Molecular genetic studies on processing traits of wheat flour

摘要

Advances in the genetic mapping of wheat, the molecular interpretationof flour processing traits and large-scale sequencing of genes expressed inendosperm tissue are currently converging to define the genes thatunder-pin key quality traits. In order to achieve this, accurate definitions ofa phenotype such as dough extensibility are essential and in this paper amolecular/genetic analysis of this trait is presented. Studies carried out onthe small-scale Mixograph have provided the data to indicate that themixing action in this system develops the dough through multipleelongate-rupture-relax cycles of the flour/water mixture. The measurementcan be used to define a variable we refer to as `M-extensibility', a measurevery closely related to the traditional extensibility measurement and mostlikely a sub-component of this `classical' assessment. Analyses based onmolecular genetic maps have shown that both LMW and HMW gluteninloci most likely account for significant variation in M-extensibility. Inaddition, it is evident that genes on chromosome 2 also contribute andwork is in progress to characterize these genes. The possibility will bediscussed that new seed storage protein genes being discovered from theanalysis of 5000 cDNA's from endosperm tissue (8–12 days post anthesis)have a role to play in M-extensibility.