Helminthosporiosis caused by the fungus Drechslera sorokiniana (Sacc.) causes significant crop and quality losses to Triticum aestivum L. in agroecological conditions with extreme humidity. Increasing the resistance is considered the most cost-effective and sustainable approach to disease control. The aim of this study was to determine the genetic effects involved in the inheritance of resistance, using the ge-netic model of character reproduction in descendants of wheat. Generations F1, F2, BCP1 and BCP2, de-scended from the mutual crossing of the parents Basarabeanca / Moldova 30 and Moldova 30 / Moldova 3 (P1 and P2) were evaluated for the response of callus characters to the action of D. sorokiniana culture filtrate on the medium Murashige Skoog. Fungal metabolites have decreased the effects of gene actions and epistatic interactions, but also their variance. The phenomenon corresponds to the decrease of callus indices. A great importance for the heredity of the character of the surface of the callus manifested the epistatic effects of additive-dominant (ad) type. In the case of callus biomass comparable to the mean val-ues were the a actions, but also the ad and dd epistatic effects. The predominant involvement of epistatic effects indicates the need for resistance selections to helminthosporiosis in late generations of wheat.

The article presents data on the influence of water restrictions on the fungi Fusarium solani var. coeruleum. The considerable decrease of the share of the strain factor from 68.88% to 16.97% for F. solani, denotes the high survival capacity of the fungus in conditions of osmotic restrictions produced by the osmotic substance PEG, thus confirming the data from the literature. The spread of the mycelium in the form of plaque or film, the intensity of pigmentation, the presence of aerial mycelium show changes in the adaptation of the fungus to osmotic conditions, which have significantly affected the growth of F. solani.

The study established different reactions of the growth characters of the autumn common wheat seedlings to the treatment of seeds of genotypes Moldova 614, Moldova 66 and L Selania / Accent with the culture filtrates of the strains of Alternaria alternata, Drechslera sorokiniana and Fusarium solani. The 3 strains of the F. solani pathogen produced concomitant repression of root and stem in Moldova 614 and Moldova 66, but differentiated in L Selania / Accent, being identified as the most aggressive in this study. The highest sensitivity was recorded by L Selania / Accent in the case of the root under the action of Alternaria alternata strains.