The peculiarities of photosynthetic system functioning in barley alloplasmic lines were investigated by PAM fluorimetry. The substitution of nuclear genome was shown to affect differently several photosynthetic parameters. The importance of the balance between nuclear and organelle barley genetic systems for the photosystem II functioning was demonstrated.

55 cultivar genotypes were identified on the genetic system Vrd, controlling winter wheat vernalization duration differences. The frequency of the genotypes Vrd1Vrd1vrd2vrd2 scored 50,9 % (28 samples). The differences between the frequencies of the genotypes vrd1vrd1Vrd2Vrd2 (9 samples, 16,4 %), Vrd1Vrd1Vrd2Vrd2 (10 samples, 18,2 %) and vrd1vrd1vrd2vrd2 (6 samples, 10,9 %) were not significant.

Double inoculation with arbuscular mycorhizal fungi and nodule bacteria was shown to increase seed productivity and plant dry weight in most of pea genotypes studied. Sometimes it can exceed the effect of mineral fertilizers.Seed productivity and plant dry weight were chosen as main criteria for evaluation of symbiosis effectiveness of legume crops. Expediency of legume breeding to improve symbiotic potential of legume varieties was proven and the genotypes to be used in such breeding programs were identified.