BGS 69, Toothed lemma 1, Gth1

Toothed lemma = G (5, 9).

Monofactorial dominant (7, 8), but modifiers were reported (5, 7).
Located in chromosome 2HL (5, 9); Gth1.a is about 15.4 cM proximal from the vrs1 (six-rowed spike 1) locus (2, 4, 7); gth1.b is associated with SNP markers 2_0528 to 1_0823 (positions 118.78 to 133.59 cM) in 2H bins 08 to 09 of the Bowman backcross-derived line BW413 (1); the association of palea trichome develop with spike type (4) suggests that alleles at Gth1 locus also control this trait.

Large teeth or barbs are present on the upper part of lateral lemma nerves. The barbs are easiest to see on green spikelets. This trait may be difficult to study because Ubisch (8) reported three sizes of teeth, including one that could be seen only with magnification. According to Ubisch (8), one gene pair controls the presence and absence of large teeth and one or two other genes are responsible for less developed teeth. Segregation for only one pair of factors is reported by Wexelsen (9) and in subsequent studies. Other reports on inheritance of lemma teeth were summarized by Smith (6). Besides barbs on the lateral lemma veins and slight heavier kernels, no other agronomic or morphological differences were observed between Bowman and the Bowman backcross-derived line for gth1.b, BW413 (3). Association of trichomes with vascular bundle traces may not be limited to the lemma because similar variations in shape of trichomes were observed on the palea (4). Trichomes with a round base and a domed peak appeared predominantly on two-rowed cultivars. But most of the six-rowed cultivars featured trichomes with a similar base, but a prickle-like point that aligned with the direction of elongation of the epidermal cells (4). The palea trichomes may play a role in infection by the scab fungus, Fusarium graminearum, because the prickle-type trichomes functioned to trap conidia and were sites of fungal penetration (4).

Gth1.a appears to be the normal allele; while the recessive allele gth1.b is present in many two-rowed barley cultivars of Occidental origin (4)..

Gth1.a (GSHO 309) in Machine (CIho 4982) (9); gth1.b is present in many two-rowed cultivars of European origin (9); gth1.b is present in many two-rowed cultivars of European origin (4).

Gth1.a (GSHO 309) in Machine; Gth1.a is present in Bowman (PI 483237); gth1.b from ND11894 (Gitane//ND4642/Robust/3/Bearpaw/4/TR218/ND701 ND7015/3/ Norbert//ND4856/M38) in Bowman*4 (GSHO 1897); gth1.b in Bowman*6 (BW413, NGB 20646).

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. Finch, R. A., and E. Simpson. 1978. New colours and complementary colour genes in barley. Z. Pflanzenzücht. 81:40-53.
3. Franckowiak, J.D. (Unpublished).
4. Imboden, L., D. Afton, and F. Trail. 2017. Surface interactions of Fusarium graminearum on barley. Mol. Plant Path. 19:1332-1342.
5. Karpechenko, G.D., and K.V. Ivanova. 1932. Linkage of genes I and G in barley. Bull. Lab. Genet. Leningrad 9:97-108. [In Russian with English summary.]
6. Smith, L. 1951. Cytology and genetics of barley. Bot. Rev. 17:1-51, 133-202, 285-355.
7. Tschermak, E. von. 1901. Über Züchtung neuer Getreiderassen mittelst künstlicher Kreuzung. Kritisch-historische Betrachtungen. Zeitschrift für das landwirtschaftliche Versuchswesen Oesterreich 4:1029-1060.
8. Ubisch, G. von. 1919. Beitrag zu einer Faktorenanalyse von Gerste. II. Z. Indukt. Abstammungs. Vererbungsl. 20:65-117.
9. Wexelsen, H. 1934. Quantitative inheritance and linkage in barley. Hereditas 18:307-348.

T.E. Haus. 1975. Barley Genet. Newsl. 5:109.

T.E. Haus. 1978. Barley Genet. Newsl. 8:161.
J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:106.
J.D. Franckowiak. 2014. Barley Genet. Newsl. 44:68-69.