Thermal time – concepts and utility

Wheat was among the last of the major crops to be transformed (in 1992), and transformation is still difficult, with a lower efficiency than that for maize and rice. However, the recent development of Agrobacterium‐based systems is set to improve the precision of the process, while new methods of selection, removal of unnecessary DNA sequences, gene targeting and in vivo mutagenesis will make the process cleaner and more acceptable to regulatory authorities and consumers. Our current work is focussed on using transformation to understand and manipulate aspects of grain processing quality, notably dough strength and texture for milling. However, it is clear that a major priority for future work will be to improve nutritional quality, including vitamin and mineral contents for the developing world and starch digestibility and dietary fibre content and composition for developed countries.