We collected root nodules of 74 alfalfa plants in four different ecological regions in Jilin Province to survey rhizobia resources of ‘Gongnong No.1’alfalfa.The results showed that root nodules were generally located in 10 cm below the fibrous roots.The nodule number and the nodule weight in various places were influ-enced by the implantation time,the ecological type,and the soil type.81 fast-growing isolates from the root nod-ules were obtained.Eight rhizobial strains such as bc8,bc18,gzl59,da80,etc.were screened out by the tieback nodulation water culture,which were used to screen high efficient strains for ‘Gongnong No.1 ’alfalfa in the greenhouse study.The results showed that the after 75 days of greenhouse cultivation,most of nodules distribu-ted in 10 to 30 cm of the roots;the stem length,root length,number of leaves,dry weight and nodule number per plant of alfalfa inoculated with rhizobia were all increased significantly(P <0.05).Compared to the control,the stem length increased by 60.17% and 59.86% ,and the number of leaves increased 97.92% and 95.92% by in-oculated with yj34 and bc94,respectively;The root length was raised up 64.32% by gzl59;The dry weight of the plant was 288.24% and 157.14% higher than the control inoculated with gzl59 and bc54,respectively;Besides, the inoculated strains increased the nodule number per plant as well,the alfalfa plant formed more nodules by inoculated with strain yj34 than other test strains.Among 8 strains selected,strains bc18,yj34,bc94 and gzl59 on alfalfa were more effective than others;Of the four strains,the performance of three indigenous strains bc94 and gzl59 from its host of alfalfa grew in sandy loam soil in Baicheng and Gong Zhuling,yj34 from its host of al-falfa grew in dark brown soil in a ravine of Yanji exceeded the other strains estimated by plant growth.They are the highly-effictive rhizobial strains on ‘Gongnong No.1’alfalfa in Jilin Province.%在吉林省4个生态类型地区采集了74株不同建植年限苜蓿的根瘤,调查了“公农1号”紫花苜蓿根瘤菌株的分布情况。结果表明,苜蓿根瘤多数分布在根部10 cm 以下的须根；根瘤数量、重量受苜蓿建植年限、不同生态类型及土壤类型的影响较大。分离纯化所得的81株根瘤分离物经“公农1号”苜蓿水培回接结瘤试验,得到 bc8,gzl59和 da80等8个优良根瘤菌株；在温室条件下,对回接试验筛选出的8 个菌株进行土壤盆栽复筛试验,以期筛选出适合“公农1号”苜蓿生长的高效根瘤菌株。结果表明,根瘤分布在植株根部10~30 cm 处；在所有供试菌株中,菌株 bc18、yj34、bc94和 gzl59表现较为优良。菌株 yj34和 bc94对茎长和叶片数影响最大,茎长分别增加60.17%和59.86%,叶片数分别增加97.92%和95.92%；菌株 gzl59对根长影响最大,根长增加64.32%；菌株 gzl59和 bc94对提高植株干重贡献最大,其中,菌株 gzl59比对照增产288.24%；供试菌株对根瘤数的影响也很显著,接种菌株 yj34的苜蓿根瘤数相比其他菌株较高,达104.24%。综合分析,发现根瘤菌株 gzl59、bc94和 yj34较其他菌株表现突出,是吉林省“公农1号”苜蓿的高效根瘤菌株。
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