皖豫高效抗逆大豆根瘤菌Y2-4的选育OA北大核心CSTPCD

In order to screen highly stress-resistant rhizobia suitable for soybean in Anhui and Henan provinces,we selected seven sampling sites in Anhui and Henan provinces to isolate soybean rhizobia from soybean root nodules,and identified them by phylogenetic molecular characterization,inoculating back to soybean,determination of resistance to stress,and evaluation of its growth-promoting effect through preliminary field inoculation trials.The results were as follows:621 soybean rhizobia strains were isolated,including 418 strains of Sinorhizobium(67.3％),which is the dominant soybean rhizobial in the region,198 strains of Bradyrhizobium(31.9％),and 5 strains of Rhizobium(0.8％,which could not effectively nodulated soybean).Compared with the reference strain CCBAU 45436,the chlorophyll SPAD value,nodule number and shoot dry weight of soybean inoculated with strain Y2-4 increased by 1.8％,15.5％and 9.8％,respectively.Moreover,Y2-4 had the ability to grow under 3％NaCl salt stress and 38 ℃ high temperature stress.The result of the initial field inoculation trials showed that inoculation of Y2-4 at three nitrogen fertilization levels,full nitrogen(225 kg·ha-1 of compound fertilizer,NPK ratio 15∶15∶15),reduced nitrogen 26.6％(225 kg·ha-1of compound fertilizer,NPK ratio 11∶15∶15),and no nitrogen application(225 kg·ha-1 of compound fertilizer,NPK ratio 0∶15∶15),could improve soybean yield.The"26.6％N reduction+Y2-4 inoculation"treatment increased soybean yield by 25.5％compared with"full N+uninoculation"treatment.The above results indicate that the excellent Y2-4 strain can be promoted and applied as an efficient and resistant rhizobial inoculum strain for soybean in some areas of Anhui and Henan provinces.