Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-05T05:47:30.821Z Has data issue: false hasContentIssue false
  • English
  • Français

Genetic erosion in crops: concept, research results and challenges

Published online by Cambridge University Press:  19 October 2009

Mark van de Wouw ,
Chris Kik ,
Theo van Hintum ,
Rob van Treuren  and
Bert Visser
Mark van de Wouw*
Affiliation:
Centre for Genetic Resources, The Netherlands (CGN), Wageningen University and Research Centre, Wageningen, The Netherlands
Chris Kik
Affiliation:
Centre for Genetic Resources, The Netherlands (CGN), Wageningen University and Research Centre, Wageningen, The Netherlands
Theo van Hintum
Affiliation:
Centre for Genetic Resources, The Netherlands (CGN), Wageningen University and Research Centre, Wageningen, The Netherlands
Rob van Treuren
Affiliation:
Centre for Genetic Resources, The Netherlands (CGN), Wageningen University and Research Centre, Wageningen, The Netherlands
Bert Visser
Affiliation:
Centre for Genetic Resources, The Netherlands (CGN), Wageningen University and Research Centre, Wageningen, The Netherlands
*
*Corresponding author. E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The loss of variation in crops due to the modernization of agriculture has been described as genetic erosion. The current paper discusses the different views that exist on the concept of genetic erosion in crops. Genetic erosion of cultivated diversity is reflected in a modernization bottleneck in the diversity levels that occurred during the history of the crop. Two stages in this bottleneck are recognized: the initial replacement of landraces by modern cultivars; and further trends in diversity as a consequence of modern breeding practices. Genetic erosion may occur at three levels of integration: crop, variety and allele. The different approaches in the recent literature to measure genetic erosion in crops are reviewed. Genetic erosion as reflected in a reduction of allelic evenness and richness appears to be the most useful definition, but has to be viewed in conjunction with events at variety level. According to the reviewed literature, the most likely scenario of diversity trends during modernization is the following: a reduction in diversity due to the replacement of landraces by modern cultivars, but no further reduction after this replacement has been completed.

Keywords

genetic erosioncrop diversitymodernization bottleneck
Type
Research Article
Information
Plant Genetic Resources , Volume 8 , Issue 1 , April 2010 , pp. 1 - 15
Copyright
Copyright © NIAB 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Allard, RW (1996) Genetic basis of the evolution of adaptedness in plants. Euphytica 92: 1–11.CrossRefGoogle Scholar
Almanza-Pinzon, MI, Khairallah, M, Fox, PN and Warburton, ML (2003) Comparison of molecular markers and coefficients of parentage for the analysis of genetic diversity among spring bread wheat accessions. Euphytica 130: 77–86.CrossRefGoogle Scholar
Bardsley, D and Thomas, I (2005) Valuing local wheat landraces for agrobiodiversity conservation in Northeast Turkey. Agriculture Ecosystems & Environment 106: 407–412.CrossRefGoogle Scholar
Barry, MB, Pham, JL, Beavogui, S, Ghesquiere, A and Ahmadi, N (2008) Diachronic (1979–2003) analysis of rice genetic diversity in Guinea did not reveal genetic erosion. Genetic Resources and Crop Evolution 55: 723–733.CrossRefGoogle Scholar
Baur, E (1914) Die Bedeutung der primitiven Kulturrassen und der wilden Verwandten unserer Kulturpflanzen für die Pflanzenzüchtung. Jahrbuch der Deutschen Landwirtschafts Gesellschaft 29: 104–110.Google Scholar
Bennett, E (1973) Wheats of the Mediterranean basin. In: Frankel, OH (ed.) Survey of Crop Genetic Resources in Their Centre of Diversity. First Report: FAO – IBP, pp. 1–8.Google Scholar
Bitocchi, E, Nanni, L, Rossi, M, Rau, D, Bellucci, E, Giardini, A, Buonamici, A, Vendramin, GG and Papa, R (2009) Introgression from modern hybrid varieties into landrace populations of maize (Zea mays ssp. mays L.) in central Italy. Molecular Ecology 18: 603–621.CrossRefGoogle Scholar
Boches, P, Bassil, NV and Rowland, L (2006) Genetic diversity in the highbush blueberry evaluated with microsatellite markers. Journal of the American Society for Horticultural Science 131: 674–686.CrossRefGoogle Scholar
Bonifacio, A (2003) Chenopodium sp.: genetic resources, ethnobotany, and geographic distribution. Food Reviews International 19: 1–7.CrossRefGoogle Scholar
Brennan, JP and Fox, PN (1998) Impact of CIMMYT varieties on the genetic diversity of wheat in Australia, 1973–1993. Australian Journal of Agricultural Research 49: 175–178.CrossRefGoogle Scholar
Brinckmann, J and Smith, E (2004) Maca culture of the Junin plateau. Journal of Alternative and Complementary Medicine 10: 426–430.CrossRefGoogle ScholarPubMed
Brush, S, Kesseli, R, Ortega, R, Cisneros, P, Zimmerer, K and Quiros, C (1995) Potato diversity in the Andean center of crop domestication. Conservation Biology 9: 1189–1198.CrossRefGoogle ScholarPubMed
Buckler, ES, Thornsberry, JM and Kresovich, S (2001) Molecular diversity, structure and domestication of grasses. Genetical Research 77: 213–218.CrossRefGoogle ScholarPubMed
Buerkert, A, Oryakhail, M, Filatenko, AA and Hammer, K (2006) Cultivation and taxonomic classification of wheat landraces in the upper Panjsher valley of Afghanistan after 23 years of war. Genetic Resources and Crop Evolution 53: 91–97.CrossRefGoogle Scholar
Caicedo, AL, Williamson, SH, Hernandez, RD, Boyko, A, Fledel-Alon, A, York, TL, Polato, NR, Olsen, KM, Nielsen, R, McCouch, SR, Bustamante, CD and Purugganan, MD (2007) Genome-wide patterns of nucleotide polymorphism in domesticated rice. PLos Genetics 3: 1745–1756.CrossRefGoogle ScholarPubMed
Christiansen, MJ, Andersen, SB and Ortiz, R (2002) Diversity changes in an intensively bred wheat germplasm during the 20th century. Molecular Breeding 9: 1–11.CrossRefGoogle Scholar
Clark, RM, Linton, E, Messing, J and Doebley, JF (2004) Pattern of diversity in the genomic region near the maize domestication gene tb1. Proceedings of the National Academy of Sciences of the United States of America 101: 700–707.CrossRefGoogle ScholarPubMed
Dawe, D (2003) The monoculture myth. Rice Today 2: 33.Google Scholar
Dobrotvorskaya, TV, Martynov, SP and Pukhalskyi, VA (2004) Trends in genetic diversity change of spring bread wheat cultivars released in Russia in 1929–2003. Russian Journal of Genetics 40: 1245–1257.CrossRefGoogle Scholar
Doebley, JF, Gaut, BS and Smith, BD (2006) The molecular genetics of crop domestication. Cell 127: 1309–1321.CrossRefGoogle ScholarPubMed
Ellstrand, NC and Elam, DR (1993) Population genetic consequences of small population size – implications for plant conservation. Annual Review of Ecology and Systematics 24: 217–242.CrossRefGoogle Scholar
Erskine, W, Chandra, S, Chaudhry, M, Malik, IA, Sarker, A, Sharma, B, Tufail, M and Tyagi, MC (1998) A bottleneck in lentil: widening its genetic base in south Asia. Euphytica 101: 207–211.CrossRefGoogle Scholar
Evenson, RE (2003) Production impacts of crop genetic improvement. In: Evenson, RE and Gollin, D (eds) Crop Variety Improvement and Its Effect on Productivity, The Impact of International Agricultural Research. Wallingford: CABI publishing, pp. 447–471.CrossRefGoogle Scholar
Ford-Lloyd, BV (2006) Realistic population and molecular genetic approaches to genetic assessment. In: Ford-Lloyd, BV, Dias, SR and Bettencourt, E (eds) Genetic Erosion and Pollution Assessment Methodologies. Proceedings of PGR Forum Workshop 5, Terceira Island, Autonomous Region of the Azores, Portugal, 8–11 September 2004. Rome: Bioversity International, pp. 51–54.Google Scholar
Fowler, C and Mooney, P (1990) Shattering: Food, Politics, and The Loss of Genetic Diversity. Tucson: The University of Arizona Press.Google Scholar
Frankel, OH and Bennett, E (1970) Genetic Resources – Introduction. In: Frankel, OH and Bennett, E (eds) Genetic Resources in Plants – Their Exploration and Conservation, IPB Handbook No. 11. London: International Biological Programme, pp. 7–18.Google Scholar
Fraser, EDG (2003) Social vulnerability and ecological fragility: building bridges between social and natural sciences using the Irish Potato Famine as a case study. Conservation Ecology: 7.Google Scholar
Fu, YB, Diederichsen, A, Richards, KW and Peterson, G (2002) Genetic diversity within a range of cultivars and landraces of flax (Linum usitatissimum L.) as revealed by RAPDs. Genetic Resources and Crop Evolution 49: 167–174.CrossRefGoogle Scholar
Fu, YB, Peterson, GW, Scoles, G, Rossnagel, B, Schoen, DJ and Richards, KW (2003) Allelic diversity changes in 96 Canadian oat cultivars released from 1886 to 2001. Crop Science 43: 1989–1995.CrossRefGoogle Scholar
Fu, YB, Peterson, GW, Richards, KW, Somers, D, DePauw, RM and Clarke, JM (2005) Allelic reduction and genetic shift in the Canadian hard red spring wheat germplasm released from 1845 to 2004. Theoretical and Applied Genetics 110: 1505–1516.CrossRefGoogle ScholarPubMed
Fu, YB, Peterson, GW, Yu, JK, Gao, LF, Jia, JZ and Richards, KW (2006) Impact of plant breeding on genetic diversity of the Canadian hard red spring wheat germplasm as revealed by EST-derived SSR markers. Theoretical and Applied Genetics 112: 1239–1247.CrossRefGoogle ScholarPubMed
Fu, YB, Peterson, GW and Morrison, MJ (2007) Genetic diversity of Canadian soybean cultivars and exotic germplasm revealed by simple sequence repeat markers. Crop Science 47: 1947–1954.CrossRefGoogle Scholar
Gao, LZ (2003) The conservation of Chinese rice biodiversity: genetic erosion, ethnobotany and prospects. Genetic Resources and Crop Evolution 50: 17–32.CrossRefGoogle Scholar
Gepts, P (2006) Plant genetic resources conservation and utilization: the accomplishments and future of a societal insurance policy. Crop Science 46: 2278–2292.CrossRefGoogle Scholar
Hammer, K and Khoshbakht, K (2005) Towards a ’red list’ for crop plant species. Genetic Resources and Crop Evolution 52: 249–265.CrossRefGoogle Scholar
Hammer, K and Laghetti, G (2005) Genetic erosion – examples from Italy. Genetic Resources and Crop Evolution 52: 629–634.CrossRefGoogle Scholar
Hammer, K, Knupffer, H, Xhuveli, L and Perrino, P (1996) Estimating genetic erosion in landraces – two case studies. Genetic Resources and Crop Evolution 43: 329–336.CrossRefGoogle Scholar
Hao, C, Wang, L, Zhang, X, You, G, Dong, Y, Jia, J, Liu, X, Shang, X, Liu, S and Cao, Y (2006a) Genetic diversity in Chinese modern wheat varieties revealed by microsatellite markers. Science in China, Series C: Life Sciences 49: 218–226.CrossRefGoogle ScholarPubMed
Hao, CY, Zhang, XY, Wang, LF, Dong, YS, Shang, XW and Jia, JZ (2006b) Genetic diversity and core collection evaluations in common wheat germplasm from the Northwestern Spring Wheat Region in China. Molecular Breeding 17: 69–77.CrossRefGoogle Scholar
Harlan, JR (1970) Evolution of cultivated plants. In: Frankel, OH and Bennett, E (eds) Genetic Resources in Plants – IBP Handbook No 11. London: International Biological Programme, pp. 19–32.Google Scholar
Harlan, JR (1975) Our vanishing genetic resources. Science 188: 618–621.CrossRefGoogle ScholarPubMed
Harlan, JR and de Wet, JMJ (1971) Toward a rational classification of cultivated plants. Taxon 20: 509–517.CrossRefGoogle Scholar
Heal, G, Walker, B, Levin, S, Arrow, K, Dasgupta, P, Daily, G, Ehrlich, P, Maler, KG, Kautsky, N, Lubchenco, J, Schneider, S and Starrett, D (2004) Genetic diversity and interdependent crop choices in agriculture. Resource and Energy Economics 26: 175–184.CrossRefGoogle Scholar
Hernandez-Verdugo, S, Luna-Reyes, R and Oyama, K (2001) Genetic structure and differentiation of wild and domesticated populations of Capsicum annuum (Solanaceae) from Mexico. Plant Systematics and Evolution 226: 129–142.CrossRefGoogle Scholar
Huang, XQ, Wolf, M, Ganal, MW, Orford, S, Koebner, RMD and Roder, MS (2007) Did modern plant breeding lead to genetic erosion in European winter wheat varieties? Crop Science 47: 343–349.CrossRefGoogle Scholar
Hyten, DL, Song, QJ, Zhu, YL, Choi, IY, Nelson, RL, Costa, JM, Specht, JE, Shoemaker, RC and Cregan, PB (2006) Impacts of genetic bottlenecks on soybean genome diversity. Proceedings of the National Academy of Sciences of the United States of America 103: 16666–16671.CrossRefGoogle ScholarPubMed
IPGRI (2002) Neglected and Unterutilized Plant Species: Strategic Action Plan of the International Plant Genetic Resources Institute. Rome: International Plant Genetic Resources Institute.Google Scholar
Ishikawa, R, Yamanaka, S, Fukuta, Y, Chitrakon, S, Bounphanousay, C, Kanyavong, K, Tang, LH, Nakamura, I, Sato, T and Sato, YI (2006) Genetic erosion from modern varieties into traditional upland rice cultivars (Oryza sativa L.) in northern Thailand. Genetic Resources and Crop Evolution 53: 245–252.CrossRefGoogle Scholar
Jana, S and Pietrzak, LN (1988) Comparative assessment of genetic diversity in wild and primitive cultivated barley in a center of diversity. Genetics 119: 981–990.CrossRefGoogle Scholar
Jarvis, DI and Hodgkin, T (1999) Wild relatives and crop cultivars: detecting natural introgression and farmer selection of new genetic combinations in agroecosystems. Molecular Ecology 8: S159–S173.CrossRefGoogle Scholar
Jordan, DR, Tao, YZ, Godwin, ID, Henzell, RG, Cooper, M and McIntyre, CL (1998) Loss of genetic diversity associated with selection for resistance to sorghum midge in Australian sorghum. Euphytica 102: 1–7.CrossRefGoogle Scholar
Jusu, MS (1999) Management of genetic variability in rice (Oryza sativa L. and O. glaberrima Steud.) by breeders and farmers in Sierra Leone. Wageningen: Wageningen Universiteit, p. 198.Google Scholar
Kebebew, F, Tsehaye, Y and McNeilly, T (2001) Diversity of durum wheat (Triticum durum Desf.) at in situ conservation sites in North Shewa and Bale, Ethiopia. Journal of Agricultural Science 136: 383–392.CrossRefGoogle Scholar
Khlestkina, EK, Huang, XQ, Quenum, FJB, Chebotar, S, Roder, MS and Borner, A (2004) Genetic diversity in cultivated plants – loss or stability? Theoretical and Applied Genetics 108: 1466–1472.CrossRefGoogle ScholarPubMed
Kik, C, Samoylov, AM, Verbeek, WHJ, Van Raamsdonk, LWD and Mitochondrial, DNA (1997) variation and crossability of leek (Allium porrum) and its wild relatives from the Allium ampeloprasum complex. Theoretical and Applied Genetics 94: 465–471.CrossRefGoogle Scholar
Kochert, G, Stalker, HT, Gimenes, M, Galgaro, L, Lopes, CR and Moore, K (1996) RFLP and cytogenetic evidence on the origin and evolution of allotetraploid domesticated peanut, Arachis hypogaea (Leguminosae). American Journal of Botany 83: 1282–1291.CrossRefGoogle Scholar
Kolodinska Brantestam, A, von Bothmer, R, Dayteg, C, Rashal, I, Tuvesson, S and Weibull, J (2004) Inter simple sequence repeat analysis of genetic diversity and relationships in cultivated barley of Nordic and Baltic origin. Hereditas 141: 186–192.CrossRefGoogle ScholarPubMed
Kurosaki, T (2003) Specialization and diversification in agricultural transformation: the case of West Punjab,1903–92. American Journal of Agricultural Economics 85: 372–386.CrossRefGoogle Scholar
Landis, DA, Gardiner, MM, van der Werf, W and Swinton, SM (2008) Increasing corn for biofuel production reduces biocontrol in agricultural landscapes. Proceedings of the National Academy of Sciences of the United States of America 105: 20552–20557.CrossRefGoogle ScholarPubMed
Le Clerc, V, Cadot, V, Canadas, M, Lallemand, J, Guerin, D and Boulineau, F (2006) Indicators to assess temporal genetic diversity in the French Catalogue: no losses for maize and peas. Theoretical and Applied Genetics 113: 1197–1209.CrossRefGoogle ScholarPubMed
Lelley, T, Stachel, M, Grausgruber, H and Vollmann, J (2000) Analysis of relationships between Aegilops tauschii and the D genome of wheat utilizing microsatellites. Genome 43: 661–668.CrossRefGoogle Scholar
Levings, CS (1990) The Texas cytoplasm of maize: cytoplasmic male sterility and disease susceptibility. Science 250: 942–947.CrossRefGoogle ScholarPubMed
Lopez, PB (1994) A new plant disease: uniformity. CERES 26: 41–47.Google Scholar
Louette, D and Smale, M (2000) Farmers' seed selection practices and traditional maize varieties in Cuzalapa, Mexico. Euphytica 113: 25–41.CrossRefGoogle Scholar
Malysheva-Otto, L, Ganal, MW, Law, JR, Reeves, JC and Roder, MS (2007) Temporal trends of genetic diversity in European barley cultivars (Hordeum vulgare L.). Molecular Breeding 20: 309–322.CrossRefGoogle Scholar
Manifesto, MM, Schlatter, AR, Hopp, HE, Suarez, EY and Dubcovsky, J (2001) Quantitative evaluation of genetic diversity in wheat germplasm using molecular markers. Crop Science 41: 682–690.CrossRefGoogle Scholar
Maredia, MK, Byerlee, D and Pee, P (2000) Impacts of food crop improvement research: evidence from sub-Saharan Africa. Food Policy 25: 531–559.CrossRefGoogle Scholar
Martos, V, Royo, C, Rharrabti, Y and del Moral, LFG (2005) Using AFLPs to determine phylogenetic relationships and genetic erosion in durum wheat cultivars released in Italy and Spain throughout the 20th century. Field Crops Research 91: 107–116.CrossRefGoogle Scholar
Martynov, SP, Dobrotvorskaya, TV and Pukhalskiy, VA (2005) Analysis of genetic diversity of spring durum wheat (Triticum durum Desf.) cultivars released in Russia in 1929–2004. Russian Journal of Genetics 41: 1113–1122.CrossRefGoogle ScholarPubMed
Martynov, SP, Dobrotvorskaya, TV and Pukhalskiy, VA (2006) Dynamics of genetic diversity in winter common wheat Triticum aestivum L. cultivars released in Russia from 1929 to 2005. Russian Journal of Genetics 42: 1137–1147.CrossRefGoogle ScholarPubMed
Maughan, PJ, Saghai Maroof, MA, Buss, GR and Huestis, GM (1996) Amplified fragment length polymorphism (AFLP) in soybean: species diversity, inheritance, and near-isogenic line analysis. Theoretical and Applied Genetics 93: 392–401.CrossRefGoogle ScholarPubMed
Nabhan, GP (2007) Agrobiodiversity change in a Saharan desert oasis, 1919–2006: historic shifts in Tasiwit (Berber) and Bedouin crop inventories of Siwa, Egypt. Economic Botany 61: 31–43.CrossRefGoogle Scholar
Negash, A, Tsegaye, A, van Treuren, R and Visser, B (2002) AFLP analysis of enset clonal diversity in south and southwestern Ethiopia for conservation. Crop Science 42: 1105–1111.CrossRefGoogle Scholar
Nei, M (1973) Analysis of gene diversity in subdivided populations. Proceedings of the National Academy of Sciences of the United States of America 70: 3321–3323.CrossRefGoogle ScholarPubMed
Nersting, LG, Andersen, SB, von Bothmer, R, Gullord, M and Jorgensen, RB (2006) Morphological and molecular diversity of Nordic oat through one hundred years of breeding. Euphytica 150: 327–337.CrossRefGoogle Scholar
Ochoa, C (1975) Potato collecting expeditions in Chile, Bolivia and Peru, and the genetic erosion of indigenous cultivars. In: Frankel, OH and Hawkes, JG (eds) Crop Genetic Resources for Today and Tomorrow. Cambridge: Cambridge University Press, pp. 167–173.Google Scholar
Olsen, KM and Purugganan, MD (2002) Molecular evidence on the origin and evolution of glutinous rice. Genetics 162: 941–950.CrossRefGoogle ScholarPubMed
Palaisa, K, Morgante, M, Tingey, S and Rafalski, A (2004) Long-range patterns of diversity and linkage disequilibrium surrounding the maize Y1 gene are indicative of an asymmetric selective sweep. Proceedings of the National Academy of Sciences of the United States of America 101: 9885–9890.CrossRefGoogle ScholarPubMed
Palladino, P (1990) The political economy of applied research: plant breeding in Great Britain, 1910–1940. Minerva 28: 446–468.CrossRefGoogle Scholar
Parzies, HK, Spoor, W and Ennos, RA (2000) Genetic diversity of barley landrace accessions (Hordeum vulgare ssp vulgare) conserved for different lengths of time in ex situ gene banks. Heredity 84: 476–486.CrossRefGoogle ScholarPubMed
Peng, JR, Richards, DE, Hartley, NM, Murphy, GP, Devos, KM, Flintham, JE, Beales, J, Fish, LJ, Worland, AJ, Pelica, F, Sudhakar, D, Christou, P, Snape, JW, Gale, MD and Harberd, NP (1999) ‘Green revolution’ genes encode mutant gibberellin response modulators. Nature 400: 256–261.CrossRefGoogle ScholarPubMed
Peroni, N and Hanazaki, N (2002) Current and lost diversity of cultivated varieties, especially cassava, under swidden cultivation systems in the Brazilian Atlantic Forest. Agriculture Ecosystems & Environment 92: 171–183.CrossRefGoogle Scholar
Pistorius, R (1997) Scientists, Plants and Politics – A History of The Plant Genetic Resources Movement. Rome: International Plant Genetic Resources Institute.Google Scholar
Portis, E, Acquadro, A, Comino, C and Lanteri, S (2004) Effect of farmers' seed selection on genetic variation of a landrace population of pepper (Capsicum annuum L.), grown in North-West Italy. Genetic Resources and Crop Evolution 51: 581–590.CrossRefGoogle Scholar
Prashanth, SR, Parani, M, Mohanty, BP, Talame, V, Tuberosa, R and Parida, A (2002) Genetic diversity in cultivars and landraces of Oryza sativa subsp indica as revealed by AFLP markers. Genome 45: 451–459.CrossRefGoogle ScholarPubMed
Pressoir, G and Berthaud, J (2004) Patterns of population structure in maize landraces from the Central Valleys of Oaxaca in Mexico. Heredity 92: 88–94.CrossRefGoogle ScholarPubMed
Purseglove, JW (1974) Tropical Crops, Dicotyledons. Harlow: Longman.Google Scholar
Qi, Y, Zhang, D, Zhang, H, Wang, M, Sun, J, Wei, X, Qiu, Z, Tang, S, Cao, Y, Wang, X and Li, Z (2006) Genetic diversity of rice cultivars (Oryza sativa L.) in China and the temporal trends in recent fifty years. Chinese Science Bulletin 51: 681–688.CrossRefGoogle Scholar
Rasmusson, DC and Phillips, RL (1997) Plant breeding progress and genetic diversity from de novo variation and elevated epistasis. Crop Science 37: 303–310.CrossRefGoogle Scholar
Reif, JC, Hamrit, S, Heckenberger, M, Schipprack, W, Maurer, HP, Bohn, M and Melchinger, AE (2005a) Trends in genetic diversity among European maize cultivars and their parental components during the past 50 years. Theoretical and Applied Genetics 111: 838–845.CrossRefGoogle ScholarPubMed
Reif, JC, Zhang, P, Dreisigacker, S, Warburton, ML, van Ginkel, M, Hoisington, D, Bohn, M and Melchinger, AE (2005b) Wheat genetic diversity trends during domestication and breeding. Theoretical and Applied Genetics 110: 859–864.CrossRefGoogle ScholarPubMed
Richards, R and Ruivenkamp, G (1997) Seeds and Survival: Crop Genetic Resources in War and Reconstruction in Africa. Rome: International Plant Genetic Resources Institute.Google Scholar
Roussel, V, Koenig, J, Beckert, M and Balfourier, F (2004) Molecular diversity in French bread wheat accessions related to temporal trends and breeding programmes. Theoretical and Applied Genetics 108: 920–930.CrossRefGoogle ScholarPubMed
Roussel, V, Leisova, L, Exbrayat, F, Stehno, Z and Balfourier, F (2005) SSR allelic diversity changes in 480 European bread wheat varieties released from 1840 to 2000. Theoretical and Applied Genetics 111: 162–170.CrossRefGoogle ScholarPubMed
Scholten, M, Maxted, N and Ford-Lloyd, BV (2006) UK National Inventory of Plant Genetic Resources for Food and Agriculture. Birmingham: School of Biosciences, University of Birmingham, p. 86.Google Scholar
Smale, M (1997) The green revolution and wheat genetic diversity: Some unfounded assumptions. World Development 25: 1257–1269.CrossRefGoogle Scholar
Smale, M, Reynolds, MP, Warburton, M, Skovmand, B, Trethowan, R, Singh, RP, Ortiz-Monasterio, I and Crossa, J (2002) Dimensions of diversity in modern spring bread wheat in developing countries from 1965. Crop Science 42: 1766–1779.CrossRefGoogle Scholar
Soleimani, VD, Baum, BR and Johnson, DA (2002) AFLP and pedigree-based genetic diversity estimates in modern cultivars of durum wheat (Triticum turgidum L. subsp durum (Desf.) Husn.). Theoretical and Applied Genetics 104: 350–357.CrossRefGoogle ScholarPubMed
Souza, E and Sorrells, ME (1989) Pedigree analysis of North-American oat cultivars released from 1951 to 1985. Crop Science 29: 595–601.CrossRefGoogle Scholar
Sperling, L (2001) The effect of the civil war on Rwanda's bean seed systems and unusual bean diversity. Biodiversity and Conservation 10: 989–1009.CrossRefGoogle Scholar
Tanksley, SD and McCouch, SR (1997) Seed banks and molecular maps: unlocking genetic potential from the wild. Science 277: 1063–1066.CrossRefGoogle ScholarPubMed
Tenaillon, MI, U'Ren, J, Tenaillon, O and Gaut, BS (2004) Selection versus demography: A multilocus investigation of the domestication process in maize. Molecular Biology and Evolution 21: 1214–1225.CrossRefGoogle ScholarPubMed
Theissen, G (2002) Key genes of crop domestication and breeding: molecular analyses. Pogress in Botany 63: 189–203.CrossRefGoogle Scholar
Thomson, MJ, Septiningsih, EM, Suwardjo, F, Santoso, TJ, Silitonga, TS and McCouch, SR (2007) Genetic diversity analysis of traditional and improved Indonesian rice (Oryza sativa L.) germplasm using microsatellite markers. Theoretical and Applied Genetics 114: 559–568.CrossRefGoogle ScholarPubMed
Tian, QZ, Zhou, RH and Jia, JZ (2005) Genetic diversity trend of common wheat (Triticum aestivum L.) in China revealed with AFLP markers. Genetic Resources and Crop Evolution 52: 325–331.CrossRefGoogle Scholar
Tsegaye, B and Berg, T (2007) Genetic erosion of Ethiopian tetraploid wheat landraces in Eastern Shewa, Central Ethiopia. Genetic Resources and Crop Evolution 54: 715–726.CrossRefGoogle Scholar
van Zanden, JL (1991) The first green revolution: the growth of production and productivity in European agriculture, 1870–1914. The Economic History Review 44: 215–239.CrossRefGoogle Scholar
van de Wouw, M, van Hintum, T, Kik, C, van Treuren, R and Visser, B (submitted) Genetic diversity trends in 20th century crop cultivars- a meta analysis. Theoretical and Applied Genetics.Google Scholar
van der Meer, WC and van den Ban, PA (1956) Bijzondere plantenteelt. Zwolle: Tjeenk Willink.Google Scholar
Warburton, ML, Crossa, J, Franco, J, Kazi, M, Trethowan, R, Rajaram, S, Pfeiffer, W, Zhang, P, Dreisigacker, S and van Ginkel, M (2006) Bringing wild relatives back into the family: recovering genetic diversity in CIMMYT improved wheat germplasm. Euphytica 149: 289–301.CrossRefGoogle Scholar
White, J, Law, JR, MacKay, I, Chalmers, KJ, Smith, JSC, Kilian, A and Powell, W (2008) The genetic diversity of UK, US and Australian cultivars of Triticum aestivum measured by DArT markers and considered by genome. Theoretical and Applied Genetics 116: 439–453.CrossRefGoogle ScholarPubMed
Willemen, L, Scheldeman, X, Cabellos, VS, Salazar, SR and Guarino, L (2007) Spatial patterns of diversity and genetic erosion of traditional cassava (Manihot esculenta Crantz) in the Peruvian Amazon: An evaluation of socio-economic and environmental indicators. Genetic Resources and Crop Evolution 54: 1599–1612.CrossRefGoogle Scholar
Yang, GP, Maroof, MAS, Xu, CG, Zhang, QF and Biyashev, RM (1994) Comparative-analysis of aicrosatellite DNA polymorphism in landraces and cultivars of rice. Molecular & General Genetics 245: 187–194.CrossRefGoogle ScholarPubMed
Zeder, MA, Emshwiller, E, Smith, BD and Bradley, DG (2006) Documenting domestication: the intersection of genetics and archaeology. Trends in Genetics 22: 139–155.CrossRefGoogle ScholarPubMed