Molecular genetic studies on processing traits of wheat flour

Advances in the genetic mapping of wheat, the molecular interpretation of f lour processing traits and large-scale sequencing of genes expressed in end osperm tissue are currently converging to define the genes that under-pin k ey quality traits. In order to achieve this, accurate definitions of a phen otype such as dough extensibility are essential and in this paper a molecul ar/genetic analysis of this trait is presented. Studies carried out on the small-scale Mixograph have provided the data to indicate that the mixing ac tion in this system develops the dough through multiple elongate-rupture-re lax cycles of the flour/water mixture. The measurement can be used to defin e a variable we refer to as 'M-extensibility', a measure very closely relat ed to the traditional extensibility measurement and most likely a sub-compo nent of this 'classical' assessment. Analyses based on molecular genetic ma ps have shown that both LMW and HMW glutenin loci most likely account for s ignificant variation in M-extensibility. In addition, it is evident that ge nes on chromosome 2 also contribute and work is in progress to characterize these genes. The possibility will be discussed that new seed storage prote in genes being discovered from the analysis of 5000 cDNA's from endosperm t issue (8-12 days post anthesis) have a role to play in M-extensibility.