Ontogenic Changes in Leaf Pigments, Total Soluble Protein and Rubisco in Two Barley Varieties in Relation to Yield

Two barley (Hordeum vulgare L.) forage varieties – Hemus and Karnobat, with high and low Rubisco content in the fully expanded first leaves (Metodiev and Demirevska-Kepova, 1992), were compared in pot vegetation experiments in respect of yield. Changes in the content of leaf pigments, the levels of total soluble and Rubisco immunoreactive protein were followed during six phenophases: 3rd leaf, tillering, stem extension, heading, anthesis and milk ripeness. The results show maintenance of high level of photosynthetic components in the phases critical for grain filling regardless of the differences observed in the primary leaves. Thus, the use of Rubisco as an early selection criterion for improved yield is dubious. The question, whether Rubisco content in leaves during the grain-filling period might be a useful marker for productivity, remains open and needs further investigations.