Variation, across environments within the UK, in grain protein and grain hardness, in wheat varieties of differing distilling quality

Twelve soft-milling wheat varieties were grown, over a total of 12 environments, trials being sown in three locations, in two seasons, both with and without nitrogen fertiliser (N) application. Grain protein and hardness levels were assessed on all samples and initial analysis showed highly significant effects of variety, site, season and N-rate on both characters. The environments differed widely for mean protein and hardness levels and the response of the individual varieties was assessed by linear regression of their protein and hardness values on the mean value of all twelve varieties, in each environment. For protein, there were very strong correlations between the environment means and the means of the individual varieties, but there were also slight differences in stability across environments, with varieties like Claire showing a tendency to accumulate more grain protein at sites characterised by higher protein levels. At sites with highest grain hardness, Ambrosia and Kipling, which both carry the 1B/1R translocation, had much harder grain than the other varieties. Correlations, across varieties, between grain protein and hardness were significant in only some environments. It was concluded that grain hardness could be a useful additional parameter for assessing both breeding lines and distillery intake samples, while further research should consider variation in grain texture and its genetic control.

► We studied variety, site, year and fertiliser effects on wheat protein and hardness.
► Varieties differed in stability across environments for these traits.
► Hardness was not well related to protein content at some sites.
► The 1B/1R translocation appeared to strongly affect grain hardness.
► NIR hardness measurements can assist in selecting wheat samples for distilling.