Gains in yield and stability were analysed using grain yield data from the 8th to the 14th International Triticale Yield Nursery (ITYN) and differences in adaptation between complete and substituted triticales (X Triticosecale Wittmack) were examined. A trend of improving yield and adaptation was observed. As highly significant genotype x site interaction each year was not adequately described using regression analysis, yield stability was examined by ranking genotypes within sites and summarizing scores for individual genotypes across sites. Cluster analysis was used to study the relationships among sites and among genotypes. There was little evidence of sites grouping on a geographical basis. Grouping of genotypes showed a tendency for complete and substituted triticales to perform differently, suggesting that diversity for adaptation is maximized by utilizing both types in breeding.
Progress for grain yield is compared with more spectacular gains in test weight and reasons for the different rates of improvement are postulated.
Abbreviations
: CIMMYT -International Maize & Wheat Improvement Centre; ITYN -International Triticale Yield Nursery * contribution from CIMMYT/Agriculture Canada (No. R-002