Comparison of natural and artificial epidemics of take-all in sequences of winter wheat crops
Comparison of natural and artificial epidemics of take-all in sequences of winter wheat crops
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DOI：
10.1111/j.1744-7348.1999.tb00887.x
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发表时间：
1999-12-01
影响因子：
2.6
通讯作者：
Hornby, D
中科院分区：
文献类型：
--
作者：
Bateman, GL;Hornby, D
在不同土壤类型上进行了连续6年（试验1）和连续3年（试验2）冬小麦田间试验。以全蚀菌（Gaeumannomyces graminis var.在第一批冬小麦作物播种之前或播种时，将在高压灭菌的燕麦颗粒上培养的燕麦（Trilingum）掺入一些地块的土壤中。实验I测试了在不同深度掺入相似量的接种物（212 kg ha（-1））。实验2在相同的浅深度测试了不同量的接种物。试验2中，早播（9月）、晚播（10月）和春季接种为附加处理，仅应用于第一茬作物。除季节因素外，接种后第一年的病害结果取决于接种量和接种位置以及播种日期。更深的接种导致更少的病害（实验I）。在实验2中，通过将接种物以足够的量（400 kg/ha（-1）或更多）浅加入，产生了严重的全蚀病。接种量较少（200公斤/公顷），病害较少，特别是在播种较早的地块。接种物处理之间的疾病的差异是最大的第一年，随后减少，特别是在播种早在第一年。在实验I中，第一作物暴露于人工接种物开发中度至重度疾病，疾病在随后的第二和/或第三作物是less. In第四作物的第二个高峰期的疾病发生，与第一个高峰期的序列没有添加接种物相吻合。此后，所有序列中似乎都表达了全取下降（Take-all decline）。在实验2中，在没有添加接种物的序列中，在第二作物的疾病高峰之后发生了枯萎病。当接种量超过400 kg/ha（-1）时，第一年病害严重，随后逐年减少。在接受人工接种的地块中，疾病不那么零散。然而，它仍然是不确定的，人工接种引起的严重疾病实现了早期发病的真正arrhythm.The感染性的顶部12厘米的土壤中的第一个3年的实验1，生物测定确定，取决于添加接种物的深度和数量的疾病在随后的作物。然而，在自然发生的高峰期的疾病严重程度（无论是接种或未接种的地块）的时间，它没有预测无论是疾病或pneumonia。流行病之间的差异和相似之处自然发展和那些发展从不同的数量和位置的应用接种物已被揭示。添加接种物的流行病学意义和潜在价值的人工创造的流行病的全蚀病在田间试验进行了讨论。
Winter wheat was grown for six successive years (Expt 1) and for three successive years (Expt 2) in field experiments on different soil types. Artificial inoculum of the take-all fungus (Gaeumannomyces graminis var. tritici cultured on autoclaved oat grains) was incorporated in the soil of some of the plots just before, or at, sowing of the first winter wheat crop. Expt I tested the incorporation of similar amounts of inoculum (212 kg ha(-1)) at different depths. Expt 2 tested different amounts of inoculum at the same, shallow depth. Early sowing (September), late sowing (October) and spring inoculation were additional treatments, applied to the first crop only, in Expt 2.Seasonal factors apart, the disease outcome in the first year after inoculation depended an amounts and placement of applied inoculum, as well as date of sowing. Deeper inoculum resulted in less disease (Expt I). Severe take-all was produced in Expt 2 by incorporating inoculum shallowly in sufficient quantities (400 kg ha(-1) or more). Less inoculum (200 kg ha(-1)) generated less disease, especially in earlier-sown plots. Differences in disease amongst inoculum treatments were greatest in the first year and diminished subsequently, particularly where sowing had been early in the first year.In Expt I, where first crops exposed to artificial inoculum developed moderate-to-severe disease, disease in subsequent second and/or third crops was less. In the fourth crop a second peak of disease occurred, coinciding with a first peak in sequences without added inoculum. Take-all decline (TAD) appeared to be expressed in all sequences thereafter. In Expt 2 in sequences without added inoculum, TAD occurred after a peak of disease in the second crop. Where 400 kg ha(-1) or more of inoculum were added, disease was severe in the first year and decreased progressively in successive years. Disease was less patchy in plots that received artificial inoculum. However, it remains uncertain that severe disease caused by artificial inoculation achieved an early onset of true TAD.The infectivity of the top 12 cm of soil in the first 3 yr of Expt 1, determined by bioassay, depended on the depth of added inoculum and amount of disease in subsequent crops. However, at the time of the naturally occurring peak of disease severity (in either inoculated or non-inoculated plots) it did not predict either disease or TAD.Differences and similarities amongst epidemics developing naturally and those developing from different amounts and placement of applied inoculum have been revealed. The epidemiological implications of adding inoculum and the potential value of artificially-created epidemics of take-all in field trials are discussed.