水稻粒黑粉病空间分布及抽样技术研究

 据6块田抽样调查,经频次概率拟合及聚集强度测定,水稻粒黑粉病田间分布以聚集型为主。其中有5块田既符合Neyman分布,也符合负二项式分布,仅有1块符合poisson分布。又经m^*-x回归检验和Taylor指数的"b"值计算,前者得出m^*=-0.445+1.02^*-x,r=0.977。后者为logδ²=log0.3769+1.2245log^*=-0.445+1.02^*-x。表明随病害密度升高,分布趋向均匀。以5种抽样方法与对照比较,差异均不显著,但以平行线抽样最接近对照且方便易行,可采用。抽样量为:#br#n=t²/D²(((α+1)/^*-x)+β-1)=53.302/^*-x+1.921依此可进行序贯抽样检索。田间垂直分布表现为穗基部发病重于中、上部,分蘖穗发病重于主穗。

THE SPATIAL DISTRIBUTION AND SAMPLING TECHNIQUE FOR THE KERNEL SMUT OF RICE

According to the results of sampling survey in six paddy fields and the test for goodness of fit and gathering extent,we concluded that the distribution of the kernel smut of rice Neovossia horrida(.Tak.) Padw,et A. Kahn was mainly of assembly pattern. Among the six paddy fields,the distributions were of Neymen type,but also of Negative binomial type in five paddy fields,and only one of them conformed with Poisson distribution. By using the regression test of m^* -x and the calculation of "b" value of Taylarexponent,resulted in m^*=-C.445 + 1.02x,y=0.977 and logs²=log 0.3796 + 1.2245logx respectively. The results showed that the ditributions tend to parallel with rise the disease intensity. Comparing the 5 methods of sampling with the contrast,the variances was'nt significance,but the sampling of parallel lines was most close to the contrast and easy to use. The formula of sampling amount was N=t²/D²(α+ 1/^*-x +β-1)=53.302/x+1.921. The venical distribution of the disease indicates that the disease at the base of spike was more severe than the middle and the top,while the disease of the tiller spikes were more severe than the main spikes.