Influence of nitrogen application on grain yield and end use quality in segregating generations of bread wheat (Triticum aestivum L)
Keywords:
Bread wheat, segregating populations, nitrogen and protein electrophoresis.Abstract
Variation in bread making quality of wheat (Triticum aestivum L ) is a major consideration for suppliers and
bakers. Grain protein concentration, protein quality, ash content and carbohydrates are major quality attributes
of bread wheat. Breeders and their cereal chemist colleagues use predictors of these end use quality factors in
the early generations to develop improved cultivars. Six populations of bread wheat derived from a previous
diallel experiment were evaluated under three rates of nitrogen fertilizer for grain yield and end use quality.
Increasing nitrogen (N) rates from low (40 kg fad-1. N) to high (120 kg fad-1. N) had an accelerating significant
effect on grain yield and quality in F2 and F3 generations. Desirable quality types along with high grain yield
were defined within the C3, C4 and C6 populations. The population C6 exhibited the highest flour protein (13.8%)
and the lowest flour ash (0.42%) as well as good grain yield as compared with the check variety and other
populations. In F3 populations, 1000-kernel weight was an effective selection criterion for grain yield in pop. C3,
C4 and C6 but it caused reduction in flour protein in pop. C1. Grain protein concentration showed an increasing
trend in F3 generation, confirming the positive relationship with grain yield. The expected response to selection
of F3 populations under high N level were 8.81% for grain yield, 8.0% for flour protein 5.74% for gluten and 4.98%
for carbohydrates. The SDS-PAGE of grain storage proteins was performed in order to analyze molecular weight
of gluten subunits (GS) and investigate genetic diversity among the selected populations. The population C6
exhibited the highest unique bands (5 from 7 bands) under high N level and followed by the population C4. The
high N level generally increased total high-molecular weight-GS content in wheat grain, although different
patterns of response to N rate were observed between populations.
