BGS 491, Laxatum-hf, lax-hf

Laxatum-244 = lax-244 (6, 7).

Monofactorial recessive (5).
Located in chromosomes 2H, 3HL or 5H (2); partially sterile F1 plants indicated that a translocation was present in lax-hf.244 (6); lax-hf.244 is associated with SNP markers 2_1338 to 2_1242 (positions 74.97 to 133.59 cM) in chromosome 2H bins 05 to 08, with SNP markers 2_0931 to 2_0009 (positions 104.39 to 164.68 cM) in chromosome 3H bins 07 to 11, and with SNP markers 1_1381 to 2_0392 (positions 11.26 to 109.27 cM) in chromosome 5H bins 01 to 06 of the Bowman backcross-derived line BW464 (2). Based on translocation testers, lax-hf.244 was previously associated with chromosome 5HL (9).

Rachis internodes of lax-hf.244 plants were about 21% longer than those of Bonus (7). Leaf blades were relatively narrow and darker green; spikes were long, and kernels were relatively thin (7). A translocation could be present in the original lax-hf.244 stock based on semisterility of the F1s following a cross to Foma (8). Plants of the Bowman backcross-derived line for lax-hf.244, BW464, headed two to three days later than Bowman and had rachis internodes that were about 15% longer (5.2 vs. 4.5 mm). Compared to Bowman, BW464 plants had slightly shorter peduncles and awns and had about four more kernels per spike (5). Kernels were longer (10.5 vs. 9.3 mm), thinner (3.3 vs. 3.8 mm) and weighed less (5.3 vs. 6.0 mg). Grain yields of BW464 were 15 to 20% lower than those of Bowman (5). The delayed heading of BW464 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-hf.244 is an ethyl methanesulfonate induced mutant in Foma (NGB 14659, CIho 11333) (7, 10).

lax-hf.232 (NGB 116460), -hf.242 (NGB 116472), -hf.244 (NGB 116474), -hf.251 (NGB 116478) in Foma (NGB 14659, CIho 11333) (3, 4, 8, 10).

lax-hf.244 (NGB 116474) in Foma; lax-hf.244 in Bowman (PI 483237)*4 (BW464, NGB20694).

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. Larsson, H.E.B. 1985. Linkage studies with genetic markers and some laxatum barley mutants. Hereditas 103:269-279.
10. Lundqvist, U. (Unpublished).

H.E.B. Larsson and U. Lundqvist. 1986. Barley Genet. Newsl. 16:74.

U. Lundqvist and J.D. Franckowiak. 2017. Barley Genet. Newsl. 47:158-159.