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Studies on double strain occupancy of nodules and the competitive ability of Rhizobium trifolii on red and white clover grown in soil and agar
Author(s) -
BROMFIELD E. S. P.,
JONES D. GARETH
Publication year - 1980
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1980.tb03895.x
Subject(s) - biology , rhizobia , strain (injury) , agar , inoculation , rhizobium , agar plate , horticulture , botany , symbiosis , bacteria , genetics , anatomy
SUMMARY An investigation concerning double strain occupancy of nodules and the competitive ability for nodulation of Rhizobium trifolii strains 7A str r and 32 spc r was carried out using red and white clover varieties grown in agar and soil. Only two nodules of the 498 typed from plants grown in soil contained both inoculated strains and none of those analysed by the replica plating technique were formed by both 32 spc r and an indigenous strain. In contrast, plants grown on agar produced between 17% and 25% doubly infected nodules. Strain 32 spc r was more competitive for nodulation than 7A str r both in soil and agar. Indigenous rhizobia in soil were highly competitive for nodulation with the introduced strains; increasing the density of the inoculum resulted in an increase in the proportion of nodules occupied by the inoculated strains. The strains used as mixed inocula in soil were less successful in nodulation than the same strains used as pure inocula. The results also indicate that there was a host effect on the nodulation success of 7A str r .