Multifactorial wheat response under Fusarium culmorum, herbicidal, fungicidal and biostimulator treatments on the biochemical and mycotoxins status of wheat

A large-scale study under controlled conditions was conducted to estimate the influence of diversified level of biotic: Fusarium culmorum and abiotic factors: herbicide (H; sulfosulfuron), fungicides (F1; cyproconazole + propiconazole), (F2; spiroxamine + tebuconazole + triadimenol) and humic biostimulator (B) on the profile of biochemical compounds (6 groups) and mycotoxins (11) in wheat grain. The following experiments were conducted: I: wheat inoculation with F. culmorum spore suspension (OD600 = 0.3; 0.7; 1.3), II: H, III: H+½F1+½F2, IV: H + F1 + F2, V: H + B, VI: H + F1 + F2 + B and VII: B. Multifactorial wheat response to biotic/abiotic stress factors was noted, manifesting in the highest reduction of total soluble carbohydrates (28%; IV) and proteins (34%, VII) related to abiotic factors. The lowest starch concentration was determined in Exp. I (600.54 µg g−1 dm), while the highest was found in control (794 µg g−1 dm). Furthermore, the maximum level of amino acids was observed in Exp II, and of phenolic compounds in Exp. I (894.59 and 933.93 µg g−1 dm, respectively). For the first time, acid phosphatase activity was determined in wheat grain under sulfonylurea, morpholine, triazole and humic biostimulator protection, indicating biostimulator contribution to elevated absorption of assimilable phosphorous forms and improvement of crop nutrition. Total mycotoxins: 3-AcDON, 15-AcDON, DON, NIV were the highest in inoculated wheat (Exp. I, 2063.9 µg kg−1). The most effective protection and the lowest concentration of mycotoxins was achieved in Exp. VI (155.3 µg kg−1, 67% reduction compared to control). Our study indicated that chemical treatments enriched by humic biostimulator could be implemented in the integrated program of wheat protection in agricultural practice.