The Genetic Diversity Analysis Of Pueraria.lobata Resources & Effects Of Planting Density And Fertilization Rates On The Growth Characteristics In P.lobata

Pueraria lobata is a kind of perennial herbaceous liana of subfamily Papilionoideae in Leguminosae,many medical works have recorded its health care function.Meanwhile,P.lobata is a medicine food homologous plant published by the National Health Commission,which has both good nutritional value and strong health care efficacy.In addition to starch,protein,multivitamins and minerals,P.lobata has been found to contain puerarin,puerarin xyloside and soybean isoflavones,daidzein,amino acid,microelements,triterpenoids,etc.P.lobata is a good resource plant with broad development prospect.As the origin center of P.lobata in China,there are many kinds and wide distribution of P.lobata germplasm resources,but the genetic relationship among the germplasm resources is not clear.Therefore,on the basis of predecessors,this experiment further collects different places of P.lobata germplasm resources,through analyzing their genetic diversity,explores the genetic relationship of P.lobata from different sources,and provides support for the research,development and utilization of P.lobata.It is a kind of heliophyte,which is mostly creeping in the field and grows on the sunny slope.However,in the production and cultivation,it is required that P.lobata should be upright and its density should be increased,and its ecological environment such as light,temperature and water is very different from that in the field.For example,the mutual influence between plants leads to the decrease of light intensity.It is of great practical significance to study the effects of different planting density and fertilization level on the physiological and biochemical indexes of P.lobata.There are many reports about the effect of different planting density and fertilization level on plant growth,but the related research is not found in P.lobata,and the basic research is still very weak.Therefore,this experiment through setting different planting density and fertilization level,discusses the influence of growth characteristics and mechanism on P.lobata,in order to provide theoretical basis for the introduction and cultivation of P.lobata.The main results are as follows:1.Genetic diversity analysis of P.lobata from different sources14 primers with high polymorphism and good repeatability were screened out from100 ISSR primers.Through ISSR analysis of 20 P.lobata germplasms from different areas,110 bands were amplified,82 of them were polymorphic,the ratio of polymorphism was74.55%,the range of genetic similarity coefficient was 0.49-0.93,and the genetic diversity was relatively rich.G3（Hengfeng,Jiangxi）has the closest genetic relationship with G9（Shangrao,Jiangxi）.The genetic similarity coefficient is 0.93.The genetic similarity coefficients of G1（Dazu,Chongqing）and G2（Yangcheng,Shanxi）,G1（Dazu m,Chongqing）and G11（Suiyang,Guizhou）,G5（Qijiang,Chongqing）and G11（Suiyang,Guizhou）are all 0.90,while The relationship between G17（Fuling,Chongqing）and G19（Dianjiang,Chongqing）is far away,whose genetic similarity coefficient is only0.49,and the genetic similarity coefficient between G10（Wuzhou,Guangxi）and G17（Fuling,Chongqing）is also 0.49.The results showed that the germplasm resources of P.lobata from different areas had similar genetic background and some differences.The genetic differences were not related to the region,so the regional differences could not be considered in the introduction and cultivation generally.Secondly,the genetic distance between Chongqing Dazu（G1）and Shanxi Yangcheng（G2）and Guizhou Suiyang（G11）is the closest,which has a deep genetic background.At the same time,it was revealed that ISSR markers can effectively evaluate the genetic diversity of P.lobata germplasm resources,and it is one of the important tools to study the classification and evolution of P.lobata varieties.2.Effects of different planting density and fertilizer application amount on physiological and biochemical indexes of P.lobataThe experiment was designed as a two factor split area experiment.The main area was planting density,with 3 levels in total,800 plants·667 m^-2（A1）,1000 plants·667m^-2（A2）,and 1200 plants·667 m^-2（A3）.The auxiliary area is the amount of fertilization,and there are three levels:100kg·667 m^-2（B1）,200 kg·667 m^-2（B2）,300 kg·667 m^-2（B3）,the unified use of fertilizer is organic inorganic compound fertilizer:N（13）-P₂O₅（8）-K₂O（9）≥30%,and the plot area is 30 m²（1.5 m×20 m）,a total of 3 repetitions,the planting method was seedling transplanting.Studies have shown that different planting densities and fertilization treatments have significant effects on the physiological and biochemical characteristics of P.lobata,such as photosynthetic performance,the content of osmotic adjustment substances,antioxidant enzyme activity,endogenous hormone content,secondary metabolite accumulation and yield.Comprehensive analysis shows that the treatment of A2B3（T6）is the best income combination of cultivated P.lobata,that is,when the planting density is 1000 plants·667 m^-2 and the fertilization amount is 300 kg·667 m^-2,the comprehensive benefit of P.lobata reaches the maximum value.