Variation in Fusarium graminearum and cultivar resistance to wheat scab
Variation in Fusarium graminearum and cultivar resistance to wheat scab
复制标题
DOI：
10.1094/pd-80-0975
复制
发表时间：
1996-09-01
期刊：
影响因子：
4.5
通讯作者：
Shaner, G
中科院分区：
文献类型：
--
作者：
Bai, GH;Shaner, G
了解病原菌毒力和品种抗性的变化对制定有效的小麦品种抗赤霉病育种策略具有重要意义。比较了来自中国和美国的6株稻瘟病镰刀菌（Fusarium graminearum）在9个不同抗病性小麦品种上的培养特性和毒力变化。这些菌株的培养特性和引起结痂的能力各不相同，但在品种抗性和病原菌毒力方面没有一致的特异性。因此，当地分离菌的混合物是筛选抗痂菌的合适接种物。在马铃薯葡萄糖琼脂上继代8代，毒力没有降低。在温室中，8个品种在3年内进行了5次试验，方法是在穗部的一个中心小花上接种印第安纳州分离的真菌。品种宁7840、苏麦49、福5114和苏麦3具有稳定的抗性。在不到20%的抗性品种中，真菌从接种后的小穗向未接种的小穗扩散，直到接种后12天传播才明显。易感品种Clark的所有植株均表现出侵染扩散，未接种的小穗在接种后8 d出现症状。穗顶的突然枯萎病可能是高感品种的一个重要特征。测定穗内赤霉病蔓延是一种稳定可靠的品种抗性评价方法。
Understanding variation in pathogen virulence and cultivar resistance is important for development of effective strategies for breeding wheat cultivars resistant to scab. Six isolates of Fusarium graminearum from China and the United States were compared for variation in cultural characteristics and virulence on nine wheat cultivars with different degrees of resistance to scab. The isolates varied in their cultural characteristics and ability to cause scab, but there was no consistent specificity of cultivar resistance or pathogen virulence. Therefore, a mixture of local isolates is an appropriate inoculum to screen for scab resistance. Subculturing the fungus on potato dextrose agar for eight generations did not reduce virulence. In the greenhouse, eight cultivars were tested five times over 3 years by inoculating one central floret in a spike with an Indiana isolate of the fungus. Cultivars Ning 7840, Sumai 49, Fu 5114, and Sumai 3 were consistently resistant. The fungus spread from the inoculated spikelet to noninoculated spikelets of resistant cultivars in less than 20% of the plants, and spread was not evident until 12 days after inoculation. All plants of susceptible cultivar Clark showed spread of infection, and symptoms appeared on noninoculated spikelets by 8 days after inoculation. Sudden blight on the top part of the spike may be an important characteristic of highly susceptible cultivars. Measurement of spread of scab within a spike is a stable and reliable estimate of cultivar resistance.