BGS 16, Waxy endosperm 1, wax1

Waxy endosperm = wx (12).
High amylopectin endosperm = glx (3, 8).

Monofactorial recessive (5, 7).
Located in chromosome 7HS (4, 11); wax1.a is about 1.5 cM proximal from the fch12 (chlorina seedling 12) locus (12); wax1.a is about 12.6 cM proximal from the Run1 (reaction to Ustilago nuda 1) locus (10); wax1.a is associated with SNP markers 2_0303 to 1_0451 (positions 0.0 to 41.79 cM) in 7H bins 01 to 03 of the Bowman backcross-derived line BW905 (1), likely in 7H bin 02.

The endosperm contains primarily amylopectin, chains of alpha- (14) D-glucopyranose units branched through alpha-(16) linkages, and has a waxy texture. The starch content is reduced, the amount of sucrose and maltose is increased significantly, and more amylodextrin may be deposited (6). The starch in the endosperm and pollen grains has reddish-brown reaction to iodine (5, 7). The estimated spontaneous reversion to normal for six wax1 alleles ranged from 1.9 to 5.6 x 10-5, and the intralocus recombination frequencies ranged from 0.4 to 194 x 10-5 (8). Instability of the wax1.a allele from R.I. Wolfe’s Multiple Recessive Stock is induced by crossing to mutant line 152 (9).

A spontaneous mutant in Murasaki Mochi (CIho 5899) (5, 7).

wax1.a (GSHO 84) in Murasaki Mochi (CIho 5899) (5, 7); wax1.b, wax1.c, wax1.d, wax1.e, wax1.f, and wax1.g in Steptoe (CIho 15229) (3, 8).

wax1.a (GSHO 85) in Oderbrucker (CIho 4666)*10 (Waxy Oderbrucker, CIho 7563, GSHO 908); wax1.a from R.I. Wolfe's Multiple Recessive Stock in Bowman (PI 483237)*8 (GSHO 1828, BW905, NGB 22336).

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. Franckowiak, J.D. (Unpublished).
3. Kleinhofs, A., R.L. Warner, F.J. Muelbauer, and R.A. Nilan. 1978. Induction and selection of specific gene mutations in Hordeum and Pisum. Mutat. Res. 51:29-35.
4. Kramer, H.H., and B.A. Blander. 1961. Orientating linkage maps on the chromosomes of barley. Crop Sci. 1:339-342.
5. Nakao, S. 1950. On waxy barleys in Japan. Seiken Ziho 4:111-113. [In Japanese with English summary.]
6. Newman, C.W., and R.K. Newman. 1992. Nutritional aspects of barley seed structure and composition. p. 351-368. In P.R. Shewry (ed.) Barley: Genetics, Biochemistry, Molecular Biology, and Biotechnology. (Biotechnology in Agriculture no. 5). CAB International, Wallingford, UK.
7. Ono, T., and H. Suzuki. 1957. Endosperm characters in hybrids between barley varieties with starchy and waxy endosperms. Seiken Ziho 8:11-19.
8. Rosichan, R.A., P. Arenaz, and A. Kleinhofs. 1979. Intragenic recombination at the waxy locus in Hordeum vulgare. Barley Genet. Newsl. 9:79-85.
9. Schreiber, H., and A. Habekuß. 1996. High frequencies of forward and reverse genetic changes at the waxy-locus of barley (Hordeum vulgare L.). Barley Genet. Newsl. 25:41-45.
10. Shands, R.G. 1964. Inheritance and linkage to stem rust and loose smut resistance and starch type in barley. Phytopathology 54:308-316.
11. Shapter, F.M., P. Eggler, L.S. Lee, and R.J. Henry. 2009. Variation in Granule Bound Starch Synthase I (GBSSI) loci amongst Australian wild cereal relatives (Poaceae). J. Cereal Sci. 49:4-11.
12. Tabata, M. 1961. Studies of a gametophyte factor in barley. Jpn. J. Genet. 36:157-167.
13. Webster, O.J. 1950. Genetics and morphology of rachis internode length. Ph.D. Thesis. Univ. of Minnesota, St. Paul.

T.E. Haus. 1975. Barley Genet. Newsl. 5:97.

T. Tsuchiya. 1982. Barley Genet. Newsl. 12:109.
J.D. Franckowiak and T. Konishi. 1997. Barley Genet. Newsl. 26:61-62.
J.D. Franckowiak 2012. Barley Genet. Newsl. 42:65-66.