Effect Of Using Iron In Calcareous Purple Soil And Molybdenum In Acid Purple Soil On Validity And Competitiveness Of Bradyrhi-zobium-peanut Studied By Gene Marker Technique

In this research, two types of soil which were lack of iron and molybdenum were used in pot experiment.Three strains of Bradyrhizobium Spr3-7,Spr4-5,Spr3-5 and their corresponding gene marker strains gusA3-7,gusA 4-5, gusA 3-5,celB3-7, celB 4-5 celB 3-5 with gusA and celB gene were selected to inoculate TianFu 9 peanut. Root nodule formed by gene marker strains had the ability to produce special color when reacting with detecting reagent. We used this characteristic to detect the effect of applying iron and molybdenum and their different level of iron and molybdenum on the symbiotic effectiveness and competitiveness of peaiait-Bradyrhizobium strains.Results showed that in calcareous purple soil because of available iron deficient, spraying iron, inoculatation, spraying iron + inoculation could all promote symbiotic nitrogen-fixtion effect of peaimt-Bradyrhizobium, their effect from higher to lower were spraying iron + inoculation> inoculatation > iron .Spraying 0.2% FeSO4.H2O solution could increase shoot dry weight, nodule weight ,total nitrogen content, total chlorophyll content, much more than 0.3% FeSO4.H2O solution. Correlation coefficient between total chlorophyll and total nitrogen, peanut yields, shoot dry weight, nodule weight were respectively 0.806, 0.637, 0.795 , 0.585.Spraying 0.2% FeSO4.H2O solution could promote competitive ability of peanut and inoculated Bradyrhizobium strains better than that of 0.3%, their competiveness in turn was Spr4-5>Spr3-7>Sp3-5. Ratio of occupancy detected by two gene marker techniques had no significant difference, average numerical value of them was respectively 79.46%, 75.62%, 74.41%.In acid purple soil because of available molybdenum deficient, effect of applying Mo + inoculation was better than inoculation , and inoculation was better than applying Mo. Effect of 0.4% NH4.MoO3.xH2O solution was better than 0.2% when they were applied alone ,while 0.2% NH4.MoO3.xH2O solution was better than 0.4% in inoculating Bradyrhizobium strains. Competiveness of Bradyrhizobium tested in turn was Spr4-5>Spr3-7>Sp3-5 .