Analysis Of Forming Factors In Wheat Seed Vigor

Seeds are the most basic means of production of agricultural production.Use of highly viable seeds is an important guarantee for high and stable crops.The test uses 6 varieties of wheats with different vigor levels which are Xinong 889,Xiaoyan22,Zhoumai18,Zhoumai27,132H-2 in order to study the change law of wheat’s vigor under the different conditions of sowing dates,sowing rates,maturity stages,and to analyze the effect of sowing date and sowing rate on the ear bearing and yield structure of wheat.The results are as follows:(1)The germination potential,germination rate,seedling dry weight,germination index and vigor index of different wheat varieties are significantly different.The germination rate,germination potential,seedling dry weight,germination index and vigor index of seed tend to increase with the increase of seed maturity firstly and decline after reaching climax.The maturity at which germination potential and germination rate reach climax differs significantly among wheat varieties,while the maturity at which germination index and vigor index reach climax is similar among wheat varieties.However,they all stop to increase after around 34 days.(2)There are significant differences in the electrical conductivity of wheat seed,fresh seed 1000 grain weight,dry seed 1000 grain weight,the water content of fresh seed,the activity of peroxidase and the content of malondialdehyde.With the increase of seed maturity,the electrical conductivity and fresh water content of wheat seeds decrease gradually,and the conductivity gradually tend to keep stable under 20μS · cm-1 · g-1 around 22 days after pollination.Fresh seed 1000 grain weight which reaches it maximum after around 34 days and dry seed 1000 grain weight gradually increase.(3)Fresh seed 1000 weight and dry seed 1000 weight are significantly positively correlated with seed germination potential,seed germination rate,seedling dry weight,germination index and vigor index.The electrical conductivity,the moisture content of fresh seeds,the content of malondialdehyde content,SOD activity and CTA activity are significantly negatively correlated with seed germination potential,germination rate,seedling dry weight,germination index and vigor index.(4)Under the same sowing date,germination potential,germination rate,dry weight of seedling,germination index and vigor index of wheat seeds tend to decline with the increase of sowing rate.(5)Under the same sowing rate,the tiller number before winter,the maximum tiller number and the effective tiller number of wheat decline with the extension of sowing date.The grain number per head of wheat tends to increase with the extension of sowing date.The 1000-grain weight shows an inconformity with the change of sowing date.The grain yield gradually decline with the extension of sowing date.(6)Under the same sowing date,the tiller number before winter of wheat increases obviously with the increase of sowing rate.The maximum tiller number and effective tiller number tend to increase gradually but not obviously with the increase of sowing rate.The grain numbers per head,1000-grain weights and grain yields of 6 wheats show an inconformity with the increase of sowing rate.Therefore,a proper sowing rate should be chosen according to the genotype of wheat in order to raise yield...