Comparative genetic approaches to the identification of flowering time genes in temperate cereals

The timing of flowering during the year is an important adaptive character which impacts yield and quality in crop plants. The genetic basis of flowering time control is best understood in the model dicot arabidopsis (Arabidopsis thaliana [L.] Heynh.) and results from this system are briefly summarized. Recent results from rice are discussed in relation to arabidopsis, particularly in relation to conserved genes regulating flowering by photoperiod. How these results might benefit studies of temperate cereals is then considered. Genetic analysis of photoperiod and vernalization response in temperate cereals is summarized in relation to recent data pointing to greater evolutionary conservation of photoperiod response than vernalization response. The implications of these results for identifying additional genes in cereals are discussed. The aim of gene identification is to provide a better understanding of how plant development is controlled by environmental cues such as day length and temperature and to allow researchers to determine how many alleles of each gene are available. This information could be combined with physiologically-based whole plant growth models to provide an improved description of crop development. Improved understanding of the control of flowering would assist plant breeders in the selection of varieties with enhanced adaptation to existing environments or to new environments arising from climate change. (C) 2004 Elsevier B.V. All rights reserved.