BGS 136, Reaction to Puccinia hordei 7 (barley leaf rust), Rph7

Resistance to Puccinia hordei Otth y = Pay (7).
Resistance to Puccinia hordei Otth 5 = Pa5 (10).
Resistance to Puccinia hordei Otth 7 = Pa7 (8).

Monofactorial dominant (7, 10).
Located in chromosome 3HS (14, 15); linkage to markers in the centromeric region was reported (11); Rph7.g is about 24.0 cM from the ant17 (proanthocyanidin-free 17) locus (5); Rpg7.g is about 1.3 cM distal from RFLP marker cMWG691 in 3H bin 01 (6); Rpg7.g is about 3.2 cM from receptor-like kinase gene Hv3Lrk (2); Rph7.g is about 7.0 cM proximal from Rph5 (Reaction to Puccinia hordei 5 (leaf rust) locus (16).

The seedling reaction type is 0;n - 1c (4, 11). Temperature studies show that resistance conferred by the Rph7.g gene is not expressed well above 20ºC (4, 15). Cebada Capa is indistinguishable from the cultivar Forrajera Klein (possibly identical to PI 331904) (1). The Rph7 regions from Morex (rph7) and Cebada Capa (Rph7) were sequenced and compared to similar regions from 39 other cultivars. The data suggest that a large amount of haplotype variability exists in the cultivated barley gene pool and indicate rapid and recent divergence at this locus (12).

Natural occurrence in Cebada Capa (PI 53911) (7, 8, 10).

Rph7.g (GSHO 1318) in Cebada Capa (PI 53911) (7, 8, 10); Rph7.g in France 7 and France 21 (7); Rph7.g in Dabat, Gondar (PI 199964), and La Estanzuela (9, 13, 16); Rph7.ac in Tu17a, a Bowman backcross-derived line from Tunisia 17 (3).

Rph7.g (GSHO 1318) in Cebada Capa; Rph7.g in Bowman (PI 483237)*8 (GSHO 1994, PI 643156, BW758, NGB 22464), Rph7.ac (Tu17a) from Tunisia 17 in Bowman*6 (GSHO 2328); Rph7.ac (in Bowman*8 (BW757, NGB 22463).

1. Arias, G. (Personal communications).
2. Brunner, S., B. Keller, and C. Feuillet. 2000. Molecular mapping of the Rph7.g leaf rust resistance gene in barley (Hordeum vulgare L.). Theor. Appl. Genet. 101:783-788.
3. Chicaiza, O., J.D. Franckowiak, and B.J. Steffenson. 1996. New sources of resistance to leaf rust in barley. p. 706-708. In A.E. Slinkard, G.J. Scoles, and B.G. Rossnagel (eds.) Proc. Fifth Int. Oat Conf. & Seventh Int. Barley Genet. Symp., Saskatoon. Univ. of Saskatchewan, Saskatoon.
4. Clifford, B.C., and H. W. Roderick. 1981. Detection of cryptic resistance of barley to Puccinia hordei. Trans. Br. Mycol. Soc. 76:17-24.
5. Falk, D.E. 1985. Genetic studies with proanthocyanidin-free barley. Barley Genet. Newsl. 15:27-30.
6. Graner, A., S. Streng, A. Drescher, Y. Jin, I. Borovkova, and B.J Steffenson. 2000. Molecular mapping of the leaf rust resistance gene Rph7 in barley. Plant Breed. 119:389-392.
7. Johnson, R. 1968. The genetics of resistance of some barley varieties to Puccinia hordei. p. 160-162. In Proc. Eur. Medit. Cereal Rust Conf., Oeiras, Portugal.
8. Nover, I., and C.O. Lehmann. 1974. Resistenzeigenschaften im Gersten- und Weizensortiment Gatersleben. 18. Prüfung von Sommergersten auf ihr Verhalten gegen Zwergrost (Puccinia hordei Otth). Kulturpflanze 22:25-43.
9. Parlevliet, J.E. 1976. The genetics of seedling resistance to leaf rust, Puccinia hordei Otth, in some spring barley cultivars. Euphytica 25:249-254.
10. Roane, C.W., and T.M. Starling. 1970. Inheritance of reaction to Puccinia hordei in barley. III. Genes in the cultivars Cebada Capa and Franger. Phytopathology 60:788-790.
11. Roane, C.W., and T.M. Starling. 1989. Linkage studies with genes conditioning leaf rust reaction in barley. Barley Newsl. 33:190-192.
12. Scherrer, B., E. Isidore, P. Klein, J.-S. Kim, A. Bellec, B. Chalhoub, B. Keller, and C. Feuillet. 2005. Large intraspecific haplotype variability at the Rph7 locus results from rapid and recent divergence in the barley genome. Plant Cell 17:361-374.
13. Tan, B.H. 1978. Verifying the genetic relationships between three leaf rust resistance genes in barley. Euphytica 27:317-323.
14. Tuleen. N.A., and M.E. McDonald. 1971. Location of genes Pa and Pa5. Barley Newsl. 15:106-107.
15. Udeogalanya, A.C.C., and B.C. Clifford. 1976. Genetical, physiological and pathological relationships of resistance to Puccinia hordei and P. striiformis in Hordeum vulgare. Trans. Br. Mycol. Soc. 71:279-287.
16. Zhong, S., R.J. Effertz, Y. Jin, J.D. Franckowiak, and B.J. Steffenson. 2003. Molecular mapping of the leaf rust resistance gene Rph6 in barley and its linkage relationships with Rph5 and Rph7. Phytopathology 93:604-609.

J.D. Franckowiak and Y. Jin. 1997. Barley Genet. Newsl. 26:173.

J.D. Franckowiak. 2007. Barley Genet. Newsl. 37:228-229.