The impact of nutrient supply on the yield, leaf area (LAI), relative chlorophyll content (SPAD) of two winter wheat varieties with different genotypes (GK Csillag, Mv Toldi) and the dynamics of these plant physiological parameters were examined in two different crop years (2013 = average, 2014 = favourable). In 2013, the yield of the different wheat varieties was between 1600–6200 kg ha-1 in a long-term experiment on chernozem soil, while the obtained yield was between 4400–8500 kg ha-1 in 2014, depending on genotype and the applied fertiliser dose. The impact of crop year was especially significant in the control treatment (1600–1700 kg ha-1 in 2013 and 4400–5400 kg ha-1 in 2014 without fertilisation). The yield increasing impact of fertilization was 4.0–4.5 t ha-1 in 2013 and 2.9–4.1 t ha-1 in 2014.

Leaf area was most significantly affected by crop year and fertilisation, while genotype had a less notable impact. The highest leaf area (LAImax) values were obtained at the BBCH 61–69 (silking) and BBCH 71–77 (milk stage) phenophases (0.8–2.8 m2 m-2 in 2013 and 0.9–7.9 mm-2 in 2014, depending on the applied fertiliser doses and varieties).

The relative chlorophyll content (SPAD) was less affected by crop year and genotype, but it was significantly influenced by fertilisation. The highest SPAD values were obtained at the BBCH 30–37 (shooting) and the BBCH 61–69 (silking) phenophases of winter wheat (SPADmax values were between 29.6–49.7 in 2013 and 43.2–62.2 in 2014).

Pearson’s correlation analysis showed a close and significant correlation between the yield the different wheat varieties and their LAI (0.681**–0.802**), as well as between yield and SPAD readings (0.767**–0.893**).

Keywords: winter wheat, yield, LAI, SPAD