Biotechnological Approcahes to Crop Improvement in the Dry Areas at the International Centre for Agricultural Research in the Dry Areas

Abstract

At the International Center for Agricultural Research in the Dry Areas biotechnology is included in the crop improvement and genetic resources programme. Emphasis is given to the identification and exploitation of genetic resources of improved stress resistance, particularly improved water use efficiency. Non-radioactive DNA technology is being utilized for fingerprinting genetic resources. Numerous molecular marker systems have also been used for genome mapping and gene tagging. Markers have already been identified, to be linked with traits of agronomic importance. The technology available for using these markers for marker-assisted selection (MAS) has also greatly improved. Fluorescent-labelled allele-specific markers are being developed and can be used with automated sequencers to allow the screening of thousands of lines within a short period as required by breeding programmes. The ability to use MAS to pyramid genes will make this technology an essential tool for breeders. Besides gene tagging and genome mapping, there is considerable effort to characterize the pathogen populations and to develop geographical distribution maps. These maps will allow the deployment of effective host plant resistance genes. In vitro techniques are being used to overcome species barriers to introgress agronomic traits of wild species into adapted cultivars. Embryo- and ovule rescue techniques are being used for interspecific and intergeneric hybridization programmes. Somaclonal variation is exploited from regenerants of Lathyrus explants to reduce neurotoxins in the plant and seed tissue. Doubled haploid (DH) breeding is being used when rapid solutions are required. Anther and isolated microspore culture systems are being used for the development of doubled haploid lines for barley and wheat. DH breeding for the barley programme is used to develop mapping populations for drought tolerance. DH breeding for the wheat programmes is used specifically to introgress Hessian fly (Mayetiola destructor) resistance for North Africa and yellow rust (Puccinia striiformis f.sp. tritici) resistance into adapted germplasm. When variability for key traits is low, genetic engineering is being used to incorporate new genes into plant materials. Fungal and abiotic stress resistance is being engineered in chickpea in cooperation with the University of Hannover, Germany and insect and abiotic stress resistance is being engineered in lentils in cooperation with the Center for Legumes in Mediterranean Agriculture, Australia.