A quality assurance strategy for wheat (Triticum aestivum L.) where growth environment predominates

The variation in the processing quality of South African winter wheat cultivars over growth environments is detrimental to its market value. Variation in protein content has previously been identified as a primary contributor to this variation and should therefore be considered in the interpretation of quality data presented during the cultivar release procedure. The aim of the study was to analyse such effects on the interpretation of quality data of advanced wheat lines. Our results indicated a distinctive segregation between entries having higher (≥10%) and lower (<10%) flour protein contents for the three critical phases of commercial processing. The incorporation of a range of localities where both protein levels are sufficiently represented, appeared to be of more importance than the number of harvest seasons over which the entry is evaluated. Finally, multivariate statistical techniques were used to compute user-friendly models for the objective characterisation of variation in milling and rheological quality of wheat lines. The interpretation of genotypic and environmentally related variation was also improved through graphical presentations. The application of these models within the context of deregulation of the wheat industry, is also demonstrated.