GRAIN YIELD AND QUALITY OF SPRING WHEAT VARIETIES UNDER ORGANIC FARMING SYSTEM

14 spring varieties are registered in Latvian Catalogue of Plant Varieties but only one (cv. Uffo) is approved for organic farming system. The rest of varieties are highly intensive and more suitable for conventional farming. The aim of this research was to evaluate and compare grain yield and quality of 20 spring wheat varieties under organic farming system. The results of investigations showed that the average yield level of varieties was not significantly (p<0.05) higher than that of the standard variety 'Arabella' (4.39 t ha(-1)). Spring wheat varieties 'Quintus' (4.89 t ha(-1)), 'Cornetto' (4.69 t ha(-1)), 'Licamero' (4.57 t ha(-1)) and 'Sonett' (4.54 t ha(-1)) showed the best results. Grain yield of varieties 'Robijs' and 'Uffo' had the standard level (4.25 and 4.05 t ha(-1), respectively), but the varieties were characterized by yield stability. Varieties 'Hamlet', 'Nawra' and 'Cornetto' showed the highest TGW. Spring wheat varieties 'Taifun', 'Tybald' and 'Mooni' had the best grain quality (protein, gluten content and sedimentation value), but the variety 'Hamlet' had the highest volume weight.