THE CONTRIBUTIONS OF PLANT AND BACTERIA GENOTYPES IN THE GROWTH AND NITROGEN ACCUMULATION OF INOCULATED ALFALFA

The symbiotic efficiency of each of 30 alfalfa (16 Medicago sativa and 14 M. varia) cultivars inoculated with 7 Rhizobium meliloti strains w as studied in three field experiments. Two-factor analysis of variance of the obtained date demonstrated that the green mass yield and nitro gen accumulation depend on genotypes of both partners. The total contr ibution of plant and bacterial genotypes to the variation of green mas s yield increased from 0-17% in the first year of alfalfa growth to 40 -78% in the third year. The effect of the genotypic variability of the symbiotic partners was higher for N accumulation than for the green m ass. There was a negative correlation between plant mass and N accumul ation in the uninoculated plants with the relative (%) deviations of t hese parameters in the inoculated plants. In the experiments conducted in the Tashkent region the efficiency of the ''alfalfa - R. meliloti' ' symbiosis was higher than in the experiment conducted in the Tumen r egion.