Plum cultivars Zlatka and Pozna Plava (Prunus domestica L.) bred at the Fruit Research Institute in Čačak

This study was carried out to compare the most relevant biological characteristics and field resistance to economically important diseases of the new (Zlatka and Pozna Plava) and standard plum cultivars (Čačanska Lepotica and Čačanska Rodna) in the Region of Čačak. The experimental area climate belongs to the temperate type. The mean annual air temperature during the experimental period was 12.65°C, and humidity was 80.4%. The average annual rainfall was 571.2 mm. The ripening time of the cv. Zlatka occurred between August 3-23, while the cv. Pozna Plava ripened between August 26-September 25. Compared to cv. Čačanska Lepotica, cv. Zlatka had a significantly lower mean fruit weight, reducing sugars and total acids content, but a significantly higher proportion of flesh, yield and sucrose content. Compared to cv. Čačanska Rodna as the standard cultivar, cv. Pozna Plava had a significantly higher mean individual fruit weight and total acids content, but also a significantly lower orchard yield and sweetness measured as fruit soluble solids, total sugars, reducing sugars and sucrose content. As regards the field resistance to economically important diseases such as red leaf spot, rust, fruit root, pockets plum disease and sharka disease, both new cultivars demonstrated better results than the reference cultivars.