Effect of main agronomy factors on the productivity and physical characteristics of common winter wheat (Triticum aestivum L.) grown under conventional and transitional-organic production

The aim of this study was to evaluate, based on the yield and the physical properties of grain, the response of five Tr. aestivum L. varieties developed at Dobrudzha Agricultural Institute grown under transition to organic production (TOP) and under conventional production (CP) during 2018 – 2020. Under TOP, decisive for productivity were the type of previous crop and the conditions for development in the specific year. The higher productivity of cultivars Kosara (3903.9 kg/ha), Rada and Kalina was advantageous under organic production. The CP of wheat exceeded by yield the TOP grown wheat with 2178.5 kg/ha (64.38 %), and in years with unfavorable conditions – with more than 80 %. Under CP, mineral fertilization was a yield-determining factor. The highest mean yield from the tested varieties was obtained under fertilization with N180P60K60 - 7189.8 kg/ha. Cultivar Rada was with the highest productivity under conventional growing (6143.9 kg/ha). Under both ways of production, cultivars Dragana and Pchelina had higher values of test weight. The previous crops pea and oil seed rape had favorable effect on the values of this parameter, while fertilization with N180P60K60 decreased them. Thousand kernel weight under both ways of production was highest in cultivar Kalina, followed by Dragana and Rada. In contrast to test weight, grain with highest 1000 kernel weight was obtained under the highest norm of mineral fertilization and after previous crop oilseed rape. The level of all tested correlations was considerably higher under the TOP in comparison to the CP for mass production of wheat.