STABILITY AND ADAPTABILITY OF YIELD AND YIELD RELATED TRAITS IN BULGARIAN TRITICALE (×Triticosecale Wittm.) CULTIVARS IN DROUGHT CONDITIONS

To determine the adaptability and stability of yield and its related traits during drought conditions in triticale, eleven contemporary Bulgarian cultivars were studied according to the indices yield, number of productive tillers, 1000 kernel weight and number of grains in spike, applying four parameters: regression coefficient and deviation from regression, ecovalence and stability variance of Shukla. Drought had a significant effect on the yield related traits, which differed considerably according to the different parameters of stability. The best combination of stability and adaptability according to number of productive tillers and 1000 kernel weight was observed in Bumerang and Doni 52. The parameter number of grains in spike behaved in a rather complex manner under conditions of drought and the separate stability parameters related to contradictory results. The widest adaptability according to this parameter was observed in cultivars Rakita, Lasko and Respekt. The stability and adaptability parameters of the separate yield traits was not functionally related to the same parameters of yield, which determined the investigated cultivars as developed according to a complex of traits and being suitable for growing under variable environments.