Effect of inoculation with nitrogen-fixing Klebsiella on potato yield

A significant positive effect on yield of potato cultivars was obtained after inoculation with Klebsiella mobilis strains CIAM880 and CIAM853 when low doses of nitrogen fertilizer were used. The yield of various potato cultivars increased 1.2–1.4-fold as compared with uninoculated plants. Inoculation with Klebsiella mobilis decreased the content of nitrates in potato tubers 1–2-fold. The differences between plant nutrition of various potato cultivars were determined by a plant genotype. Inoculation with Klebsiella mobilis significantly increased the content of starch, nitrogen, phosphorus and potassium in potato tubers. The studied bacteria were able to colonize actively the potato tubers and roots. After joint inoculation Klebsiella mobilis decreased the survival of phytopathogenic Erwinia carotovora CIAM884 and protected the plants against soft-rot disease. It was concluded that Klebsiella mobilis strains CIAM880 and CIAM853 can be considered as associative nitrogen fixers (their acetylene-reducing activity was 329–407 nmol/ml per hour) and PGPR bacteria (all strains were able to produce indoleacetic acid) and used as biopreparations for increasing the productivity of potatoes.