Forage sorghum in southern Manitoba

After a series of hot, dry years in the late 1980s a study was conducted to assess the suitability and yield stability of forage sorghum (Sorghum bicolor L. Moench.) in southern Manitoba. The effects of genotype and environment on DM yield of seven forage sorghum genotypes were evaluated (1990-1992) in six different environments. Genotype, environment and genotype x environment accounted for 3.9% (P < 0.0001), 84.8% (P < 0.0001) and 3.3% (P < 0.001) of the total variation in DM yield, respectively. The fact that environment accounted for most of the variability in DM yield and that relative rankings of varieties differed across environments indicated that yield was unstable. Forage sorghum produced acceptable DM yield only in years which were warmer (> 2700 CHU) than average (2200-2600 CHU) for southern Manitoba. Forage sorghum is not recommended for southern Manitoba unless the climate warms to where 2700 CHU are consistently accumulated during the growing season.