Author
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Jaradat, Abdullah |
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Submitted to: Emirates Journal of Food and Agriculture
Publication Type: Other Publication Acceptance Date: 6/5/2013 Publication Date: 1/1/2014 Publication URL: http://handle.nal.usda.gov/10113/58399 Citation: Jaradat, A.A. 2014. The value of wheat landraces (Editorial). Emirates Journal of Food and Agriculture. DOI: 10.9755/efja.v26i2.16745. Interpretive Summary: Technical Abstract: Whether man was domesticated by wheat, or wheat was domesticated by man is but two faces of the same coin; both incidents marked a turning point in human history and led to the emergence of human civilization in the Fertile Crescent of the Old World. The complex history of wheat domestication from its progenitor, wild emmer wheat, followed by the evolution of domesticated durum, then bread wheat, and the subsequent development of a multitude of wheat landraces, testify to the ingenuity of those early "farmers" who recognized its potential, as a food crop, among the swarms of grasses that once covered that part of the world. Ever since its domestication, and throughout the last ~10,000 years, farmers have been behind the development, improvement and on-farm conservation of wheat genetic diversity, mostly as landraces. Thousands of years of cultivation aided by natural and human selection resulted in the evolution of immense diversity in wheat. A number of socio-cultural factors, food traditions, and agro-ecological environments in the Old World favored the cultivation and utilization of diverse wheat genetic resources constituting what is now known as landraces. Each wheat landrace has particular significance in the food culture, as a source of daily diet, and of food and drink for special occasions. Wheat landraces can be considered as an evolutionary link between wild emmer wheat and modern-day wheat cultivars. Recently, however, many wheat landraces have been lost due to the introduction of modern wheat varieties, disappearance of traditional farming systems, the aging and exodus of rural population, and accelerated environmental degradation. Wheat landraces have been largely replaced, in their centers of diversity by monocultures of modern varieties, which are pure genotypes. This genetic erosion resulted in significant loss of valuable genetic diversity for quality traits and resistance or tolerance to biotic and abiotic stresses; whereas, the pure wheat genotypes do not have the wide adaptation and the diverse genetic background already present in landraces. Climate change is expected to differentially affect components of complex biological interactions in modern and traditional wheat production systems. Wheat yield and quality will be affected directly and indirectly by climate change. The manner with which wheat landraces and their populations in and outside their centers of diversity might respond to climate change will determine their continued productivity, utility, and survival for the benefit of humanity. Traditional management of wheat landraces contributed more to the conservation of a general level of diversity, as a source of sustenance and sustainability, than to the conservation of genetically stable and distinct populations. Wheat landraces embody not only diverse alleles and genotypes, but also evolutionary processes such as gene flow between different populations, mainly via seed exchange and local knowledge systems such as folk taxonomies and information about selection for specific quality attributes or for heterogeneous environments. Characterization of the population structure of wheat landraces is critical to identify and correctly interpret the association between their functional and molecular diversity. Such information is essential to utilize landraces as donors of traits in wheat breeding, to define the areas of adaptation of different landraces, to identify priority areas for on-farm conservation, and to understand the genetic consequences of the interaction between climate change, growing environments and farmers' practices. The objective of this special issue of The Emirates Journal of Food and Agriculture was to provide a forum for wheat scientists to exchange research results and forge joint research plans, exchange germplasm and revive global interest in wheat landraces. The manuscri |
