Cold plasmais a potentially new method of controlling diseases caused by fungal pathogens. In this investigation the effect of treatment with cold plasma of durum wheat seeds contaminated with Fusarium graminearum on the germination and growth of plants was studied. Plants of 6 durum wheat varieties were pre-contaminated with spore suspension of Fusarium graminearum. The harvested seeds were treated with cold plasma in 4 variants: 1– direct treatment with Argon plasma torch sustained by travelling electromagnetic wave; 2 – treatment with the same plasma torch of seeds in 20 ml distilled water; 3 – underwater diaphragm discharge treatment in the container with applied voltage of 15 kV electrode, denoted by “+”; 4 – underwater diaphragm discharge treatment in the container with grounded electrode, denoted by “–“. Two control variants were used – dry not treated contaminated seeds and wet not treated contaminated seeds. After the treatment the seeds were placed in petri dishes for germination. Sprouted seeds were planted in pots with soil mixture and cultivated to maturity in green house conditions in Field Crops Institute –Chirpan, Bulgaria in 2017/2018 year. The effect of the treatment on the following traits were studied: germination rate, days to heading, plant high, parameters of chlorophyll fluorescence during the grain filling, spike length, kernel number per spike, kernel weight per spike, TKW and obtained ill (Fusarium graminearum) and healthy seeds. The results received were processed statistically via two-way ANOVA and Duncan’s multiple range test. The analysis of variance reveals that the genotype, treatment with cold plasma and the interactions between them have a statistically significant effect on the variation of the germination rate. The best germination rate (means from all genotypes) was obtained by treatment with cold plasma variant 1 - direct treatment with Argon plasma torch sustained by travelling electromagnetic wave and variant 3 - underwater diaphragm discharge treatment in the container with applied voltage of 15 kV electrode, denoted by “+”. After the germination the number of seeds contaminated with Fusarium graminearum was the lowest after variant 4 in the treatment of three of the studied varieties. Stimulating effect of the cold plasma treatment on the plant growth was found in 4 genotypes. Varieties Elbrus, Progres, Deni and Zvezdica were with higher PH during the grain filling. The results from the influence of cold plasma on the other studied traits will be processed after the plant maturation and will be included in the final version of the paper.

Acknowledgments: This work was supported by Bulgarian National Science Fund under Grant No DH08/8, 2016.