Resistance of Winter Triticale Cultivars as a Key Determinant of Their Agricultural Use

Triticale (×Triticosecale) is an important cereal crop in Poland, valued for its high yield potential and tolerance to biotic and abiotic stresses; however, fungal diseases remain a major constraint to production. This study aimed to assess the resistance and yield performance of selected winter triticale cultivars under varying levels of chemical crop protection across diverse environmental conditions. Field experiments were conducted during the 2023/2024 and 2024/2025 growing seasons at 16 locations in Poland within the framework of Post-Registration Variety Testing (PRVT). Three cultivars (Medalion, Fanfaro, and SU Atletus) were evaluated under two agrotechnical levels differing in fertilization and protection intensity. Disease severity for powdery mildew, brown rust, and septoria leaf blotch was assessed using a 9-point scale, and yield data were analyzed using four-way ANOVA and multivariate methods. The results demonstrated significant effects of management intensity, cultivar, growing season, environment as well as interactions: management intensity × environment, cultivar × environment, growing season × environment, management intensity × growing season × environment and cultivar× growing season × environment were significant for all four traits of the study. Management intensity × cultivar as well as management intensity × cultivar × environment interactions were significant for powdery mildew, brown rust and septoria leaf blotch. Management intensity × growing season interaction was significant for powdery mildew and septoria leaf blotch. Management intensity × cultivar × growing season × environment interaction was significant for powdery mildew and brown rust. The cultivar × growing season interaction was significant only for brown rust and management intensity × cultivar × growing season interaction for septoria leaf blotch. Increased protection intensity generally reduced disease severity and improved yield. Medalion exhibited the highest yield stability, whereas SU Atletus achieved the highest yields under favorable conditions but with greater variability. Fanfaro showed intermediate performance. The findings highlight the importance of cultivar selection and management intensity in optimizing triticale production and support the role of PRVT in guiding agricultural practice under variable climatic conditions.