The number of tillers (side shoots) and the number of seeds per spike has been strongly modified during the domestication of cereals such as barley and wheat. Until now, breeding for variable tiller number is used in cultivated barley to optimize yield. This strategy, however, is hampered by negative correlations between tiller number and other important yield components such as number of seeds per spike and seed weight. We thus want to decipher the genetic and molecular correlation between shoot and spike architecture. We utilize high-tillering mutants to identify genes controlling tiller number and study their role in the spike development and consequently their impact on yield.
Left: Shoot architecture of a high-tillering mutant in comparison to a barley cultivar with a moderate number of side shoots. Right: Scanning electron microscopy image of a developing inflorescence in a barley high-tillering mutant. Instead of spikelet primordia, the mutant produces branch meristems (orange) resulting in a branched spike.
Head of Institute
High ambient temperature is one of the major abiotic stresses that limits productivity of temperate cereals. High ambient temperature impairs inflorescence development and floret fertility, and is thus a major cause of yield losses in barley. However, the mechanisms that underpin the temperature-responsive inflorescence development are not fully understood. We identify natural genetic variants in adapted barley germplasm that control the activity of the inflorescence meristem and thus the rate and duration of spikelet and floret primordium initiation under high temperature. We are interested in how these genetic variants and temperature impact on the level and distribution of metabolites and hormones in the plant and how this in turn impacts on meristem development and activity which ultimately control growth, development and plant architecture.
High ambient temperature decreases the size and activity of the inflorescence meristem and the number of spikelets induced (image: T. Lan).