Diversity Of Indigenous Rhizobia Of Soybean And Peanut In Hainan And Its Efficient Growth Promotion And Screening Of Specific Strains

Adequate forage supply is the basis for the development of animal husbandry.Due to the low economic benefit of forage cultivation,forage production in Hainan is not matched with the development of animal husbandry,especially the shortage of leguminous forage is serious.Hainan is the advantage of leguminous crops production area,plant area of 6484hectares,peanut and soybean is a kind of area is the largest species,the straw crude fat,crude protein and carbohydrate content is higher than that of common corn and wheat straw,protein digestibility and digestible energy were higher than rice,corn,barley straw,is of high quality protein feed.Inoculation of legume with efficient rhizobia could not only increase yield,but also significantly increase stem and leaf yield and crude protein content.At present,no suitable rhizobia can be inoculated for soybean,peanut and other leguminous crops in Hainan.This study collected different regions of hainan separation and identification of peanut,soybean nodule,determine its classification status,research the inoculation of different strains of soybean,peanut straw forage value,the influence of different strains were determined resistance to salt,acid,aluminum toxicity and secretion of auxin features,for the leguminous crops provide efficient strains in different areas.The main results are as follows:（1）A total of 59 nodal samples were collected from different areas of soybean and peanut in Hainan Province,and 59 cultures were isolated and obtained.After Gram staining and 16Sr DNA series determination,26 strains were identified as Bradyrhizobium,which were clustered into 6 groups on the phylogenetic tree with the known strains.（2）The most effective strains matched with soybean were D10,D7 and D2,which could increase the yield of stem and leaf by 2.49-4.87 times and the content of crude protein by 1.17-1.37 times after inoculation.H7,H6 and H2 were the most effective strains to match peanut.After inoculation,the yield of stem and leaf was increased by 1.02-1.24times,and the crude protein content was increased by 1.03-1.14 times.（3）The salt-tolerant,acid-tolerant,aluminum-tolerant and auxin secreting abilities of the rhizobia were determined qualitatively and quantitatively.Among the three strains isolated from peanut,H1 had the strongest salt-tolerant and could grow in the mediumwith Na Cl concentration of 0.4 mol·L^-1,followed by H2 and H3.The optimal growth p H of the three strains was less than 7.0,indicating that they were eosinophilic to some extent.The growth of strains H1 and H2 was not affected by p H change,and the inhibition of H3 was obvious at p H8.0,which was basically consistent with the soil p H condition of the collection site.All the three strains could grow under 200μmol·L^-1Al³⁺concentration,and the growth of H2 strain was greatly affected by Al³⁺concentration.Among the 7 strains isolated from soybean,D3 had the highest salt tolerance,followed by D5,and all of them could grow in the medium with Na Cl concentration of 0.4 mol·L^-1.Rhizobium D1,D2,D4,D5,D6,and D7 all have some eosinophilic properties.D3 is more suitable for neutral environmental conditions,which is basically consistent with the soil p H condition of the collection site.The growth of rhizobia D3 was less affected by p H,followed by strain H4.All the 7 strains could grow under the Al³⁺concentration of 200μmol·L^-1.Al³⁺concentration change had little effect on strain D3 and D4.All the 3 strains isolated from peanut and 7 strains isolated from soybean could secrete IAA,and the H3strains isolated from peanut had the strongest secreting ability,followed by H2 and H1.The rhizobia isolated from soybean had the strongest secreting capacity of D7,followed by D6.