Coordinator’s report: Chromosome 2H (2)

 

J.D. Franckowiak

 

Department of Plant Sciences

North Dakota State University

Fargo, ND 58105, U.S.A.

 

Hard-copy edition pages 13 - 21.

Marquez-Cedillo et al., 2001 published a more complete report on the analysis of agronomic traits in a doubled-haploid population from a cross between the two-rowed cv. Harrington and the six-rowed cv. Morex. The vrs1 (six-rowed spike 1) locus was associated with QTL effects for yield, kernel plumpness, test weight, and plant height across most test environments. A region of chromosome 2H proximal from the vrs1 locus was associated with early heading in all eight environments tested.

 

Schmierer et al., 2001 used a molecular marker-assisted backcross breeding scheme to demonstrate that molecular markers near QTLs for yield can be used to identify high yielding selections from crosses between the high yielding cv. Baronesse and the malting barley cv. Harrington. Based on studies in the BC₂ generation, two regions in chromosome 2HL and one region in chromosome 3HL were reported to contain potential QTLs for high yield. Studies on the next backcross generation further localized the yield QTLs. The QTL in 3HL was estimated to be between markers MWG571A and MWG961 in Bins 3H-09 and 3H-12, respectively. (See http://barleygenomics.wsu.edu for the latest barley Bin maps.) The two critical regions in 2HL were between Bmy2 and MWG699 (Bins 2H-07 and 2H-10) and between ABG072 and ksuD22 (Bins 2H-11 and 2H-12). Since Baronesse has the Vrs1.t (deficiens) allele at the vrs1 locus, which is located in Bin 2H-10, spike type might be useful as visual marker to identify segregates having as least one QTL for high yield.

 

Kolb et al., 2001 and Rudd et al., 2001 summarized recent mapping and breeding studies on resistant to Fusarium head blight (FHB) in barley and wheat. They reported that QTLs for FHB resistance were identified frequently in barley chromosome 2H. The critical region of chromosome 2H probably includes the vrs1 locus and the QTL for early maturity reported by Marquez-Cedillo et al., 2001. The early heading QTL is likely the same dominant, photoperiod sensitive gene identified by Tohno-oka et al., 2000 in Bin 2H-08 of Morex. The early maturity allele in Morex was tentatively named Eam6.h (Franckowiak, 2001).

 

Costa et al., 2001 mapped 12 morphological markers using molecular markers and the doubled-haploid population named the Oregon Wolfe Barleys. The loci vrs1, wst7 (white streak 7), and Zeo1 (zeocriton 1) were placed in chromosome 2HL in Bins 2H-10, 2H-15, and 2H-14, respectively. The relative positions of these morphological markers are similar to those reported based on studies using only morphological markers (Franckowiak, 1997).

 

In their study of doubled-haploid lines from a ‘Leger’/CIho 9831 cross, Frégeau-Reid et al., 2001 found that the vrs1 region of chromosome 2H has a major effect on feed quality parameters. Although they used the Vrs1.t (deficiens) allele instead of the Vrs1.b allele, they observed changes in the chemical other crosses between two- and six-rowed cultivars. Frégeau-Reid et al., 2001 also studied the effects of the Pre2 (red lemma and pericarp 2) gene on grain quality. The higher protein, low starch, and higher beta-glucan of purple seeded lines was composition similar to those reported for attributed to linkage between the Pre2 and vrs1 loci, a distance of about 11 cM. Frégeau-Reid et al., 1996 determined in a previous study of the same material that the deficiens lines produce larger, rounder seeds than six-rowed lines.

 

Castiglioni et al. 1998 demonstrated procedures for mapping morphological mutants using AFLP markers and placed branched spike mutant (brc-5) in chromosome 2HS about 2.5 cM from AFLP marker E3636-2. This marker is proximal from molecular marker CDO665A in Bin 2H-05. The brc-5 mutant causes rachillas in the basal part of the spike elongate to form rachis-like branches or a second-order ramification of the barley spike.

 

Pozzi et al., 2000 using AFLP markers and the map published by Castiglioni et al., 1998 mapped several calcaroides (cal) mutants and a leafy lemma (lel1) mutant. In the calcaroides mutants, lemma appendages or modifications are situated somewhat below the top of the lemma. Only one of the five cal loci was placed in chromosome 2H. The cal-a locus is in chromosome 2HS distal from molecular marker CDO057A and probably near Bin 2H-01. Since the sbk (subjacent hood) gene in chromosome 2HS is the only previously mapped calcaroides-like mutant, Pozzi et al., 2000 assumed that cal-a and sbk are alleles. This information provides a much better position estimate for the sbk locus than previous linkage studies (Franckowiak, 1997).

 

Scheurer et al., 2001 reported further on resistance to barley yellow dwarf virus strain BYDV-PAV and provided molecular mapping data that indicate two QTLs are associated with plant growth after infection. The main QTL from ‘Post’ is located near molecular marker HVCSG in Bin 2H-13 of chromosome 2H. The QTL from ‘Vixen’ is in chromosome 3HL and was identified as the Ryd2 (reaction to BYDV 2) gene.

 

References:

 

Castiglioni, P., C. Pozzi, M. Heun, V. Terzi, K.J. Müller, W. Rohde, and F. Salamini. 1998. An AFLP-based procedure for the efficient mapping of mutations and DNA probes in barley. Genetics 149:2039-2056.

 

Costa, J.M., A. Corey, P.M. Hayes, C. Jobet, A. Kleinhofs, A. Kopisch-Obusch, S.F. Kramer, D. Kudrna, M. Li, O. Riera-Lizarazu, K. Sato, P. Szucs, T. Toojinda, M.I. Vales, and R.I. Wolfe. 2001. Molecular mapping of the Oregon Wolfe Barleys: a phenotypically polymorphic doubled-haploid population. Theor. Appl. Genet. 103:415-421.

 

Franckowiak, J.D. 1997. Revised linkage maps for morphological markers in barley, Hordeum vulgare. BGN 26:9-21.

 

Franckowiak, J.D. 2001. Coordinator’s report: Chromosome 2H (2). BGN 31:45-51. http://wheat.pw.usda.gov/ggpages/bgn/31/ul1txt.htm#2H.

 

Frégeau-Reid, J., T.M. Choo, P. Jui, and K.M. Ho. 1996. Inheritance of kernel size and shape of barley. SABRAO J. 28:47-55.

 

Frégeau-Reid, J., T.M. Choo, K.M. Ho, R.A. Martin, and T. Konishi. 2001. Comparison of two-row and six-row barley for chemical composition using doubled-haploid lines. Crop Sci. 41:1737-1743.

 

Kolb, F.L., G-H. Bai, G.J. Muehlbauer, J.A. Anderson, K.P. Smith, and G. Fedak. 2001. Symposium on genetic solutions to Fusarium head blight in wheat and barley: Challenges, opportunities, and imperatives. Crop Sci. 41:611-619.

 

Marquez-Cedillo, L.A., P.M. Hayes, A. Kleinhofs, W.G. Legge, B.G. Rossnagel, K. Sato, S.E. Ullrich, and D. M. Wesenberg. 2001. QTL analysis of agronomic traits in barley based on the doubled haploid progeny of two elite North American varieties representing different germplasm groups. Theor. Appl. Genet. 103:625-637.

 

Pozzi, C., P. Faccioli, V. Terzi, A.M. Stanca, S. Cerioli, P. Castiglioni, R. Fink, R. Capone, K.J. Müller, G. Bossinger, W. Rohde, and F. Salamini. 2000. Genetics of mutations affecting the development of a barley floral bract. Genetics 154:1335-1346.

 

Rudd, J.C., R.D. Horsley, A.E. McKendry, and E.M. Elias. 2001. Host plant resistance genes for Fusarium head blight: Sources, mechanisms, and utility in conventional breeding systems. Crop Sci. 41:620-627.

 

Scheurer, K.S., W. Friedt, W. Huth, R. Waugh, and F. Ordon. 2001. QTL analysis of tolerance to a German strain of BYDV-PAV in barley (Hordeum vulgare L.). Theor. Appl. Genet. 103:1074-1083.

 

Schmierer, D., N. Kandemir, D. Kudrna, D. Wesenberg, S. Ullrich, and A. Kleinhofs. 2001. Molecular marker-assisted selection for increased yield of traditional malting barley cultivars. BGN 31:6-11. http://wheat.pw.usda.gov/ggpages/bgn/31/schmierer.htm.

 

Tohno-oka, T., M. Ishit, R. Kanatani, H. Takahashi, and K. Takeda. 2000. Genetic analysis of photoperiodic response of barley in different daylength conditions. p. 239-241. In S. Logue (ed.), Barley Genetics VIII. Proc. Eighth Int. Barley Genet. Symp., Departm. of Plant Science, Waite Campus, Adelaide University, Glen Osmond, South Australia 5064. Vol. 3:239-241.