達50％。已白化存活枝條經環狀剝度處理及高壓後，‘Duke 7’與‘G6’的生根率達50％，‘G22’的則為0％。利用此方法，通常高壓後六個月內‘Duke 7’及‘G6’之接穗萌發枝條於靠近接合部之莖表面可有不定根之形成。再六個月後可切離原植株得長根新植株，將其盆栽於介質後可成活。參試品系中以‘Duke 7’之繁殖效率較佳，達17.8％。 In this report, methods of propagating resistant varieties, including ‘Duke 7’, ‘Duke 6’, and ‘G22’, was compared. Among the scions of ‘Duke 7’, ‘Duke 6’, ‘G6’ and ‘G22’, grafted to seedling stocks from unkown parents, scions of ‘Duke 7’ had highest percent of successful graft unions of 71.0%. After etiolated growing shoots had 50% survival in ‘Duke 7’ Among air layerd shoots, which had been etiolated and girdled before, rooting shoot percent in ‘Duke 7’ and ‘Duke 6’ both had 50%, while that in ‘G22’ only 0%. In general scions of ‘Duke 7’ and ‘G6’ varieties could had adventitious root formation from stem surface of shoot above graft union in six months after layered by using this method. After following six months new plant growing on its own roots could be got by cutting just below the adventitious root initiating part of ths rooting shoot. Rooting plants could grow vigorously after potted in plastic pots. Among tested varieties, ‘Duke 7’ had highest propagation efficiency of 17.8% with this method