Abstract
p ]Genetic erosion occurs as a result of disruption of the natural habitat by humankind or through the replacement of traditional landraces or ecotypes by modern cultivars. It may occur because of a decline in a species’ diversity through the reduction of its geographical distribution or through the complete loss of a species. Within a species a decline in genetic diversity is caused by the loss of genetic information through the reduction of its distribution and population size. Comparison of the current geographical distribution of a species with its past distribution can be used to assess the degree of genetic erosion that has occurred. Quantified assessment of genetic erosion is possible using species diversity indices and measures of genetic diversity.
Although there is some evidence of genetic erosion in pasture and forage legumes of the Mediterranean, it is only circumstantial. Much of this evidence is from observations of loss of habitats to development and intensification of agriculture, and in particular, the increase of grazing pressure in many areas where it has been equated with a reduction in the distribution of species. There is an urgent need to quantify the extent of genetic erosion in the Mediterranean more accurately by determining a baseline of the original species distributions in the region and precisely defining the current distribution of species. Genetic diversity of older original collections of species should be quantified and compared with that of current natural populations to determine if there has been a reduction in the genetic diversity of natural populations.
Pasture and forage species within a genus have different ecological niches, and as such are not interchangeable. Increasing genetic erosion may result in the loss of species or genes that may have potential in Mediterranean agricultural systems, or could be useful in extending the geographical range of a species currently used in agriculture.
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References
Annicchiarico, P. (1990). Collecting Ladino white clover ecotypes in the Po Valley. Plant Genet. Res. Newslett. 85, 25–27.
Anon, (1985). Forages for Mediterranean and adjacent arid/semi-arid areas. Report of a Working Group, held at Limassol, Cyprus, 24-26 April 1985. IBPGR Secretariat, Rome.
Bounejmate, M., Robson, A.D. and Beale, P.E. (1992). Annual Medicago species in Morocco I. Species and their Abundance. Aust J Agric. Res 43, 739–749.
Bounejmate, M., Gintzburger, G., Christiansen, S., Robertson, L.D., Abd El Moneim A. and Konopka, J. (1998). ICARDA invests heavily in forage and pasture legume genetic resources conservation and utilisation for the future of semi-arid zones in West Asia and North Africa. In ‘Proceedings of a CLIMA Workshop on Genetic Resources of Mediterranean Pasture and Forage Legumes’, 14–18 October 1996. (Eds. S.J. Bennett and P.S. Cocks) (Kluwer: The Hague).
Bowman, K.O., Hutcheson, K., Odum, E.P. and Shenton, L.R. (1971). Comments on the distribution of indices of diversity. Stat Ecol 3, 315–366.
Brown, A.D.H. and Weir, B.S. (1983). Measuring genetic variability in plant populations. In ‘Isozymes in Plant Genetics and Breeding, Part A’, (eds. S.D. Tanksley and T.J. Orton) pp. 219–239.(Elsevier Science: Amsterdam).
Carter, E.D. (1981). Seed and seedling dynamics of annual medic pastures in South Australia. Proc. XIV Int. Grassland Congress, pp.447-450.
Cowling, W.A. (1986). Collection of wild Lupinus in Greece. Plant Genet Res. Newslett. 65, 20–22.
Ehrman, T. and Cocks, P.S. (1990). Ecogeography of annual legumes in Syria: distribution patterns. J Appl Ecol 27, 578–579.
Francis, C.M. (1987). Morocco, a plant collection tour. A report compiled for the Grain Research Development Corporation, Agriculture Western Australia, Perth.
Francis, C.M., Bounejmate, M. and Robertson, L.D. (1994). Observations on the distribution and ecology of Vicia and Lathyrus species in northern Morocco. Al Awamia 84, 17–27.
Goodrich, W.J. (1987). Monitoring genetic erosion: detection and assessment. IBPGR/87/33. IBPGR, Rome.
Guardino, L. (1995). Assessing the threat of genetic erosion. In ‘Collecting Plant Genetic Diversity: Technical Guidelines’ (Eds. L. Guarino, V.R. Rao, and R. Reid), pp. 67–74 (CAB International: Wallingford, UK).
Hammer, K. and Perrino, P. (1995). Plant genetic resources in south Italy and Sicily — studies towards in situ and on-farm conservation. Plant Genet. Res. Newlett. 103 19–23.
Hammer, K., H. Knüpffer, L. Xhuveli and Perrino, P. (1996). Estimating genetic erosion in landraces — two case studies. Genet. Res. Crop Evol. 43, 329–336.
Harlan, J.R. (1983). The scope for collection and improvement of forage plants. In ‘Genetic Resources of Forage Plants’ (Eds. J.G. Mclvor and R.A. Bray), pp. 63–84 (CSIRO: East Melbourne, Australia).
Houérou, le N.N. (1991). Forage species diversity in Africa: an overview of the genetic resources. In ‘Crop Genetic Resources of Africa, Vol. 1 ‘. (Eds. F. Attéré, H. Zedan, N.Q. Ng and P. Perrino). pp. 99–117. (IBPGR: Rome).
Houérou, Le H.N. and Boulos, L. (1991). Bioclimatic and phytogeographic characteristics of the and rangelands of northern African and the Near East. In IVth International Rangeland Congress Vol 1, Montpellier 22-26 April 1991.’ (Eds. A.N. Gaston, M. Kernick and H.N. le Houérou.) pp. 535–542. (CIRAD: Montpellier, France).
Hutcheson, K. (1970). A test for comparing diversities based on the Shannon formula. J. Theor. Biol. 29, 151–154.
IBPGR. (1986). Genetic Erosion: monitoring and assessment. AGPG:IBPGR/86/89. IBPGR, Rome.
IBPGR (1991). ‘Elsevier’s Dictionary of Plant Genetic Resources’. Elsevier Science Publishers, B.V., Amsterdam.
Lesins, K.A. and Lesins, I. (1979). Genus Medicago (Leguminosae): A Taxonomic Study. (Dr W. Junk bv Publishers: The Hague).
Lewis, C.E., Swindel, B.F. and Tanner, G.W. (1988). Species diversity and diversity profiles: Concept, measurement, and application to timber and range management. J. Range Man. 41, 466–469.
Negre, R. 1956. Les luzernes du Maroc. Travaux de l’Institut Scientifique Cherifien. Maroc, Serie Botanique 5:xxii, 1-120.
Negre, R. 1959. Revision del Medicago d’Afrique du Nord. Bulletin de la Société d’Historié Naturelle d’Afrique du Nord 50, 267–314.
Mathison, M.J, (1983). Mediterranean and temperate forage legumes. In ‘Genetic Resources of Forage Plants’ (Eds. J.G. Mclvor and R.A. Bray). pp. 63–84 (CSIRO: East Melbourne, Australia).
Nei, M., (1973). Analysis of gene diversity in subdivided populations. Proc. Nat. Acad. Sci. 70, 147–157.
Parkin, R.J. (1966). Stocking rates on Cyprus barrel medicin the northern wheatbelt. J Agric WA 7, 276–279.
Patil, G.P. and Taillie, C. (1982). Diversity as a concept and its measurement. J Am. Stat. Assoc. 77, 548–561.
Perrino, P., Polignano, G.B. Sui-Kwong, J. and Khouya-Ali, M. (1986). Collecting Germplasm in Southern Morocco. FAO/IBPGR Plant Gen. Res. News. 65, 26–28.
Pottier-Alapetite, G. (1979). ‘Flore de la Tunisie, Vol 1: Angiosperms — Dicotyledons: Apteatles — Dialypetales’. Publications Scientifiques Tunisiennes No. 644. Imp. Officielle de la Republique Tunisie.
Simpson, E.H. (1949). Measurement of diversity. Nature 163, 688.
Smith, A. and Robertson, L.D.(Eds.) (1991). ‘Legume Genetic Resources for Semi-Arid Temperate Environments’. Proceedings of an International Workshop on Genetic Resources of Cool-season Pasture, Forage, and Food Legumes for Semi-arid Temperate Environments, Cairo, Egypt 19-24 June 1987. (ICARDA: Aleppo, Syria).
Swindel, B.F., Conde, L.F. and Smith, J.E. (1984). Species diversity: Concept, measurement, and response to clear-cutting and site-preparation. For Ecol. Man. 8, 11–22.
Zohary, D. and Hopf, M. (1988). ‘Domestication of plants in the old world’. (Clarendon Press: Oxford, UK).
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Robertson, L.D., Bounejmate, M. (1999). Genetic erosion of pasture and forage legumes in the Mediterranean basin. In: Bennett, S.J., Cocks, P.S. (eds) Genetic Resources of Mediterranean Pasture and Forage Legumes. Current Plant Science and Biotechnology in Agriculture, vol 33. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-4776-7_6
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DOI: https://doi.org/10.1007/978-94-011-4776-7_6
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