Specificity of association betweenBacillusisolates and genotypes ofLolium perenneandTrifolium repensfrom a grass ndash; legume pasture

摘要

Specificity between plants and associated rhizosphere bacteria was investigated using species and genotypic mixtures ofLolium perenneL. (perennial ryegrass) andTrifolium repensL. (white clover) inoculated withBacillusstrains isolated from rhizosphere soil of the pasture plants. The genotypic identity of plants was controlled by using stolon tips (Trifolium) and tillers (Lolium) of three genotypes of each species collected from a 45-year-old permanent pasture. Inoculation of plants in the greenhouse withBacillusisolates that had coexisted in the field with theLoliumcomponent of aLoliumndash;Trifoliummixture increasedLoliumroot and shoot weight. Root and nodule weight ofTrifoliumin mixture regardless of its genotype was also higher when coexistentBacillusndash;Loliumcombinations were present. The presence of other coexistentBacillusndash;plant or plantndash;plant combinations did not enhance performance of either pasture species. The identity of theRhizobium leguminosarumbiovartrifoliistrains that formedTrifoliumroot nodules was unaffected by inoculation withBacillus.Key words:Trifolium repens,Lolium perenne,Bacillus, specificity, rhizosphere, yield.