In wheat (
Triticum aestivum
L.) several studies have
reported genetic gain for grain yield over the years.
However, studies on wheat bread-making quality are
scarce. Our objective was to estimate the progress due to
genetic and environmental components in wheat breadmaking
quality parameters. In addition, we aimed to
examine trends in historical cultivars and associate traits
performance with geographical parameters. We used data
from multi-environment trials (MET) represented by
eight years (2005-2012) and 458 genotypes, including
lines and commercial cultivars (controls). We determined
the genetic progress by the contrasts between genotypes
assessed in each biennium, excluding the year effect. This
effect is previously estimated by existing variation among
common genotypes. Genotype replacement rate was 52%
and reflects the dynamism of the breeding program to
develop better genotypes in terms of bread-making quality.
The genetic progress estimated for gluten strength (W)
was 1.30% yr
-1. The progress in W demonstrated to be
partly counterbalanced by the environmental effect
(-0.78% yr
-1). We observed disequilibrium tendency
in relationship between tenacity and extensibility
(P/L ratio) as a consequence of searching for lines with
high W. Analysis showed that P/L ratio can be reduced
in responses to the increase in latitude of the location.
Environmental and genetic effects on the traits variation
were discussed.
