Effect of seed test weight and planting depth on hard red winter wheat grain yield. From, Robertson, L.D. 1984. Kansas State University. Diseased seed, even though plump and of good test weight, with dark brown, black, pink or grayish colored kernels, should be avoided even though these are surface borne and may be helped considerably by seed treatment. Shriveled grayish or pink kernels may carry disease inside and should be removed in cleaning.
Loose smut is within the germ of the kernel.
A laboratory embryo test is needed to determine the percentage of loose smut infected barley kernels on all loose smut susceptible varieties. Yields are decreased in nearly direct proportion to the loose smut percentage. Seed with 5 percent loose smut will have 5 percent less yield than noninfected seed. Such a test is not available for wheat. Seed with over 2 percent loose smut is of questionable economic value for seed unless treated with an approved seed treatment.