International Database for Barley Genes and Barley Genetic Stocks

BGS 639, NADH nitrate reductase-deficient 3 (molybdenum cofactor), nar3

BGN  35:196
Stock number: BGS 639
Locus name: NADH nitrate reductase-deficient 3 (molybdenum cofactor)
Locus symbol: nar3

Previous nomenclature and gene symbolization:



Monofactorial recessive (4).
Location in chromosome 7HS (1); nar3.a3 is near molecular marker MWG836 in 7H bin 05 (1).


The nar3 mutants are characterized by a pleiotropic loss of nitrate reductase and xanthine dehydrogenase activity due to defective molybdenum cofactor synthesis or insertion (3). The nar3 mutants are lethal and must be maintained as heterozygotes (2).
No images

Origin of mutant:

An ethyl methanesulphonate induced mutant in Winer (4).

Mutational events:

nar3.a3 (Xno18) in Winer (3); nar3.b2 (Xno19) in Winer (4); nar3.x (Az71) in Steptoe (CIho 15229) (2).

Mutant used for description and seed stocks:

nar3.x (Az71) in Steptoe.


1. Kleinhofs, A. 1997. Integrated barley RFLP and classical marker maps. Barley Genet. Newsl. 27:105-112.

2. Kleinhofs, A. (Unpublished).

3. Kleinhofs, A., R.L. Warner, J.M. Lawrence, J.M. Melzer, J.M. Jeter, and D.A. Kudrna. 1989. Molecular genetics of nitrate reductase in barley. p. 197-211. In J.L. Wray and J.R. Kinghorn (eds.) Molecular and Genetic Aspects of Nitrate Assimilation, Chapter 13. Proc. 2nd Int. Symp. on Nitrate Assimilation - Molecular and Genetic Aspects, St. Andrews, July, 1987. Oxford Univ. Press, New York.

4. Tokarev, B.I., and V.K. Shumny. 1977. Detection of barley mutants with low level of nitrate reductase activity after seed treatment with ethylmethane sulphonate. Genetika (Moskva) 13:2097-2103.


A. Kleinhofs. 2005. Barley Genet. Newsl. 35:197.