烟草品种和打顶时期对烟草赤星病发病情况的影响

为探索不同烟草品种和不同打顶时期与烟草赤星病发病程度的关系，本研究采用裂区设计，以‘云烟87’、‘K326’、‘云烟97’等3个品种主处理，现蕾期、初花期和盛花期打顶3种不同的打顶方式为副处理，研究了不同品种对烟草赤星病的抗性和不同打顶时期对烟草赤星病发病程度的影响。结果显示，‘云烟97’对烟草赤星病的抗性最强，其次是‘K326’，抗性最弱的是‘云烟87’；‘云烟87’和‘K326’打顶时期以盛花期打顶对控制烟草赤星病的发病程度效果最好，‘云烟97’最适宜的打顶时期是初花期，现蕾期打顶效果最差。根据祁东烟区的实际情况，综合考虑烟叶的产量和质量，生产实际中最适宜推广的方式是‘云烟97’、‘云烟87’和‘K326’在初花打顶。

Influence of Varieties and Topping Time on Tobacco Brown Spot Morbidity

The paper aims to explore the relation of morbidity degree of brown spot with varieties and topping time of tobacco. An experiment was conducted with the split plot design to study the effect of different varieties and different topping time on morbidity degree of brown spot. Three varieties‘( Yunyan 87’,‘Yunyan 97’and ‘K326’) were taken as the main plot, and three topping methods (at squaring stage, initial flowering stage and full-bloom stage) were adopted as the split plot. The results showed that:‘Yunyan 97’displayed the strongest resistance to tobacco brown spot, followed by‘K326’, and‘Yunyan 87’had the weakest resistance. Topping at full-bloom stage had the best control effect on tobacco brown spot morbidity for‘Yunyan 87’and‘K326’, and topping at initial flowering stage had the best effect for‘Yunyan 97’, while topping at squaring stage had the worst effect. According to the practical situation of tobacco planting area in Qidong and with overall consideration of tobacco yield and quality, the optimum way is topping at initial flowering stage for‘Yunyan 97’, ‘Yunyan 87 ’and‘K326’.