| Corn is called"the king of feed"as the high yield and nutrition. Feed corn is used for the production of special variety of silage corn. At this stage in china, the core of the problem on feed is the issue of corn. Shannong feed corn No.7 is selected by Shandong Agricultural University, which is a cultivar of multi-axillary buds and multi-spikes, It possesses high whole-plant yield rapid growth, short growth period, high ratio of leaf to stem and biological output, high quality feed with good adaptability. The aim of this study is reasearch the safety of the production of Shannong feed corn No.7, and select a good seed coating agent,which can control seedlings, increse the number of tillers, control diseases and pests, increase yield. We also studied natamycin on controling of the Aspergillus flavus.1. The effect on protective function and yield of Shannong feed corn No.7 by three kinds of seed dressing formulations was studied, using indoor experiment, greenhouse potting and field trial respectively. Results demonstrate that Imidacloprid-tebuconazole(5%+0.4%) seed coating agent (the medicament and seed quality ratio 1:100) has a remarkable promoter action compared to another kinds of SD in plant height of seedling stage, the length of primary root and tiller. 5.4%imidacloprid-tebuconazole seed coating agent (the medicament and seed quality ratio 1:50 and 1:100) to Corn Rough dwarf and Sheath Blight control efficiency respectively to achieve 93.5%, 87.1%, 80.0% and 71.7%.The average yield reached 6891.9 kg/667m2 and the rate of increase production reached 11.5%.2. In vitro study it showed that imidacloprid-tebuconazole seed coating agent could increase the activity of disease resistance related enzymes in both above aerial and the underground parts of the seedings, with superoxide dismutase (SOD) specific activity being improved by 47.1% and 100.2%, and phenylalanine ammonialyase (PAL) specific activity being enhanced by 59.5% and 58.6% respectively; meanwhile, the content of malondialdehyde (MDA) being decreased by 54.0% and 26.2%, respectively. The activity of catalase (CAT) and peroxidase (POD) was also increased in different degree.The effect of 5.4% Imidacloprid-tebuconazole seed coating agent on the activity of disease resistance related enzymes increase obviously and promote seedling growth significantly.3. The inhibition of natamycin, cinnamal dehyde and prochloraz against A. flavus increased when temperature decreased, The activity was respectively enhanced by 2.23 , 1.52 and 1.81 times at 19℃when compared to 31℃. Between 15~33℃, Aspergillus sporulation is increasing rapidly. Inhibition is enhanced with higher concentrations of antiseptics. When 28℃, the natamycin concentration 100 mg / kg in corn and peanut seeds, sporulation significantly reduced, the inhibition rate reached 98.0% and 98.6% respectively.With the water content increasing in10%~20%, the antiseptics inhibition to aspergillus of aflatoxin was descend. Dealing with the peanut seeds absolute water content of 20% with natamycin 25mg/kg, The inhibition are still up to 52.99%. When natamycin concentration of 100 mg/kg, the inhibition of AFB1, AFB2 and the total aflatoxin in corn grains were 97.11%, 74.30% and 96.99%. In peanut seeds were 92.29%, 55.42% and 91.98%.4. After Aspergillus flavus were selected for 30 generation on medium by antiseptics, EC50 of natamycin increased from 1.4060mg/kg to 3.1301mg/kg, resistance is 2.15 times. EC50 of cinnamal dehyde increased from 5.2197mg/kg to 38.4138mg/kg, for 7.36 times the resistance. EC50 of prochloraz increased from 0.0359mg/kg to 0.0587mg/kg, a 1.64-fold increased resistance.5. Effect of natamycin on ergosterol biosynthesis in mycelia of A. flavus was tested through saponification extract and HPLC analysis. The results showed that the content of ergosterol decreased with the increase of natamycin concentration, with the inhibition rate of 93.26% at the concentration of 5.0μg a.i./mL 14 days after treatment. |
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