Genotype and environment effects on the contents of vitamins B1, B2, B3, and B6 in wheat grain.

The total contents of thiamine (vitamin B1), riboflavin (B2), and pyridoxine (B6) and the bioavailable forms of niacin (B3) were determined on wholemeal flours of 24 winter wheat varieties grown on four sites (United Kingdom, Poland, France, and Hungary) in 2007 and of two spring varieties grown on the same sites with the exception of Poland. The contents of vitamins B1 (5.53-13.55 μg/g dw), B2 (0.77-1.40 μg/g dw), and B6 (1.27-2.97 μg/g dw) were within the ranges reported previously, while the content of bioavailable vitamin B3 (0.16-1.74 μg/g dw) was about 10-15% of the total contents of vitamin B3 reported in previous studies. Strong correlations were observed between the contents of vitamins B1, B3, and B6, and partitioning of the variance in the contents of these three B vitamins showed that between 48 and 70% was accounted for by the environment. By contrast, the content of vitamin B2 was not correlated with the contents of other B vitamins, and 73% of the variance was ascribed to the error term, which suggests that this trait may be influenced by genotype × environment interactions. Whereas the contents of vitamins B1, B3, and B6 were correlated positively with the mean temperature from heading to harvest (r > 0.8), the content of vitamin B2 was positively correlated with precipitation during the 3 months prior to heading. These results are discussed in relation to the development of new wheat varieties with enhanced health benefits.