Virus Resistance in Barley - Translational Genomics for Crop Breeding: Biotic Stress - page 63

Chapter 5

Virus Resistance inBarley

FrankOrdonand DraganPerovic

Abstract

Barley ( Hordeum vulgare L.), which is a diploid species with 2n 14 chromosomes and a genome

size of about 5.2 Gb, is one of the most important crop species worldwide. It is the host for more than
50 different viruses, of which the soil-borne Barley yellow mosaic virus (BaYMV) and Barley mild
mosaic virus (BaMMV) and the aphid-transmitted Barley yellow dwarf virus (BYDV) and Cereal
yellow dwarf virus (CYDV) have a serious impact on barley production due to high yield losses
frequently observed in susceptible barley crops. Breeding for resistance/tolerance is the only way to
ensure barley production in the growing area of fields infected by soil-borne viruses and to prevent
infections by aphid-transmitted viruses in an environmentally sound manner. In barley, genomic tools
are available today that pave the way to (1) efficient marker-based selection procedures for virus
resistance, (2) the enhanced isolation of resistance genes via a map-based cloning approach, and (3)
efficient allele mining and allele-based breeding strategies for virus resistance. The present state and
future perspectives of breeding for virus resistance in barley using these genomic tools are briefly
reviewed.

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Introduction lands, United Kingdom, and Denmark), average

barley yields today are nearly 7.0 tons per hectare
(all statistics are from http://faostat.fao.org). B ar-
ley is mainly used for animal feed, malting, and,
to a lesser extent, directly for human nutrition.
Barley is a diploid species (2n

Barley ( Hordeum vulgare ) ranked fifth in acreage
among major crops in 2010, covering about
47.5 million hectares worldwide, and it was
number two in Europe next to wheat, with an
acreage of about 23 million hectares. On the
worldwide level, in 2010, barley yields aver-
aged about 2.6 tons per hectare; in the European
Union they were 4.3 tons per hectare. However,
in the main barley-growing countries of West-
ern Europe (France, Germany, Belgium, Nether-

14) that
was cultivated in the Fertile Crescent some
10,500 years ago (Zohary and Hopf 2000), and
it is regarded as one of the founder crops of
Old World agriculture (Badr et al. 2000). Bar-
ley has a genome size of about 5.2 Gb (Aruma-
ganathan and Earle 1991), and due to diploidy,

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