Field Test and Lab Experiment on Control Efficacy of the Pathogen of Opium Poppy Mildew Karyotype comparison of poppy (Papaver somniferum) isoform collected from different areas in China Effect of 2,4-D on the antioxidative enzyme activities and lipid peroxidation in Opium Poppy (Papaver somniferum L.) Study on the Pathogen and Its Biological Characteristics of Opium Poppy Downy Mildew ISSR Genetic Diversity of Poppy Germplasms in Different Ecological Zones