Phenological growth stages of Brachypodium distachyon: codification and description

Brachypodium distachyon is being used as a new model monocotyledon for grass crop research and bioenergy grass biotechnology. With the recent completion of the full genome sequencing project, one of the next major challenges is to determine the functional activities of many genes. In an attempt to aid the rapid determination of gene function in crop plants, a high throughput phenotypic analysis system has been established through phenological analyses of a series of defined growth stages. The codification follows the BBCH (Biologische Bundesantalt, Bundessortenamt and CHemische Industrie) scale, a numerical system that differentiates between principal and secondary growth stages from seed germination to flower head emergence and seed ripening. We present here analyses of the phenological development stages of B. distachyon to illustrate a methodological framework that can be used to identify and interpret phenotypic differences derived from genetic variations and environmental stress responses in this plant species. This scale may greatly contribute to the B. distachyon research in the future, particularly to functional determination of genes that mediate biomass productivity. It may also serve as a suitable tool for defining the growth stages of other grass species.