**3. Results**

### *3.1. Concentration of Mineral Elements in Soil*

In order to determine soil conditions in both experimental fields analysis of a number of elements that occur in these environments was made (Table S1). For the most of 13 analyzed compounds significant differences between organic and conventional fields were found. Only for Co, concentration difference was not significant. In soil of conventional field, concentration of K, Mg, Cd, Cr, Cu, Ni, and Zn was higher than in soil of organic field. The highest differences were found for Zn (7-fold) and Cd (3-fold). On the other hand, in soil of organic field, concentration of Ca, Na, Si, B, and Mn was higher than in soil of conventional field.

### *3.2. Phenotypic Data and Fungal Diseases*

Wheat cultivars differed in heading and flowering time. In the conventional field, heading time was 29.7 days from 1 May, at a range 24.0 ('Smuga')—35.0 days ('Sukces') (Table S2). Flowering time was on average 31.6 days from 1 May, at a range 26.0 ('Smuga')—35.0 days ('Sukces', 'Boomer'). In the organic field, heading time was 28.0 days from 1 May, at a range 24.0 ('Smuga')—33.0 days ('Sukces'). Flowering time was on average 29.8 days from 1 May, at a range 26.0 ('Smuga', 'Ludwig')—35.0 days ('Sukces'). Heading and flowering time were significantly earlier in organic field than in conventional one (Table 3).


**Table 3.** Phenotypic characters, grain yield and Fusarium head blight (FHB) infection of 30 wheat cultivars grown in conventional and organic field.

Values within the same column followed by the different letters are significantly different at the level of probability < 0.01.

On average, plant height of wheat cultivars did not differ between organic and conventional fields (Table 3). In organic field plant height ranged between 73.7 cm ('Muszelka') and 114.3 cm ('Akteur') (Table S2). In conventional field, this parameter ranged between 76.3 cm ('Alcazar') and 118.7 cm ('Ludwig').

Fusarium head blight severity was low and average values for conventional and organic fields did not differ significantly (Table 3, Figure 1). In conventional field, FHB index range was from 0 to 4.4%. Cultivars 'Nateja' and 'Legenda' showed no symptoms of FHB and cultivars 'Kampana', 'Muszelka' and 'Slade' were the most infected (FHBi = 4.4%, 3.5%, and 2.1%, respectively) (Table S2). In organic field, FHB index range was from 0 to 3.2%. Cultivars 'Nateja' and 'Mewa' showed no symptoms of FHB and cultivars 'Slade', 'Kampana', 'Turkis' and 'Belenus' were the most infected (FHBi = 3.2%, 2.3%, 1.8%, and 1.8%, respectively). FHB indexes for conventional and organic fields correlated significantly (*r* = 0.776 at *p* < 0.001).

**Figure 1.** FHB symptoms on heads of wheat grown in organic field. Clockwise from top left: 'Figura', 'Muszelka', 'Kampna', 'Slade'. Wheat at early milk growth stage (BBCH 73).

Heading and flowering time were not correlated with FHB severity. In both fields plant height significantly negatively correlated with FHB indexes (*r* = −0.519 for organic field and *r* = −0.589 for conventional field; at *p* < 0.001).

Symptoms of leaf diseases in both experimental plots were observed starting from half of May, when yellow rust was detected. Seventeen cultivars were fully resistant to yellow rust and showed no symptoms of disease (Table S3). On average yellow rust severity was slightly higher in conventional field; however, difference with organic field was not significant. Leaf rust severity was low. On average, it was 0.7% in organic field and 1.0% in conventional one. (Table S3). Symptoms of Septoria tritici blotch were observed on most (28) cultivars in conventional field and on 17 cultivars in organic field. Symptoms of Stagonospora nodorum blotch were observed on 12 cultivars in conventional field and on 23 cultivars in organic field. Tan spot was observed only in organic field with average severity 2.0%. This disease affected fourteen cultivars.

Grain yield per plot was similar for both field and do not differ statistically significantly (Table 3). In organic field grain yield ranged between 3.1 kg ('Nateja') and 6.7 kg ('Jenga') (Table S1). In conventional field, this parameter ranged between 2.9 kg ('Nateja') and 6.6 kg ('Boomer'). In both field grain yield was significantly negatively correlated with yellow rust severity (*r* = −0.517 for organic field and *r* = 0.647 for conventional field; at *p* < 0.001) and not correlated with FHB indexes.
