engleski

Biodiversity and selection of indigenous rhizobia associated with pea (Pisum sativum L.) in soils of western Herzegovina

An essential element of agricultural sustainability is the effective management of nitrogen in the environment. This usually involves at least some use of biologically fixed nitrogen because N from this source is used directly by the plant, and therefore is less susceptible to volatilization, denitrification and leaching. Despite that, legume inoculation with selected, high-quality rhizobial strains has not become usual procedure in the production of these important crops in Herzegovina. Selection of the most suitable strains represent one of the main presumptions for successful inoculation due to the fact that rhizobial strains strongly differ in their effectiveness, competitiveness and compatibility (1, 2). However, the presence of adapted and competitive indigenous rhizobia in soil can reduce the inoculation response even with the highly efficient commercial strains. Thus the composition and characteristics of rhizobial field populations are of great agricultural importance in the legume production (3, 4). Pea (Pisum sativum L.) is widely cultivated plant in the area of western Herzegovina due to their favorable nutrient composition and other health benefits that were recognized more recently. The main objective of the present study was to get insight into actual composition of indigenous population of pea rhizobia and to characterize indigenous strains isolated from different soils in western Herzegovina. The indigenous rhizobial strains were isolated from pea nodules collected from different field sites in western Herzegovina. RAPD and ERIC-PCR methods were used for strain identification and evaluation of genetic diversity among indigenous rhizobia. In order to determine the nodulation ability and symbiotic efficiency of indigenous R. leguminosarum strains, two-year field trials were set up at different locations near Mostar. At various locations in western Herzegovina, the presence of indigenous R. leguminosarum strains was determined as well as the considerable level of genetic diversity within natural populations. In comparison with reference strain and non-inoculated control, most of indigenous rhizobial strains showed significantly higher nodulation ability and symbiotic efficiency. The application of two indigenous strains (V1 and V13) isolated from soils in the area of Mostar and Široki Brijeg, resulted in the most abundant nodulation and the highest symbiotic efficiency. These are the first studies of indigenous pea rhizobia in Herzegovina. The obtained data clearly confirm the importance of rhizobial strain selection and can contribute to a better understanding of rhizobial ecology.

nitrogen fixation; indigenous rhizobia; genetic diversity; R. leguminosarum

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