Screening Of Selenium-enriched Millet Varieties And Improving Of Selenium Utilization Efficiency By Synergists In Beijing Suburbs

Millet is one of the important food crops in northern China.Selenium is one of the essential elements of the human body.Increasing the selenium content in millet can increase the selenium level in the diet of residents.Although there are a lot of studies on the improvement of selenium content in millet grains by exogenous selenium,there are few studies on the synergistic effect of synergist and selenium on the improvement of selenium enrichment ability of millet,as well as the transformation and distribution of selenium in millet.Beijing is located in the soil selenium deficiency zone from northeast to southwest of China.Therefore,in this paper,seven main millet varieties in Beijing suburbs were selected as the research objects,and high selenium-enriched millet varieties were selected.’Jinggu No.2’,’Jinggu No.3’and’Jinggu No.4’were used as experimental materials.Different synergists and different concentrations of selenium were sprayed on the leaves to determine the selenium content,amino acid and protein content,panicle traits and yield of millet.The synergistic effect of synergists and selenium was analyzed to clarify the distribution and transformation efficiency of selenium in plants during the absorption of millet.The main conclusions are as follows:1.Seven varieties of millet were sprayed with foliar fertilizer during the filling stage,and three treatments were set up:blank treatment（CK）,15.00 g·hm^-2 Na₂SeO₃ treatment（T1-2）,humic acid synergist+15.00 g·hm^-2 Na₂SeO₃ treatment（T2-2）.The millet varieties with strong exogenous selenium enrichment ability were’Jinggu No.2’,’Jinggu No.3’and’Jinggu No.4’.The grain selenium content,grain selenium utilization efficiency and intensification index were significantly higher than other millet varieties,while ensuring grain dry matter quality and yield.2.Four selenium levels and two synergists were sprayed on the leaves of’Jinggu No.2’,’Jinggu No.3’,’Jinggu No.4’during the filling stage,and 13 treatments were set up.When the concentration of Na₂SeO₃ was 15.00 g·hm^-2,the grain selenium content,selenium utilization efficiency and yield were significantly higher than other selenium concentrations within the safe range of selenium.Humic acid synergist was selected as the best synergist to improve the efficiency of selenium enrichment.Humic acid synergist increased the selenium content,grain selenium utilization efficiency and yield of millet by 30.48%～66.22%,50.40%～357.41%,2.48%～16.50%,respectively,compared with Na₂SeO₃ treatment,which was significantly higher than other synergists.At the same time,humic acid synergist increased the content of amino acids and proteins in grains by 1.82%～4.90%,1.72%～5.36%,respectively,compared with Na₂SeO₃ treatment.The grain selenium content and selenium utilization efficiency of the humic acid synergist+15.00g·hm^-2 Na₂SeO₃ treatment increased by 31.60%～66.26%and 50.40%～123.54%,respectively,compared with the 15.00 g·hm^-2 Na₂SeO₃ treatment.The humic acid synergist+15.00 g·hm^-2Na₂SeO₃ treatment of’Jinggu No.2’and’Jinggu No.3’reduced the amount of 1/3 Na₂SeO₃ compared with the 22.50 g·hm^-2 Na₂SeO₃ treatment.Grain selenium content increased by 41.50%,16.81%.It is concluded that humic acid synergist can reduce the application amount of Na₂SeO₃ and increase the selenium content in grains.3.The’Jinggu No.2’was sprayed with foliar fertilizer at the filling stage,and three treatments were set up:blank treatment（CK）,15.00 g·hm^-2 Na₂SeO₃ treatment（T1-2）,humic acid synergist+15.00 g·hm^-2 Na₂SeO₃ treatment（T2-2）.After foliar spraying of selenium fertilizer,the content of total selenium and organic selenium in plant shells increased compared with CK treatment,and the migration of selenium in shell-grain was increased.98.23%～99.44%inorganic selenium was transformed into organic selenium in millet plants 10 days after foliar application of selenium fertilizer.In the suburbs of Beijing,it is recommended to plant’Jinggu No.2’,’Jinggu No.3’,and’Jinggu No.4’as selenium-rich varieties.Spraying humic acid synergist+15.00 g·hm^-2 Na₂SeO₃ on the leaf surface of millet during grain filling stage can improve selenium enrichment efficiency,increase shell selenium content and selenium migration in shell-selenium,and increase grain selenium content.This paper provides a basis for the development of selenium-rich crops through rational fertilization.