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四、摘要条溃疡病是由棕榈疫霉引起的一种橡胶割面病,流行于大多数植胶国家,具有经济重要性。侵染割面的病原菌来自胶树树冠染病的胶果和叶柄;游动孢子借雨水的飞溅而散播。感病品系发病通常只有在胶树成龄和座果以后才被察觉出来。而且,除非环境条件有利和这个地区也存在接种源,否则,感病品系可能在田间试验中幸免感染,而被误认为条溃疡病的耐病品种,甚至是抗病品种。为了在品种选择阶段消除这类误差的发生,设计出一种用以鉴别某一橡胶品种对条溃疡抗病还是感病的简单方法。在胶树茎干离地150—175厘米处挖去一块直径2.5厘米的树皮,再用相同大小的、饱吸标准游动孢子悬浮液的消毒脱脂棉球嵌进这个空穴中,并用胶布封闭。每周一次观察其外表症状。然后除去接种点周围的树皮,记录其病害反应。在感病品系中,可以看见病害从接种点向上、下方扩展,木质部的染病组织呈条纹状,病区浅褐色。至于抗病品系,病害反应被局限于接种点周围的小范围,病斑呈深褐色。此法可在选种初期用以测定橡胶品系的先天抗病或感病性。
Fourth, the summary canker disease is caused by a Phytophthora palustrum rubber cut disease, epidemic in most of the plasticized countries, with economic importance. The pathogen that infects the cut surface comes from the gums and petioles of gum tree canopies; zoospores disseminate by the splash of rain. The onset of susceptible strains is usually only noticeable after the gum tree is mature and fruit harvested. Moreover, unless favorable environmental conditions and inoculation sources exist in this area, the susceptible strain may survive infection in the field and may be mistaken for a tolerant or even a resistant variety of the canker disease. In order to eliminate the occurrence of such errors in the stage of variety selection, a simple method for identifying the resistance of a certain rubber species to the ulcer is designed. Dig a bark of 2.5 cm in diameter from 150-175 cm from the stem of the gum tree, and insert it into the cavity with sterilized absorbent cotton balls of the same size, saturated with a standard zoospore suspension and closed with tape . Weekly observe the appearance of the symptoms. Then remove the bark around the inoculation site and record the disease response. In the susceptible strain, we can see the disease spread upward and downward from the inoculation point. The xylem infected tissue is in a stripe shape and the ward is light brown. As for the resistant lines, the disease response was confined to a small area around the inoculation site with a dark brown lesion. This method can be used early in the selection of rubber strains to determine the inherent resistance or susceptibility.