Study On Artificial Method Of Seeds Dormancy Breaking Of Setaria Sphacelata

Setaria sphacelata cv. Narok is one of the most excellent grasses, which is usedfor grassland production and ecological environment construction in subtropical andwarm temperate areas of south. Narok seed yield is low, and the seeds dormancyphenomenon is serious. The supply of seeds is not adequate to the demand, and itsapplication is restricted severely. In this experiment, Narok seeds produced in Yunnanprovince were used as the research object. On the basis of determining the rate ofseeds dormancy, seven kinds of methods of seeds dormancy breaking （mechanicaltreatment, KNO₃treatment, NaOH treatment, H₂SO₄treatment, HCl treatment, hotwater treatment, liquid nitrogen treatment） were designed. The effect of each methodwas analyzed by evaluation index: germination potential、 germination rate、germination index、vigor index. This research got conclusions as follow:1. Seed produced in Yunnan province purity was47.05%, germination rate was12.33%. Using TTC to stain, seeds of embryo was stained completely accounted for50.03%, seeds in different degree of dormancy accounted for37.70%.2. Mechanical treatment, including puncturing the whole seed, removing shell（naked seed）, puncturing the naked seed which could significantly improve Narokseed germination potential, germination rate, germination index, vigor index had goodeffect on seeds dormancy breaking. The result: puncturing the naked seed> nakedseed> puncturing the whole seed, which effect of puncturing the naked seed is thebest, germination potential was31.67%, germination rate was33.33%, germinationindex was0.16, vigor index was0.22.3. Seed in KNO₃of the concentration of0.6%⁰.8%for12³6minutes, Narokseed germination rate increased from12.33%to24.00%. Germination potential was20.33%, germination index was0.12, vigor index was0.14. 4. H₂SO₄treatment had effect on Narok seed dormancy breaking. But H₂SO₄solution must be at an adequate level of concentration for an adequate range oftreatment time. It is the best to seed in H₂SO₄of the concentration of50%for2minutes, germination potential was30.33%, germination rate was32.67%,germination index was0.16, vigor index was0.17.5. HCl treatment at an adequate level of concentration for an adequate range oftreatment time could improve seed germination potential, germination rate,germination index and vigor index. It is best to seed in HCl of the concentration of25%for4minutes, germination potential was30.67%, germination rate was35.00%,germination index was0.17, vigor index was0.29.6. Hot water treatment which could improve Narok seed germination potential,germination rate, germination index, vigor index had good effect on seeds dormancybreaking. It is the best to seed in hot water of70℃, germination potential was22.67%,germination rate was26.33%, germination index was0.13, vigor index was0.17.7. Liquid nitrogen treatment which could improve Narok seed germinationpotential, germination rate, germination index, vigor index had good effect on seedsdormancy breaking. It is the best to seed in liquid nitrogen for1minutes, germinationpotential was16.00%, germination rate was22.67%, germination index was0.11,vigor index was0.16.8. Comparison of each treatment, effect of treatment of seed in HCl of theconcentration of25%for4minutes is the best. Germination indices were significantlyhigher than those of control, which compared with other treatments had improved indifferent degree.