Use of biotechnological tools and novel genetic resources for enhancing resilience of major dryland crops to climate change in dry areas.

摘要

Food security for the fast growing population will depend on our ability to produce more per unit area without depleting the resources base,and on facilitated access of population to food commodities.The development of improved varieties with higher and stable yields has contributed to food security for the commodities of global importance such as wheat,rice,maize which are at the origin of the green revolution.Currently the Global wheat productivity is increasing at a rate of 0.9 t/ha.Further genetic gains in yields will depend on access and use of novel genetic diversity and use of biotechnology tools to increase the efficiency of breeding programs.ICARDA has one of the richest collections of cereals and legumes totaling 153,000 accessions composed mainly of landraces and wild relatives which should be mined for useful genes.Introgressions from wild wheat relatives have been important sources of genetic variation: Sr2,1B/1R and Lr19 are three examples with major impacts in both the developing and developed world wheat production.Biotechnology has played significant roles in improving agricultural production.For instance,embryo rescue in vitro has allowed the development of synthetic hexaploid wheat from crosses between durum wheat and Aegilops tauschii which is contributing significantly to enlarge the genetic base of bread wheat.Synthetic hexaploid wheats have enabled to mobilize the wealth of genes available in the D genome progenitor of wheat,Ae.tauschii.New alleles are identified in the progenies using molecular markers techniques.Tissue culture is routinely used for the production of doubled haploids in wheat and barley which reduces significantly the time to bread new lines.Diagnostic markers are used in ICARDA mandated crops for marker-assisted selection.For location of genes,quantitative traits loci(QTL)mapping in biparental populations and association mapping in germplasm collections are being used.TILLING populations in various crops have been developed and are being used to identify genes responsible for various different stresses.EcoTILLING is being used to utilize natural variation of known genes.In this paper,different approaches of using biotechnological tools and novel genetic resources for enhancing resilience of major dry land crops to climate change in dry areas are discussed.