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Plant Genetic Resources and Plant Improvement as Tools to Develop Sustainable Agriculture
- S. Ceccarelli, J. Valkoun, W. Erskine, S. Weigand, R. Miller, J. A. G. Van Leur
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- Journal:
- Experimental Agriculture / Volume 28 / Issue 1 / January 1992
- Published online by Cambridge University Press:
- 03 October 2008, pp. 89-98
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This paper addresses the current and future contributions of plant genetic resources and plant improvement to sustainable agriculture with reference to the activities of the International Center for Agricultural Research in the Dry Areas (ICARDA) in association with national programmes in West Asia and North Africa. These regions constitute the primary centres of diversity of crops such as wheat, barley, chickpea and lentil. Genetic erosion is being curtailed by germplasm collection and preservation. Selection for low-input cultivars of barley is conducted under low input conditions, and new cultivars of lentil and barley are often intentionally heterogeneous to stabilize their performance in dry rainfed areas. The importance of genetic differences in the cultivars on subsequent crops in the rotation and on straw quality for livestock is under study. Insect pests and diseases contribute to yield instability. Because of the potential adverse impact of pesticides on the fragile ecosystems of the region, integrated control strategies based on agronomic management, host plant resistance, biological control agents and strategic use of selective insecticides are being developed.
Towards a conservation strategy for Aegilops species
- N. Maxted, K. White, J. Valkoun, J. Konopka, S. Hargreaves
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- Journal:
- Plant Genetic Resources / Volume 6 / Issue 2 / August 2008
- Published online by Cambridge University Press:
- 14 May 2008, pp. 126-141
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Aegilops species provide an invaluable source of genes for the improvement of cultivated wheats. This paper illustrates how the existing geo-referenced passport data associated with Aegilops species can be used to identify gaps in current conservation and also to develop a more systematic conservation strategy for the genus. Taxonomic, ecological, geographic and conservation information for the 22 Aegilops species were collated from ICARDA, EURISCO, GRIN and SINGER datasets, synthesized and analysed. The combined database contained 9866 unique geo-referenced observations collected between 1932 and 2004. Patterns of specific distribution based on the germplasm accession data and the predicted distribution using climatic models were compared in conservation gap analysis using GIS tools. The ex situ conservation status of each taxon was assessed and used to provide a priority ranking. Future ex situ collection is recommended in Cyprus, Egypt, Greece, Iran, Israel, Libya, Spain, Syria, Tajikistan, Tunisia, Turkey, Turkmenistan and Uzbekistan. The species identified with the highest ex situ conservation priority are as follows: Aegilops bicornis, Aegilops comosa, Aegilops juvenalis, Aegilops kotschyi, Aegilops peregrina, Aegilops sharonensis, Aegilops speltoides, Aegilops uniaristata and Aegilops vavilovii. Patterns of species richness based on the germplasm accession passport data are presented and five complementary regions of Aegilops diversity were identified in west Syria and north Lebanon, central Israel, north-west Turkey, Turkmenistan and south France. Within these areas, 16 IUCN-recognized protected areas are found and these are identified as potential sites to establish genetic reserves. However, the premier Aegilops hotspots on the Syrian/Lebanese border are not coincident with any existing internationally recognized protected areas, and here there is a need to establish a novel protected area.
Chapter 15 - Barley
- Edited by Dominic Fuccillo, University of Arkansas, Linda Sears, International Plant Genetic Resources Institute, Rome, Paul Stapleton, International Plant Genetic Resources Institute, Rome
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- Book:
- Biodiversity in Trust
- Published online:
- 22 September 2009
- Print publication:
- 28 August 1997, pp 191-212
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Summary
Barley is a cool-season crop in countries with a Mediterranean climate and is well adapted to stressful and extreme environments. Barley fields can be seen as high as 4800 m asl in the Himalayas, in latitudes over 60°N in Iceland and Scandinavia and in the rain-fed semi-arid regions of WANA with less than 250 mm annual rainfall. Barley is a principal food crop in highlands and marginal areas where other cereals will not grow, as well as animal feed and forage all over the world. It is also an important industrial crop, providing raw material for malt and beer production. Its straw is of better quality than that of wheat and is, therefore, a valuable complement of cattle and small ruminant diets. Barley is grown in a wide range of environments but nearly two-thirds of the world's production is grown in subhumid or semi-arid regions.
BOTANY AND DISTRIBUTION
Barley belongs to the tribe Triticeae of the grass family Poaceae together with other important cereals, wheat and rye. The main distinction from other members of the tribe is that each spike node bears three 1-flowered spikelets (‘triplets’) of which one, two or all three are fertile. The genus Hordeum includes about 30 species (Bothmer 1992a). According to the same author, the 45 taxa of the genus are mostly diploid (2n=2x=14 chromosomes, 28 taxa), but also tetraploid (2n=4x=28 chromosomes, 16 taxa) and hexaploid (2n=6x=42 chromosomes, 8 taxa) with a basic chromosome number x=7.
Chapter 21 - Wheat
- Edited by Dominic Fuccillo, University of Arkansas, Linda Sears, International Plant Genetic Resources Institute, Rome, Paul Stapleton, International Plant Genetic Resources Institute, Rome
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- Book:
- Biodiversity in Trust
- Published online:
- 22 September 2009
- Print publication:
- 28 August 1997, pp 309-320
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Summary
Wheat is grown in almost all cropping environments of the world, except in the humid lowland tropics. Winter wheat under rain-fed conditions dominates in Europe, the USA, Ukraine and southern Russia, followed by spring-sown spring wheat in semi-arid conditions (Canada, Kazhakstan and Siberia) in the developed world. In the developing world, wheat is usually not a subsistence crop and its production is concentrated in several well-defined cropping systems: double-cropped with paddy rice in Asia (22 million ha) or with maize, cotton, soybean or berseem (15 million ha); with soybean in the Southern Cone (7 million ha). Only in the wetter parts of the developed world, such as the eastern USA, Europe and southern Russia, and in parts of the Southern Cone, is wheat grown in more complex rotational systems involving pulses, oilseeds, other cereals, alfalfa and pastures. An exception is southern Australia, where, despite low rainfall, complex rotations and ley farming are practised.
BOTANY AND DISTRIBUTION
Origin, Distribution and Diffusion
Wheat belongs to the genus Triticum, which originated about 10 000 years ago in what is now the Middle East. Polyploid Triticum arose when two diploid wild grasses crossed naturally to produce tetraploid wheat, which today includes cultivated durum wheat (Triticum turgidum L. var. group durum Desf. 2n=4x=28). Tetraploid wheat later outcrossed to goat grass (T. tauschii, considered a troublesome weed in many wheat-growing areas) and gave rise to hexaploid bread wheat (T. aestivum L. em Thel. 2n=6x=42).