Barley Inflorescence Architecture

Abstract

Cultivated barley, Hordeum vulgare ssp. vulgare, is the fourth most abundantly grown cereal in the world (www.fao.org/faostat) and is long associated with human civilisations. Although most barley grain grown today is destined for animal feed and malting, barley remains an important source of primary calories in many parts of the world. Increasing barley yield in the face of challenges posed by increasing world population and climate change is a major goal of current research efforts. Grain is the ultimate product of inflorescence development and maturation. As such, understanding the genetics underlying inflorescence architecture in barley and then learning how to apply this knowledge to manipulate inflorescence development are important steps towards improving yield. The barley reference genome sequence represents an invaluable resource to support the identification and functional characterization of genes controlling inflorescence architecture. Resolving the relationships between gene and inflorescence traits are critical to support breeding as well as to provide insight about fundamental questions in cereal developmental biology. In this chapter, we first provide an overview of inflorescence development in cereals, highlighting the transitions in meristem identity associated with species-specific architectures. From here, we describe the development of key morphological features associated with the barley spike, spikelet, floret and grain, while discussing the identification and functions of genes which regulate their development. We also discuss those genes whose variation contributed to architectural changes during domestication and those with yield potential. Lastly, we describe environmental control of inflorescence development, with special attention to flowering time and the agronomic environment.