Future Directions and Prospects
According to some estimates (Fischer 2009), the global wheat production must increase at least by 1.6 % annually during 2005–2020 to meet a projected wheat demand of 760 million tons by 2020. In the year 2050, the world population is estimated to be nine billion (Alexandratos 2009) and the demand for wheat reaches more than 900 million tons. Fulfilling this increasing demand for wheat is very challenging with the current scenario of climate change (IPCC 2007; Battisti and Naylor 2009), increasing drought/water shortage, soil degradation, reduced supply & increasing cost of fertilizers, increasing demand for bio-fuel, and emergence of new virulent diseases and pests. Offsetting these challenges requires understanding of the drivers of past trends and future changes in wheat production, and designing an effective research strategy for gene mining, introgression and deployment with the application of new technologies and tools.
Located in the heart of the Fertile Crescent, ICARDA houses more than 41,000 wheat accessions of wheat including rich collections of landraces, primitive wheat, Aegilops and wild Triticum species. Synthetic hexaploid wheat (SHWs) produced by artificial resynthesis of bread wheat through hybridization between Ae. tauschii and T. turgidum are also available in the genebank. These wheat germplasm are novel sources of resistance genes against biotic and abiotic stresses for wheat production (Ogbonnaya et al. 2001; van Ginkel and Ogbonnaya 2007). However, despite the existence of this promising resource of new genes, there has been limited deployment and/or effective use in cultivated bread wheat mainly due to the high cost of screening of such huge number of accessions and the potential simultaneous transfer of deleterious genes. The development of Focused Identification of Germplasm Strategy (FIGS) and the availability of new molecular tools such as genotyping-by-sequencing (GBS) would enable to characterize and mine novel genes and alleles effectively and rapidly from such gene bank accessions. It is also important to apply modern tools including genome-wide selection, and advanced statistical analysis of multi-location evaluation data for wheat breeding in order to allow faster integration of desirable traits and improve breeding efficiency, especially for complex traits such as grain yield under optimum, drought, and heat conditions (Ferrara et al. 1987; Braun et al. 2010).
Major efforts are needed to break yield barrier in wheat to increase wheat yield potential by 50 % in order to cope the growing demand for wheat. Increasing the radiation use efficiency of wheat through modification of key enzymes (e.g., Rubisco) and biochemical pathways to increase photosynthesis, ear size and lodging resistance are key areas of wheat research through integration of physiological and molecular breeding methodologies to increase wheat yield potential. Further increase in yield potential would be achieved through the development of hybrid wheat systems based on native and transgenic interventions in collaborative approach, leveraging private sector technologies for the benefit of partners and stakeholders in the developing world.
The International Wheat Improvement Network (IWIN) coordinated by CIMMYT and ICARDA has been the most successful and efficient network for making available and widespread distribution of new wheat genotypes globally (Payne 2004; Reynolds and Borlaug 2006; Dixon et al 2009; Byerlee and Dubin 2010). Such a network need to be strengthened through the establishment of other net-works and collaborations in order to develop, disseminate, and market more productive, stress tolerant, and nutritive wheat varieties, and to perfect and promote production practices based on the principles of conservation agriculture that boost yields while conserving or enhancing critical resources like soil and water.