桉树品系对青枯病抗性及其稳定性的研究

Studies on Selection of Eucalyptus for Resistance to Bacterial Wilt and Resitance Stability

通过剪顶包扎菌液接种、伤根淋灌菌液接种、 WFT培养接种测定结果与桉树当年新造林分青枯病自然发生率调查结果对比 ,青枯病菌对桉苗的致病力因接种方法不同而异 ,经模糊聚类分析表明 ,WFT接菌培养技术测出的结果更接近自然实际发病情况。试验表明 ,桉树不同品种、同一品种的不同种源、不同无性系 ,对青枯病菌的抗性不同。课题组通过 8年研究 ,在生产单位提供的 10 1个桉树品系中 ,已筛选出高抗品系 12个、抗病品系 14个、低感品系 2 6个。自 1994年起在粤、桂、琼三省区 ,生产上大面积推广这些高抗和抗病品 (种 )系 ,已直接造林 2万多 hm2 ,扩散面积更大 ,造林效果跟踪检查表明 ,这些林分的青枯病株率均在 1‰以下 ,受到生产者和经营者欢迎。试验和应用中发现部分抗病无性系随着在林木组培苗工厂连续繁殖使用年份增加其抗病性逐年出现下降 ,有些抗病无性系使用 3年以后 ,其抗病性就明显下降 。

The pathogicity of bacterial wilt( Pseudomonas solanacearun) to Eucalyptus seedlings varies with different inoculation method This was demonstrated by comparing the results of three inoculation methods (i e: inoculation by wraping up the bud cut seedling wiht bacterlal solution inoculation by irragating the damaged roots with bacterial solution and inoculation with WFT method )and the natural occurencing rate of bacterial wilt in nwely planted one year old Eucalyptus plantation Statisties and analysis show that the results with WFT inoculation method are more closed to that of the actual occuring situation of bacterial wilt in natural young forest It was also demonstrated in this study that the resistance ability of Eucalyptus to bacterlal wilt varies among different species、different seed sources and different clones After 8 years of study, 12 high wilt resistant varietes and clones 12 wilt resistant varieties and clones and 14 wilt resistant varieties and clones 26 lower wilt susceptibe varieties and clones are selected form 101 Eucalyptus varieties and clones provided by production units From 1994, more than 34000 hm\+2 Eucalyptus forest, are establisled directly with all these hign wilt resistant and with resistant clones and species and more than 67000 hm\+2 forest established indirectly with these wilt resistant vavieties and clones in Guangdong Guangxi and Hainan provinces Following investigation shows that the diseased plant rate in the established yong forest is bellow 0 1% and all these wilt resistant varieties and clones are widely welcome by Eucalyptus produtors and managers It was also showed in experiment and production that the resistance ability decline year by year as the wilt resistant varieties or clones are continuely propagated in tissue culture for years It shall be attach importance to the fact that the resistance of some wilt resistant varieties and clones decline remarkably after 3 years of aplication \ \