USDA-ARS, Department of Entomology & Plant Pathology, North Carolina State University, Raleigh, NC 27695, U.S.A.
Department of Agricultural, Food and Environmental Sciences, University of Perugia, 06123 Perugia, Italy.
Plant Dis. 2020 Nov;104(11):2928-2939. doi: 10.1094/PDIS-03-20-0527-RE. Epub 2020 Sep 8.
The duration of wheat susceptibility to infection has implications for risk forecasting, fungicide timing, and the likelihood that visible kernel damage may underpredict deoxynivalenol (DON) contamination. A field experiment was conducted to explore the impact of varying infection timings on Fusarium head blight (FHB) development in winter wheat. Trials in four successive years (2010 to 2013) in North Carolina utilized one susceptible and one moderately resistant cultivar possessing similar maturity, stature, and grain quality. Inoculum was applied in the form of sprayed conidia. In the first year, the nine infection timings were from 0 to 21 days after anthesis (daa), whereas in the following 3 years, they ranged from 0 to 13 daa. Infection progression was compared among inoculation timings by sampling spikes five to six times during grain-fill. Based on DON, percent kernel damage and kernel infection, and fungal spread as assayed via qPCR, the moderately resistant cultivar had at least a 2- to 3-day shorter window of susceptibility to damaging FHB infection than the susceptible cultivar. The results suggest that duration of susceptibility is an important aspect of cultivar resistance to FHB. In 2012, the window of susceptibility for both cultivars was extended by cold snaps during anthesis. After debranning in one year, the majority of DON was found to be in the bran fraction of kernels; there was also a trend for later infections to lead to a higher percentage of DON in the nonbran fraction, as well as a higher ratio of DON to FDK.
小麦易感染的持续时间对风险预测、杀菌剂施药时间以及可见的麦粒损伤程度是否低估脱氧雪腐镰刀菌烯醇（DON）污染的可能性有影响。本田间试验旨在探讨不同侵染时间对冬小麦赤霉病（FHB）发展的影响。在北卡罗来纳州连续四年（2010 年至 2013 年）进行的试验采用了一个感病品种和一个中度抗性品种，这两个品种具有相似的成熟度、株高和籽粒品质。接种物以喷雾孢子的形式施用。在第一年，九个侵染时间从开花后 0 至 21 天（daa）不等，而在随后的 3 年中，范围从 0 至 13 daa。在灌浆期间，通过五次到六次采样穗比较接种时间之间的侵染进展情况。基于 DON、籽粒损伤率和感染率以及通过 qPCR 测定的真菌传播，中度抗性品种对破坏性 FHB 感染的易感性窗口至少比感病品种短 2 至 3 天。结果表明，易感性持续时间是品种对 FHB 抗性的一个重要方面。在 2012 年，开花期间的寒潮延长了两个品种的易感窗口。在一年去壳后，大部分 DON 被发现存在于麦粒的麸皮部分；晚感染也有导致非麸皮部分 DON 含量更高的趋势，以及 DON 与 FDK 的比值更高的趋势。
