烟草根结线虫削弱烟草对黑胫病抗病性的初步研究

本项研究目的在于探明烟草根结线虫(Meloidogyne incignita Chitwood)与烟草黑胫病(Phytophthora parasitica Var·nicotianae)之间的相互关系.试验用抗黑胫病品种——斯佩特G140(Speight Gl40)在烟草根结线虫与烟草黑胫病并发发严重的地块,用铁灭克(Temik)和瑞毒霉(Ridomil)分别防治根结线虫和黑胫病,或两药并用兼治两病,以不防治为对照.结果表明,烟草黑胫病的发生程度(y)与烟草根结线虫病情(x)之间具有正相关关系,相关系数γ=0.755,决定系数γ~2=0.570,说明本试验中烟草黑胫病病情有57%是由根结线虫引起的.进一步推导出经验回归方程y=6.753+0.395X,此方程可描述烟草根结线虫削弱烟草对黑胫病抗病性的量变关系,对防治决策有一定参考价值.

A Preliminary Study on Reduced Resistibility of Tobacco Plants to Black Shank Fungus Caused by Root Knot Nematodes

This study deals with the relationship between root knot nerafltode and black shank disease of tobacco plants in order to solve the problem of disease control ,Field experiment was carried out in Xuchang County, Henan Province in 1986. A resistant variety Speight G 14o was planted in a field where both pathogens existed abundantly and were distributed evenly. Ridomil and Temik were used to control black shank and root knot respectively or used together to control both diseases. The untreated plots were used as checks.The results indicate that there is significant positive correlation between the incidence of tobaacco black shank and the existence of root knot nematods. The correlation coefficient equals to 0.755**, and the determination coefficient r2= 0.570, which means, in this experiment, 57% of black shank disease was caused by root knot nematode. A regression equation was derived as Y= 6.753+ 0.395X where Y= disease index of black shank, andX= disease index of root knot nematode.This epuation expresses the quantitative relationship between both pathogens under experimental conditions mentioned above. It is helpful for us to make control dici-sions.