Research Of Cold Resistant Agent Of Maize Seed

Seed vigor reflects potential ability of seed germination and seedling emergence in various conditions and is an important indicator of seed quality. Improving the vigor of seeds plays an important role in improving germination rate, withstanding the adverse environment, improving the competitive ability of seeds, enhancing cold resistance, increasing crop yield. Maize is a kind of thermophilous crop, has poor ability to adapt to low temperature. The northeast area is prone to cold and drought climate. Early sowing often encounter cold weather and late sowing is prone to drought. Study on the cold resistant agent to improve cold resistance of maize seed has important theoretical and practical significance for the early sowing,, rush-plant while the soil is damp, increasing the yield of maize. This paper selected optimal reagent to improve seed vigor firstly by using old Chuangqi518seeds as materials, through a single reagent, composite reagent priming and field verification tests. Using new Chuangqi518seeds as raw material, cold resistant agent on improving cold resistance of maize seeds by adding reagents of improving the cold resistance based on the chemicals was done. The cold resistant agent was further optimized by orthogonal test for finding the concentration ratio. At the same time, determination of morphological and physiological indexes related to the cold resistance mechanism of maize seeds and the field verification experiment were be done for providing scientific basis for the research and application of maize seed cold resistant agent. The results were as follows:1. Screening agent of maize seed vigor primingBy a single agent, polyethylene glycol (PEG), gibberellin (GA3) and calcium chloride (CaC12) of seed priming treatment, the result was that PEG can significantly improve the maize seed vigor, and GA3can significantly promote the growth of seedling. The germination rate of PEG increased by12.7%than the control (water treatment), but GA3, CaCl2treatment reduced by13.9%,46.8%. Vigor index of PEG treatment significantly increased by21.8%, while GA3, CaC12reduced by7.5%,48.8%. Plant height, GA3, PEG, CaCl2treatment increased by26.2%,12.8%,1.3%, effect of GA3and PEG was obvious; In PEG and GA3 composite initiator experiment, germination rate, vigor index, peroxidase (POD), catalase (CAT) were lower than the PEG (control) treatment. The results showed that, PEG was the best medicine to improve seed vigor of old maize seed.2. The field verification test of maize seed vigor priming agentThe seedling emergence rate, PEG increased by45.5%and137%than CK1(water treatment) and CK2(untreated), the average increase of91.3%,effect is significant. The plant height, dry matter accumulation, root shoot ratio, PEG treatment respectively increased by16.5%,22.6%,13.1%than CK1and CK2. The results of field test and laboratory test are consistent, PEG is the optimal seed vigor priming agent, can be used as the basis medicament for further research of maize seed cold resistant agents.3. Screening of maize seed cold resistant agentsSingle cold drug screening results showed that the germination rate of PEG treatment was slightly lower than the control (untreated), but higher than other treatments, and vigor index, seedling height and fresh weight of seedlings were significantly lower than other treatments. The germination rate of two dimethyl sulfoxide (DMSO), salicylic acid (SA) treatment was close to PEG, but the vigor index, seedling height and fresh weight was significantly higher than other treatments. Proline (Pro), calcium chloride (CaC12) correlation index was lower than control and PEG treatment.Experiment of composite medicament screening was be done on the basis of PEG, germination rate of maize seed of PEG, DMSO and SA combined treatment increased by80%and12.5%than CK1(water treatment), CK2(untreated), the average increase of46.3%. Germination potential respectively increased by87.5%and7.1%than CK1and CK.2, the vigor index respectively increased by90.5%and41%than CK1and CK2, the average increase of65.8%. Seedling fresh weight, plant height increased by15.1%,7.3%than CK1and CK2, peroxidase (POD), catalase (CAT) content increased by47.5%,40.8%than CK1and CK2. The combined treatment can significantly improve the cold resistance of maize seed.4. The optimization of maize seed cold resistant agentThrough the orthogonal experimental design, optimized concentration combinations on PEG, DMSO and SA was screened, its optimal concentration combination was PEG (20%), DMSO (0.5%) and SA (0.007%). The germination rate of combined treatment of maize seed respectively increased by39.4%,15%than CK1(water treatment), CK2(untreated), an average increase of27.2%. Vigor index respectively increased by41.7%and44.6%than CK1and CK2, the average increase of43.2%. Plant height averagely increased of9.3%than CK1and CK2. And the MDA content, conductivity of seedling respectively reduced23.5%,64.9%than CK2, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) content respectively increased by10.4%,42.7%and118%than CK2. The root vigor of seedling increased by48.4%than CK2, effect was significant. The content of chlorophyll, soluble sugar respectively increased by32.7%,34.5%than CK2, but the soluble protein decreased slightly (0.001%). This combination had a good effect on improving cold resistance of seeds.5. Application of field production of maize seed cold resistant agentThe germination rate of two years of optimization of cold resistant agent was significantly better than the control (untreated), which in2012increased by15.4%than the control, in2013increased by15.6%than the control, two years averagely increased by15.5%. Maize plant height, dry matter accumulation, root shoot ratio was higher than that of the control, but the corn seed and MDA content was lower than those of control. Maize seed cold resistance is obviously improved; The final yield performance of optimization cold resistant agent processing, increased by6.5%in2012, increased by6.3%in2013than control, two years averagely increased by6.4%. Optimization cold resistant agent had a certain effect on maize yield.