BGS 485, Laxatum-n, lax-n

Laxatum-67 = lax-67 (6, 7).

Monofactorial recessive (8).
Located in chromosomes 2H, 4HL, or 5H (2); lax-n.67 is associated with SNP markers 2_1187 to 2_0887 (positions 51.62 to 103.73 cM) in 2H bins 05 to 08, with SNP markers 2_0496 to 2_11332 (positions 72.70 to 112.64 cM in 4H bins 05 to 07, and with SNP markers 2_0010 to 2_1244 (positions 28.11 to 91.91 cM) in 5H bins 02 to 05 of the Bowman backcross-derived line BW469 (2).

Rachis internodes of lax-n.67 were about 4% longer than those of Bonus, the awns were coiled, leaf blades were narrow, and kernel weights were low (7). Plants of the Bowman backcross-derived line for lax-n.67, BW469, headed about three days later than Bowman and had rachis internodes that were slightly longer (4.8 vs. 4.5 mm). Compared to Bowman, BW469 plants had slightly shorter awns and had two to four more kernels per spike (5). Kernels weighed slightly less than those of Bowman (5.5 vs. 6.0 mg). The awns of BW469 plants were slightly twisted (5). The delayed heading of BW469 and greater number of fertile rachis could be caused by the presence of the late allele at the Early maturity 6 (Eam6) or Praematurum-c (mat-c) locus, which was retained in the 2H segment from the donor parent Bonus (1, 2).

An ethylene imine induced mutant in Bonus (NGB 14657, PI 189763) (7, 9).

lax-n.67 (NGB 116400), -n.68 (NGB 116401) in Bonus (NGB 14657, PI 189763) (7, 8).

lax-n.67 (NGB 116400) in Bonus; lax-n.67 in Bowman (PI 483237)*3 (BW469, NGB20699).

1. Comadran, J., B. Kilian, J. Russell, L. Ramsay, N. Stein, M. Ganal, P. Shaw, M. Bayer, W. Thomas, D. Marshall, P. Hedley, A. Tondelli, N. Pecchioni, E. Francia, V. Korzun, A. Walther, and R. Waugh. 2012. Natural variation in a homolog of Antirrhinum CENTRORADIALIS contributed to spring growth habit and environmental adaptation in cultivated barley. Nature Genet. 44:1388-1392.
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. Ehrenberg, L., Å. Gustafsson, and U. Lundqvist. 1959. The mutagenic effects of ionizing radiations and reactive ethylene derivatives in barley. Hereditas 45:351-368.
4. Ehrenberg, L., Å. Gustafsson, and U. Lundqvist. 1961. Viable mutants induced in barley by ionizing radiations and chemical mutagens. Hereditas 47:243-282.
5. Franckowiak, J.D. (Unpublished).
6. Gustafsson, Å., A. Hagberg, U. Lundqvist, and G. Persson. 1969. A proposed system of symbols for the collection of barley mutants at Svalöv. Hereditas 62:409-414.
7. Larsson, H.E.B. 1985. Morphological analysis of laxatum barley mutants. Hereditas 103:239-253.
8. Larsson, H.E.B. 1985. Genetic analysis of laxatum barley mutants. Hereditas 103:255-267.
9. Lundqvist, U. (Unpublished).

H.E.B. Larsson and U. Lundqvist. 1986. Barley Genet. Newsl. 16:68.

U. Lundqvist and J.D. Franckowiak. 2017. Barley Genet. Newsl. 47:150-151.