Abstract
Wheat grown in paddy fields has lower bread-making quality than wheat grown in upland fields because of lower grain protein content. Nitrogen topdressing at flowering increases flour protein content. Here, we investigated the effects of the nitrogen topdressing at flowering on the bread-making quality of wheat grown in a paddy field. Nitrogen topdressing at 8 g m-2 at flowering raised the flour protein content to 13% which is as high as that in wheat grown in the upland field. However, the valorimeter value (VV) on the farinogram, an indicator of bread-making quality, was smaller in wheat grown in a paddy field than that grown in the upland field. The protein content of the flour was as high as 13%, detention time (DT) on the farinogram was shorter, water absorption on the farinogram was larger, and compression of bread was smaller in wheat grown in the paddy field than in wheat grown in the upland field. The bread made from wheat grown in the paddy field was softer than that made from wheat grown in the upland field. The ratio of sodium dodecyl sulfate (SDS)-soluble extractable monometric proteins (EMP) to SDS-insoluble unextractable polymeric proteins (UPP) in the flour was significantly lower in wheat grown in the paddy field than in wheat grown in the upland field. Wheat grown in the paddy field ranked B or C owing to its high ash content and low volume weight even with nitrogen topdressing of 8 g m-2 at flowering. On the other hand, wheat grown in the upland field ranked A in all test groups.
