BGS 99, Lesser internode number 1, lin1

Rachis internode number = s, rin (3, 6).
Low number of rachis internodes = rin (4).
Rachis internode length QTL on 2H = qSIL.ak-2H (5).

Monofactorial recessive (6, 7).
Located in chromosome 2HS (7); lin1.a is about 15.1 cM distal from the eog1 (elongated outer glume 1) locus and about 17.1 cM proximal from the vrs1 (six-rowed spike 1) locus (6); lin1.a is about 6 cM proximal from STS marker ABG602 and the Eam1 (Early maturity 1) locus (5), likely in 2H bin 07.

The mean number of rachis internodes per spike is reduced by 20 to 40% (6. 7). The average internode number was 15.3 in Triple Bearded Mariout and 22.9 in Spartan (6). Presence of the Eam1 (Early maturity 1) gene closely linked to lin1.a gene in Triple Bearded Mariout (BGS 57) made study of lin1 locus difficult in some environments; therefore, a new BGS number was recommended (2). In some six-rowed cultivars such as Morex, the reduction in rachis internodes associated with the lin1 gene is less obvious (1). A significant reduction triplet number, 1.5 to 2.3 fertile rachis nodes, was associated with the Azumamugi allele in 2HS and mapped near the Eam1 (Early maturity 1) locus (5). Since mapping population was grown under short-day conditions, the effects of the Eam1 gene on maturity and plant development were not expressed (5). The effects of alleles at the lin1 locus on fertile rachis nodes are more obvious when barley is grown in heat stressed environments. Fewer fertile rachis nodes per spike may lead to plumper kernels. The lin1.a gene is likely present in Bowman and may be associated with tolerance to heat stress (1).

Natural occurrence in many six-rowed barley cultivars of North African and Asian origin (1). Tavcar’s mutant stock is no longer available.

lin1.a in Triple Bearded Mariout (CIho 2523, GSHO 29) (6).

lin1.a in Morex (CIho 15773, GSHO 2492); lin1.a from Nordic (CIho 15216) is present in Bowman (PI 483237).

1. Franckowiak, J.D. (Unpublished).
2. Franckowiak, J.D. 2002. BGS 99, Lesser internode number 1, lin1. Barley Genet. Newsl. 32:88.
3. Freisleben, R., and I. Metzger. 1942. Genetische Studien zur Gerstenzüchtung. I. Vererbung und Koppelung der Mehltauresistenz und der Spindelgliedzahl. Z. f. Pflanzenzücht. 24:507-522.
4. Robertson, D.W., G.A. Wiebe, and F.R. Immer. 1941. A summary of linkage studies in barley. J. Am. Soc. Agron. 33:47-64.
5. Sameri, M., K. Takeda, and T. Komatsuda. 2006. Quantitative trait loci controlling agronomic traits in recombinant inbred lines from a cross of oriental- and occidental-type barley cultivars. Breed. Sci. 56:243-252.
6. Swenson, S.P., and D.G. Wells. 1944. The linkage relation of four genes in chromosome 1 of barley. J. Am. Soc. Agron. 36:429-435.
7. Tavcar, A. 1938. Vererbungsart der Spindelstufenzahl bei Bastardierungen einiger distichum x vulgare Wintergersten. Z. Indukt. Abstammungs. Vererbungsl. 75:106-123.

T. Tsuchiya and T.E. Haus. 1971 Barley Genet. Newsl. 1:117 as BGS 57, Reduced internode number, rin.

T. Tsuchiya and T.E. Haus. 1984. Barley Genet. Newsl. 14:91 as BGS 57, Lesser internode number, lin.
J.D. Franckowiak. 2002. Barley Genet. Newsl. 32:88: BGS number changes from BGS 57 to BGS 99.
J.D. Franckowiak. 2011. Barley Genet. Newsl. 41:92-93.