Reciprocal crosses were performed with barley (Hordeum vulgareL. cv. ‘Gateway’) and a virescens mutant derived from it. The results from F1and F2generations of the crosses showed that chlorophyll deficiency was governed by a single recessive gene. Quantitative analysis of pigment concentrations in normal and mutant shoots of F1and F2plants of the same age provided evidence for heterosis in chlorophyllasynthesis.