Growth and Yield of Four Cultivars of Sour Cherries (Prunus cerasus L.) Grown in Organic and Conventional Systems

In recent years, Polish producers have been increasingly interested in organic fruit production. In this cultivation system, it is very important to choose cultivars that are less susceptible to diseases and pests. In research conducted in the years 2009–2019 in central Poland, the suitability of four sour cherry cultivars (‘Kelleris 16’, ‘Oblacinska’, ‘Debreceni Bötermö’, ‘Pandy 103’) for organic cultivation was assessed. The trees grew in two separate experimental quarters: conventional and organic, about 1 km apart. It was proved that organic sour cherry cultivation is possible, but there are many challenges. In the organic cultivation system, trees were more sensitive to low temperatures and grew and yielded less than those grown using conventional methods. The weaker growth and lower yields were mainly due to the ineffective protection against cherry leaf spot and brown rot. The fruit quality was closely dependent on the weather conditions. The fruit harvested in the organic orchard had a lower weight but tended to be firmer than that harvested in the conventional one. The smallest, but most abundant in soluble solids, were the fruits of the ‘Oblacinska’ cultivar. Unfortunately, they were infested by larvae of cherry fruit flies. Occasionally, the pest larvae lived in organic sour cherries of the ‘Pandy 103’ and ‘Debreceni Bötermö’ cultivars. In years with high rainfall, 20 to 35% of the fruit in the organic quarter was affected by fungal diseases.