金华市水稻主栽品种纹枯病现状及经济阈值的研究

目的]调查金华市主栽水稻品种纹枯病田间发生情况，探讨其对水稻产量的影响，明确其经济闽值。方法]参照国家水稻纹枯病测报调查规范（GB／T15791—1995）进行病情调查，并测定不同水稻品种的各种产量性状；通过人工接种试验，研究不同接种量下水稻品种——金早47的病丛率、病情指数、水稻产量及产量损失率，并计算其在不同产量水平下的经济阈值。结果]金华市现有水稻主栽品种的抗病性为中抗水平以下，缺乏高抗品种；其中水稻金旱47为中抗，两优培九为中感，协优46则为感病。同一水稻品种在不同地区和不同生育期的抗性表现有所差异，水稻产量的损失随水稻品种抗病性的减弱而加重。孕穗期，金早47的病丛率和产量损失率成线性关系．要将产量损失率控制在7％以下，孕穗期的病情指数必须控制在4．2以下。结论]明确了金华市水稻主栽品种对纹枯病的抗性现状及其经济阈值．为水稻纹枯病的有效、合理控制提供了科学参考。

Study on the Current Situation of Resisting Rice Sheath Blight and Economic Threshold of Jinhua Main Cultivated Rice Varieties

Objective] To investigate the field occurrence of rice sheath blight of Jinhua main cultivated rice varieties,discuss the effect of the rice sheath blight on the yield,and clear the economic threshold.Method] The surveys were carried out referring to the rules for investigation and forecast of the rice sheath blight(GB/T 15791—1995),and the yield traits of different main cultivated rice varieties were determined;though inoculation experiments,the disease index,rates of disease bundle,yield and rate of yield waste by rice sheath blight of Jinzao 47 were studied at different inoculums sizes,and the economic thresholds of Jinzao 47 at different yield levels were calculated.Result] The resistances of the current rice cultivars in Jinhua city were under the level of moderate resistance,lack of highly resistant varieties.For example,the resistance of rice Jinzao 47 was moderate resistance,Liangyoupeijiu was moderate susceptibility and Xieyou 46 was susceptible;the same rice variety in different parts and developmental stages had different resistances.The loss of rice yield increased,while resistance of rice varieties weakened.There was linear relationship between disease index and rate of yield waste in booting stage of Jinzao 47,the disease index in booting stage must be control below 4.2 if the rate of yield waste supposed to be controlled below 7%.Conclusion] It clarified the current situation of resisting rice sheath blight and economic threshold of Jinhua main cultivated rice varieties,and offered the scientific references for the effective and reasonable control of the rice sheath blight.