BGS 19, Non-blue aleurone xenia 2, blx2

Blue aleurone 1= Bl1, a second factor for blue aleurone (6).
Non-blue aleurone 2 = bl2 (9).

Monofactorial recessive when complementary dominant alleles are present at the Blx1, Blx3, Blx4, and Blx5 loci 2, 5, 8).
Located in chromosome 7HL (2, 5, 8); blx2.b is about 3.9 cM distal from the msg10.ay (male sterile genetic 10) gene (5); blx2.b is approximately 9.9 cM distal from the nud1 (naked caryopsis 1) locus (8); blx2.b is approximately 12.1 cM from the nud1 locus (5); blx2.b is about 29.9 cM from the fch12.b (chlorina seedling 12) gene (10); blx2.b is weakly linked to blx5.e (10).

Blue aleurone color is due to anthocyanin pigments (7), which occur as lumps inside many aleurone granules in some or all aleurone cells (2). Variation in blue color expression from dark blue to an off-white is caused by environmental factors and modifying genes (2, 5, 10). Aleurone color is best observed in well-filled grain that is magnified to show individual aleurone cells, after more superficial tissues have been peeled off (6). Some heterozygous plants at the Blx2 locus showed little or no male transmission of the dominant allele (4, 5, 11).

Non-blue aleurone (blx2.b) is recessive allele that occurs more frequently in six-rowed cultivars of Oriental origin (5, 8).

blx2.b(GSHO 209) in Nepal (PI 12709) (5, 8).

blx2.b (GSHO 209) in Nepal (PI 12709); the recessive allele, blx2.b, is present in Bowman (PI 483237, NGB 22812) in combination with the recessive allele (ant1.b, rst1.b) at the anthocyanin-less 1 locus (1, 3).

1. Druka, A., J. Franckowiak, U. Lundqvist, N. Bonar, J. Alexander, K. Houston, S. Radovic, F. Shahinnia, V. Vendramin, M. Morgante, N. Stein, and R. Waugh. 2011. Genetic dissection of barley morphology and development. Plant Physiol. 155:617-627.
2. Finch, R.A., and E. Simpson. 1978. New colours and complementary colour genes in barley. Z. Pflanzenzücht. 81:40-53.
3. Franckowiak, J.D. (Unpublished).
4. Jain, S. K. 1970. Gene pools, variation and selection. p. 422-429. In R.A. Nilan (ed.) Barley Genetics II. Proc. Second Int. Barley Genet. Symp, Pullman, WA, 1969. Washington State Univ. Press, Pullman.
5. Kushnak, G.D. 1974. Utilizing linkages of genetic male sterile and aleurone color genes in hybrid barley (Hordeum vulgare L.) systems. Ph.D. Thesis. Montana State Univ., Bozeman.
6. Mullick, D.B., and V.C. Brink. 1970. A method for exposing aleurone tissue of barley for color classification. Can. J. Plant Sci. 50:551-558.
7. Mullick, D.B., D.G. Faris, V.C. Brink, and R.M. Acheson. 1958. Anthocyanins and anthocyanidins of the barley pericarp and aleurone tissues. Can. J. Plant Sci. 38:445-456.
8. Myler, J.L., and E.H. Stanford. 1942. Color inheritance in barley. J. Am. Soc. Agron. 34:427-436.
9. Robertson, D.W., G.A. Wiebe, and R.G. Shands. 1947. A summary of linkage studies in barley: Supplement I, 1940-1946. J. Am. Soc. Agron. 39:464-473.
10. Shim, J.W., and S.J. Suh. 1987. Linkage relationship of blue aleurone genes (Bl's) in barley. p. 213-217. In S. Yasuda and T. Konishi (eds.) Barley Genetics V. Proc. Fifth Int. Barley Genet. Symp., Okayama. 1986. Sanyo Press Co., Okayama.
11. Wiebe, G.A. 1972. Blue aleurone caused by complementary genes in very close translinkage. Barley Genet. Newsl. 2:109.
12. Wiebe, G.A., and D.A. Reid 1961. Classification of Barley Varieties Grown in the United States and Canada in 1958. U. S. Dept. Agr. Tech, Bul. 1224. 234 pp.

T.E. Haus. 1975. Barley Genet. Newsl. 5:100.

R.A. Finch. 1978. Barley Genet. Newsl. 8:164.
J.D. Franckowiak and R.A. Finch. 1997. Barley Genet. Newsl. 26:65.
J.D. Franckowiak. 2018. Barley Genet. Newsl. 48:63-64