Study Of Imidacloprid Seed Dressing On Regulation To High Yielding Maize

It is universally acknowledged that maize is called “the king of feed” as thehigh yield and nutrition, and maize is used as the raw materials of industry andmedicines. It is important to promote stable and high yield of maize. Zhengdan958, breed by Dr. King Seed Co. Ltd. in Henan, that is characterized byroot-developed, fall-resistanced, drought-enduring, high yield, stable yield, wideadaptability. Imidacloprid, as a New nicotine kind of pesticide, is characterizedby high-efficiency, unique way of role. It can not only control the pest as well asreduce the environmental pollution in early stage of crop growth. With maize‘Zhengdan958’ as test material, through the sand bioassay experiment, pottedmethod and field plot experiment, It was tested by imidacloprid seed dressingincluding6different pesticide and seed mass ratio on the maizegermination,growth, control of plant diseases and insect pests and grain yieldafter treatment, and studied the adjusting mechanism, obtaining the appropriatedose of imidacloprid seed dressing, which can control seedlings, increse thenumber of tillers, control diseases and pests, increase yield.1.The sand bioassay experiment in this paper was determined by imidacloprid seed dressing including pesticide and seed mass ratio1.25:10000,2.5:10000,5:10000,10:10000,20:10000and30:10000tested on the maize seedgermination and seedling growth. The results indicated that all the treatmentsware safe to the maize seed germination and seedling growth. in the temperatureof28,5:10000ratio seed coating agent increased the seedling height, primaryroot length, secondary root numbers, leaf numbers, area of primary leaf, freshmass, dry mass, shoot ratio and chlorophyll content by1.18cm,2.85cm,0.35,0.28,0.74cm2,0.41g,0.055g,0.220and11.1%, compared with the contrastexperiment(treatment without pesticides), the effect was better than that testedon other treatment. In seed vigor study it showed that5:10000ratio seed coatingagent increased the germination, germination rate, germination index, vigorindex by38.9%,6.4%,27.6%and76.2%compared with the contrast experiment.The change was similar to activity of α-amylase after treated by differenttreatment in the process of corn seed germination, activity of α-amylase can stillmaintain a high level after7days treated by high pesticide and seed mass ratio,while the low ratio and the contrast decreased. With the germination days, thecontent of soluble reducing sugar increased, and it reduced after7days, but the content remained at a high level after seed dressing treatment.2.A plot experiment in this paper was determined by imidacloprid seeddressing including pesticide and seed mass ratio1.25:10000,2.5:10000,5:10000,10:10000,20:10000and30:10000tested on the high-yielding summer maizeseedling growth and the activities of nitrogen metabolism key enzyme andprotective enzyme activities and some other physiological indicators. The resultsindicated that5:10000~20:10000ratio seed coating agent increased the seedlingheight, secondary root numbers, number of leaves, fresh mass of abovegroundpart and underground part significantly. In vitro results showed that comparedwith the contrast experiment, glutamine synthetase activity, nitrate reductaseactivity, peroxidase activity, glutathione-s-transferase activity of leaves and rootsincreased significantly after treatment by pesticide and seed mass ratio5:10000~20:10000, and the chlorophyll content and roots activity increased,while the malondialdehyde content of leaves and roots decreased significantly.In addition to it had no promotion to the peroxidase activity of leaves and roots,and even inhibition.3.A field plot experiment in this paper was determined by imidacloprid seed dressing including pesticide and seed mass ratio1.25:10000,2.5:10000,5:10000,10:10000,20:10000and30:10000tested on the maize growth andyield of high-yielding summer maize cultivar Zhengdan958. in addition, testedon the nitrogen metabolism enzyme activities and protective enzyme activitiesof different growth stages. The results indicated that compared with the no seeddressing experiment, imidacloprid seed dressing treatment increased the grainyield significantly, with the increment being9.07%. In vitro results showed thatin the4-leaf stage and the small bell period, chlorophyll content, roots activity,nitrate reductase activity, glutamine synthetase activity, catalase activity,peroxidase activity and soluble protein content increased significantly aftertreatment by pesticide and seed mass ratio1.25:10000~10:10000, and the leafmalondialdehyde decreased significantly, compared with the contrast experiment;In addition to roots activity and malondialdehyde content effected significantly,the other physiological indices had no significant promotion, and even inhibition.In the silking stage and wax maturity stage,compared with the no seed dressingexperiment, Seed dressing in high doses was beginning to show a better role, butless than the low doses. 4.Control efficacy of imidacloprid seed dressing on maize aphides, cornborer and maize rough dwarf disease was investigated in field trials, the resultsindicated that control efficacy to maize aphides and maize rough dwarf diseasepesticide was well between seed mass ratio10:10000and30:10000, while thecontrol efficacy to the corn borer was not obvious.