Study of rhizosphere microflora in relation to varietal resistance or susceptibility of tomato to Fusarium oxysporum (Schlecht) f. sp. lycopersici (Saccardo) Snyder and Hansen

The relationship of soil microflora (fungi, actinomycetes, and bacteria) isolated from the rhizosphere of four different tomato varieties on the resistance and susceptibility of these varieties to Fusarium oxysporum lycopersici was studied under laboratory conditions. Four tomato varieties chosen for their resistant and susceptible qualities to Fusarium oxysporum lycopersici were used: Better Boy, Manapal, Bonny Best, and Ponderosa. The density of fungi, actinomycetes and bacteria in the rhizospheres and their antagonistic effect on F. oxysporum f. lycopersici were determined. The numbers of actinomycetes and bacteria were higher in the rhizospheres of the resistant varieties. Better Boy and Manapal, than in the susceptible ones. Bonny Best and Ponderosa. The numbers of fungi did not differ appreciably among varieties. The quantity of antagonism of actinomycetes and bacteria was significantly greater (P < .05) in the rhizospheres of the resistant varieties. Better Boy and Manapal than in the susceptible ones. Bonny Best and Ponderosa.