BGS 488, Laxatum-ef, lax-ef

Laxatum-225 = lax-225 (6, 7).
Laxatum-238 = lax-238 (6, 7).

Monofactorial recessive (5).
Located likely in chromosome 2H (2); lax-ef.225 is associated with SNP markers 2_1187 to 2_0528 (positions 51.62 to 118.78 cM) in chromosome 2H bins 05 to 08 and with small segments of chromosomes 3HS, 5HS, 5HL, and 6HS of the Bowman backcross-derived line BW462 (2).

Rachis internodes of lax-ef.238 spikes were about 23% longer than those of Bonus (7). Leaf blades were relatively wide and darker green; spikes had more fertile rachis nodes, and the straw was very weak when dry (7). Plants of the Bowman backcross-derived line for lax-ef.225, BW462, headed three days later than Bowman and had rachis internodes that were nearly 30% longer (5.7 vs. 4.4 mm). Compared to Bowman, BW462 plants had slightly shorter peduncles and awns; and spikes had about 4 to 6 more kernels (5). Kernels were slightly longer and thinner and weighed less (5.3 vs. 6.0 mg). Grain yields of BW462 were 10 to 20% lower than those of Bowman (5). The delayed heading of BW462 could be attributed to 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 Foma (1, 2).

lax-ef.225 is a glycidol induced mutant in Foma (NGB 14659, CIho 11333) (2, 9); lax-ef.238 is an ethylene imine induced mutant in Foma (7, 9).

lax-ef.205 (NGB 116432), -ef.225 (NGB 116453), -ef.236 (NGB 116463), -ef.237 (NGB 116466), -ef.238 (NGB 116467), -ef.263 (NGB 116488), -ef.287 (NGB 116512), -ef.290 (NGB 116514), -ef.292 (NGB 116516), -ef.309 (NGB 116532) in Foma (NGB 14659, CIho 11333) (3, 4, 7, 8).

lax-ef.225 (NGB 116453) in Foma; lax-ef.225 in Bowman (PI 483237)*3 (BW462, NGB20692).

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.
3. Ehrenberg, L., Å. Gustafsson, and U. Lundqvist. 1961. Viable mutants induced in barley by ionizing radiations and chemical mutagens. Hereditas 47:243-282.
4 Franckowiak, J.D. (Unpublished).
5. 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.
6. Larsson, H.E.B. 1985. Morphological analysis of laxatum barley mutants. Hereditas 103:239-253.
7. Larsson, H.E.B. 1985. Genetic analysis of laxatum barley mutants. Hereditas 103:255-267.
8. Lundqvist, U. (Unpublished).

H.E.B. Larsson and U. Lundqvist. 1986. Barley Genet. Newsl. 16:71,.

U. Lundqvist and J.D. Franckowiak. 2017. Barley Genet. Newsl. 47:154-155