ISOZYME STUDIES IN HYBRID BARLEY

Six isozyme systems were studied in hybrid barley to investigate the types of gene action that might be responsible for heterosis in grain yield. Zymotypes of hybrid plants contained the sum of parental bands for peroxidase, α-amylase, and esterase, the three systems that varied in the material. Genetic studies of esterase and α-amylase isozymes indicated that band differences between parents were completely additive in the hybrid. The gene action observed in the hybrids was attributed to a combination of epistasis and overdominance. The maternal esterase pattern in 20% of the plants in one of the hybrids suggested that the balanced tertiary trisomic method is not fully efficient for inducing complete male sterility.