The barley grain has a central furrow. Genetic variation is found for the presence or absence of hairs within the central furrow.
This triat is scored during national varietal registration trials, as described by UPOV guidelines: "Grain: ventral furrow - presence of hairs" (UPOV character 26. Scores: 1 = absent; 5 = very fine hairs/sharkskin; 9 = present).
see http://www.upov.int/test_guidelines/en/list.jsp