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than high-yielding modern cultivars (assuming that high-yielding cultivars are more
sensitive to stresses than their traditional counterparts (Byerlee 1996 ).
In Syria, about 23 % of the increase in durum wheat production is due to effects
of irrigation, 34 % to the use of improved varieties, 24 % to fertilizer, and 19 % to
land and crop management, with 37 % of the impact coming from rainfed areas
(Mazid et al. 1998 ). In Turkey, improved varieties and efficient crop husbandry
practices resulted in a three-fold wheat yield in the last 50 years, from 0.8 to 2.4 t
ha−^1 (Avci 1999 ). This increase is predominantly caused by timely soil management
with proper implements (timely tillage, sowing, weeding, etc.), phosphorus applica-
tion, and improved varieties (Avci et al. 1987 ).
Barley is the world’s fourth most important cereal crop, and drought affects its
yields severely. During 2000 in Syria, for example, when rainfall dropped 20 to 30
% below the long-term average, the crop produced little or no grain in some areas.
Nonetheless, at four dryland experimental sites, a few barley lines were able to pro-
duce grain. Based on these materials, a new drought-tolerant barley variety was
developed, with the participation of farmers, through a plant breeding program
coordinated by the ICARDA. The economic benefit so far of participatory barley
improvement in Algeria, Egypt, Ethiopia, Iraq, Jordan, Morocco, Tunisia and Syria
was estimated at about US$91 million in 1997.
Pearl millet (Pennisetum glaucum (L.) R. Br.), the most inherently drought-
tolerant of all the major staples, together with sorghum (Sorghum bicolor (L.)
Moench) are key cereal grain crops in the drylands, providing food, feed and, in the
case of millet, fuel and construction material as well. Despite formidable obstacles
to improvement of these crops for drylands, plant breeders at the International
Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and in national part-
ner organizations have made important gains, and farmers are adopting new variet-
ies. In southern Africa, for example, about 34 % of the total millet area is now
planted to improved materials and 23 % of the sorghum area (CGIAR 2013 ).
Grain legume production is increasing worldwide due to their use directly as
human food, feed for animals, and industrial demands. Further, grain legumes have
the ability to enhance the levels of nitrogen and phosphorus in cropping systems
(Sinclair and Vadez 2012 ). Grain legumes are vital sources of low-cost protein in
drylands, and the sale of excess grain generates significant farm income. Grain
legumes also help restore soil fertility, since their roots fix nitrogen from the air in
forms that can be used by subsequent crops. In addition, the stems and stalks of
these crops are valued as livestock feed. Cowpea (Vigna unguiculata (L.) Walp.) is
the most widely grown grain legume in the dry areas of Africa, while chickpea and
pigeon pea (Cajanus cajan (L.) Millsp.) predominate in much of the Asian dry-
lands. More than 60 countries have released improved cowpea varieties with sup-
port from the International Institute of Tropical Agriculture (IITA). Chickpea (Cicer
arietinum L.) and pigeon pea varieties resulting from the work of ICRISAT are
having a major impact in India, Nepal, Pakistan and increasingly in China (CGIAR
2013 ).
Plant breeding in general, and cereal breeding in particular, was remarkably suc-
cessful during the second half of the 20th century, contributing substantially to keep
production ahead of population growth. The effect of plant breeding on durum
Q. Sohail et al.