Tubajika K M, Russin J S, Harrison S A
Department of Plant Pathology and Crop Physiology.
Department of Agronomy, Louisiana State University Agricultural Center, Baton Rouge 70803.
Plant Dis. 1999 Jun;83(6):541-548. doi: 10.1094/PDIS.1999.83.6.541.
Studies were conducted to characterize spatial and temporal progress of bacterial leaf streak disease (Xanthomonas translucens pv. translucens) on susceptible (Florida 304) and moderately resistant (Terral 101) winter wheat cultivars. Epidemics were initiated with rifampicin-resistant strain 88-14 of X. translucens pv. translucens by establishing point sources of inoculum in plot centers. Incidence of bacterial leaf streak was assessed five times in 1995 and three times in 1996, starting from the first observation of leaf streak symptoms. Rainfall, temperature, and wind speed were significantly related to disease incidence, but relative humidity was not. The Gompertz model gave the best statistical fit for the progression of disease incidence over time. Average rates of disease progress (k) obtained from the regression of bacterial leaf streak incidence against time provided a good method of comparing the cultivars Florida 304 and Terral 101 and were consistent across locations. Bacterial leaf streak disease gradients were best described by the negative exponential model. Bacterial leaf streak incidence decreased with distance from inoculum source for both cultivars. Disease incidence on Terral 101 was near 0% at 2 m from the source, and disease incidence close to the source was consistently lower on Terral 101 than on Florida 304 at all growth stages sampled. This was not unexpected because the two cultivars differed in susceptibility. Disease incidence data were more useful than severity data in providing a good estimate of disease spread away from the source.
开展了多项研究，以描述细菌性条斑病（Xanthomonas translucens pv. translucens）在感病（佛罗里达304）和中度抗病（泰拉101）冬小麦品种上的时空发展情况。通过在小区中心设置接种点源，用抗利福平的X. translucens pv. translucens菌株88 - 14引发病害流行。从首次观察到条斑症状开始，1995年对细菌性条斑病的发病率评估了5次，1996年评估了3次。降雨量、温度和风速与发病率显著相关，但相对湿度则不然。Gompertz模型对发病率随时间的发展给出了最佳统计拟合。通过将细菌性条斑病发病率与时间进行回归得到的病害平均发展速率（k），为比较佛罗里达304和泰拉101这两个品种提供了一个很好的方法，并且在不同地点都是一致的。细菌性条斑病梯度最好用负指数模型来描述。两个品种的细菌性条斑病发病率均随距接种源距离的增加而降低。在距接种源2米处，泰拉101的发病率接近0%，在所有采样生长阶段，泰拉101靠近接种源处的发病率始终低于佛罗里达304。这并不意外，因为这两个品种的感病性不同。在估计病害从接种源扩散方面，发病率数据比病情严重程度数据更有用。
