259affects protein content, dough quality, and decrease glutenin to gliadin ratio
(Blumenthal et al. 1995 ).
A regional plant genetic resources (PGR) network has recently been established
under the auspices of the Association of Agricultural Research Institutions in the
Near East and North Africa (AARINENA), as a platform for regional collaboration
in setting agriculture priorities to cope with global change. Gene bank in the
International Centre for Agricultural Research in the Dry Areas (ICARDA) holds
more than 131,000 accessions of cereals, food and feed legumes, and forages includ-
ing cultivated varieties, landraces and wild relative species, representing more than
50 % of the conserved genetic resources originating from the drylands of Central
and West Asia and North Africa. At ICARDA, several promising lines with good
tolerance to drought have been derived from inter-specific crosses of barley
(Hordeum vulgare L.) and wheat (Triticum aestivum L.). Wild relatives of different
crops have sustained recurrent drought and heat cycles that allowed natural selec-
tion to develop resistance to these stresses; these plants therefore may harbor valu-
able genes for these stresses (FAO 2011 ).
In this chapter, efficient crops for dryland systems are introduced, and breeding
and genetic enhancement strategies for improving the productivity of dryland crops
are discussed.
2 Efficient Crops for Dryland System
The choice of crops for the production systems, cultivar, sowing date, plant density,
fertilizer management, and control of diseases, insects, and weeds, needs to best suit
the local environmental conditions. Given the low and erratic precipitation for crop
production in the dry areas, further research should focus on improving water-use
efficiency associated with increased production per unit area, and improved produc-
tion stability. The development of new, well-adapted varieties, efficient crop pro-
duction and crop production technologies are among the most important factors
involved in enhancing crop productivity in dryland agriculture. Among the crops,
wheat, barley, millet, sorghum and grain legumes have great potential for drylands.
Wheat and barley are the most important cereal crops in Mediterranean, where
high temperatures and water scarcity restricts yield during grain filling (Araus et al.
2007 ; Francia et al. 2011 ; Jacobsen et al. 2012 ). Modern wheat cultivars have been
normally selected for improved productivity under high-yielding conditions,
whereas barley or traditional wheat were somehow better adopted to poor environ-
ments compared to modern high-yielding wheats (Ryan et al. 2008 ). On the other
hand, barley is the dominant cereal crop in the dryland systems of the Mediterranean
region (as well as in many other low yielding systems) as farmers assume that barley
performs better compared to wheat under these conditions (Cossani et al. 2007 ;
Ryan et al. 2008 ). Farmers in these systems tend to favor the use of traditional rather
Breeding and Genetic Enhancement of Dryland Crops