抗根腐線蟲及柑橘線蟲柑橘根砧之選拔與測試

The Selection and Test of Citrus Rootstocks as Hosts of Pratylenchus coffeae and Tylenchulus semipenetrans Cobb

近年來本省柑橘壽命日趨短暫，原因之一為線蟲之為害，治本之法為抗線蟲根砧之使用。國外雖有抗根腐線蟲根砧選出之報導，但種子遍求未果，加上各地線蟲有生理小種，抗性反應不一定類似，故由本省芸香科植物進行選種工作，以嘉義竹崎（南臺灣）之根腐線蟲（Pratylenchus coffeae）作接種源，每缽（含70 g培養基）接種根腐線蟲100條，三年下來，由33種芸香科植物之反應結果顯示黃皮（酸、甜二種）、月橘及麻豆文旦與紅文旦之雜交種具有抗性，又臺灣扁實（木黎）檬與晚侖夏雜交種、蜜柚、紅文旦、柳丁、椪柑及茹比多小花枳殼等6種植抹具中度抗性，其餘23種植株全為罹病性或高度罹病性，本省常用之酸桔及廣東（木黎）檬二種的砧木皆屬高度罹病性。另又進行測試在美已被確定對柑橘線蟲（Tylenchulus semipenetrans）具有抗性之三種枳殼及一種枳殼雜交種及臺灣常用砧木廣東（木黎）檬對關西地區（北臺灣）柑橘線蟲之抗性，結果顯示，飛龍、波馬麗、茹比多小花三種枳殼及4475-西出玫洛皆兵高度抗性，每缽所接之50O條線蟲無一存活，但廣東（木黎）檬則屬高度罹病性。故建議應進一步研究中度抗性至高度抗性植株作為本省柑橘栽培品種抗線蟲砧木之可行性，其中尤以茹比多小花枳殼對本省之柑橘及根腐二種線蟲皆具抗性，應特別注意其實用性。木研究成果之重要性為抗性品系的選出與確定，將可作為抗線蟲砧木育種之指標。

The nematode is one of the most important factors that shorten the lifespan of citrus in Taiwan. The basic way for preventing the nematode to the host was the usage of resistant rootstocks. Although there were selections for root-lesion nematode resistant rootstocks being reported by the U. S. researchers, yet there was no way to obtain those seeds. Also there were biotype problems for nematode in different geographic areas. Therefore a selection among the Rutaceae plants for root-lesion nematode resistance was conducted in Taiwan for the past three years. The Pratylenchus coffeae was taken from Chia-Yi (in southern Taiwan) and for every pot of seedling (in 70 g media) 100 nematode was innoculated. The results showed that among 33 selections tested, both sweet and sour wampi (Clausena lansium), common jasmine orange (Murraya painculata) and the hybrid of Madou pummelo X Red pummelo were all resistant to P. coffeae. Also C. depressa X valencia, Mee-yu, red pummelo, Liu-ting (sweet orange), Ponkan and Rubidoux small flower trifoliate were moderately resistant, while the remaining 23 selections were either susceptible or highly susceptible. Sunki and rangpur lime, the two most common citrus rootstocks used in Taiwan, were rated as highly susceptible. Tests were also carried out for 3 kinds of trifoliate and one trifoliate hybrid, which had been reported as all resistant to citrus nematodes in the USA, together with the Taiwan popular citrus rootstockrangpur lime. After innoculated with Tylenchulus semipenetrans from kwanshi area (in northern Taiwan), the results showed that Flying dragon, Pomeroy and Rubidoux small flower trifoliate together with 4475 Citrumelo all were highly resistant to citrus nematode, because no single innoculated nematode (500 nemas. per pot) was alive. while the rangpur lime was highly susceptible. It is suggested that further research should be done for testing the possibility of using the moderately to highly resistant selections as the rootstocks for cultivated citrus varieties in Taiwan. Especially Rubidoux small flower trifoliate had shown to be not only moderately resistant to root-lesion nematode but also highly resistant to citrus nematode. Special attention should be paid to its practical implications. The significance of this research is that the results can be used as indicators for breeding nematode resistant rootstocks.