BGS 15, Non-blue aleurone xenia 1, blx1

Blue aleurone = Bl (1).
Complementary factors for blue vs. white aleurone = Bl1 and bl1 (4).
Complementary factors for blue vs. white aleurone = Blx and blx (11).
Hordeum vulgare Myb protein Colorless 1 ortholog 3 = HvMpc1-H3 is the third Blx gene (Blx1) (9); the Bowman backcross-derived line with blue aleurone (BW063) retained donor parent SNP markers from 2_1359 to 2_0670 (27.52 to 117.80 cM) in 4H bins 02 to 08 (2).

Monofactorial recessive (1, 4) when complementary dominant alleles are present at the Blx2, Blx3, Blx4, and Blx5 loci (3).
Located in chromosome 4HL (1, 7, 8);blx1.8 is over 13.6 cM distal from the glf3 (glossy leaf 3) locus (10).

Blue aleurone color is due to anthocyanin pigments (6), which occur as lumps inside many aleurone granules in some or all aleurone cells (3). Variation in blue color expression from dark blue to an off-white is caused by environmental factors and modifying genes (3, 4). 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 (5). HvMpc1-H3 (Blx1) is apparently the co-regulator of anthocyanin pigments accumulation in the aleurone layer (9).

Non-blue aleurone (blx1.a) is recessive allele that occurs in many cultivars, blx1.a is more frequently in two-rowed cultivars of Occidental origin, while the blue allele (Blx1) is more common in Oriental cultivars.

blx1.a (GSHO 185) in Goldfoil (PI 5975) (7).

blx1.a (GSHO 185) in Goldfoil; the dominant allele is present in Bowman (PI 483237).

1. Buckley, G.F.H. 1930. Inheritance in barley with special reference to the color of caryopsis and lemma. Sci. Agric. 10:460-492.
2. 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.
3. Finch, R. A., and E. Simpson. 1978. New colours and complementary colour genes in barley. Z. Pflanzenzücht. 81:40-53.
4. 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.
5. 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.
6. 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.
7. Myler, J.L., and E.H. Stanford. 1942. Color inheritance in barley. J. Am. Soc. Agron. 34:427-436.
8. Robertson, D.W., G.W. Deming, and D. Koonce. 1932. Inheritance in barley. J. Agric. Res. 44:445-466.
9. Strygina, K.V., and E.K. Khlestkina. 2019. Structural and functional divergence of the Mpc1 genes in wheat and barley. BMC Evolutionary Biology 19 (Suppl 1):45.
10. Takahashi, R., J. Hayashi, and I. Moriya. 1971. Linkage studies in barley. Barley Genet. Newsl. 1:51-58.
11. Wiebe, G.A. 1972. Blue aleurone caused by complementary genes in very close translinkage. Barley Genet. Newsl. 2:109.

T.E. Haus. 1975. Barley Genet. Newsl. 5:111.

R.A. Finch. 1978. Barley Genet. Newsl. 8:163.
J.D. Franckowiak and R.A. Finch. 1997. Barley Genet. Newsl. 26:60.
J.D. Franckowiak. 2018. Barley Genet. Newsl. 48:61-62.