Summary
The first explorations for the collection of genetic resources of crop plants took place in areas designated as centers of origin. Later, important characters were found to be present in areas other than those indicated by Vavilov. Hence collection missions were extended to cover other areas in addition to the “centers of diversity” with different ecogeography and agromorphological features. Collecting activities were aimed not only at providing germplasm for immediate use in breeding but also at conserving genetic variation for future contingencies. The analysis of the collected material has revealed the complex nature, amount and distribution of genetic variation present in natural populations as well as in landraces, old varieties and primitive forms. The study of variation for characters from different regions indicated that it is possible to select certain characters for detecting variability in the populations and establishing the minimum number of genotypes to be sampled. A minimum number of 20–130 plants per sample, depending on the crop, is recommended in order to capture 95% of the total variation in the field. However, it has been emphasized that the number of different populations sampled rather than the sample size per population determines the overall efficiency of a collection. The findings reported allow better utilization of the collected material and formulation of optimal and cost-effective sampling strategies for the future.
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References
Adary, A.M., 1978. Genetic Variation in Landraces of Durum Wheat and its Value in Durum Wheat Improvement. Ph.D. Thesis, Univ. of California, Davis, Calif.
Allard, R.W., 1965. Genetic systems associated with colonizing ability in predominantly self-pollinated species. In: H.G. Baker & G.L. Stebbins (Eds), The Genetics of Colonizing Species, pp. 49–75, Academic Press, New York.
Allard, R.W., 1970. Population structure and sampling methods. In: O.H. Frankel & E. Bennett (Eds), Genetic Resources in Plants-their Exploration and Conservation, pp. 97–107, Blackwell, Oxford.
Allard, R.W., S.K. Jain & P.L. Workman, 1966. The genetics of inbreeding populations. Adv. Genet. 14: 55–131.
Allard, R.W. & J. Adams, 1969. Population studies in selfpollinated species. Intergenotypic competition and population structure in barley and wheat. American Naturalist 103: 621–645.
Allard, R.W., A.L. Kahler & B.S. Weir, 1971. Isozyme polymorphisms in barley populations. In: R.A. Nilan, (Ed.), Barley Genetics II, pp. 1–13, Wash. State Univ. Press, Pullman.
Allard, R.W., G.R. Babbel, M.T. Clegg & A.L. Kahler, 1972. Evidence for coadaptation in Avena barbata. Proc. Natl. Acad. Sci. USA. 69: 3034–3048.
Ashri, A., 1973. Divergence and evolution in the safflower genus Carthamus L. Final research report USDA PL 480 Project, Jerusalem.
Benjasil, V., 1968. Effects of Mass Selection for Quantitative Traits in Sorghum. Ph.D. Thesis, Univ. of California, Davis, Calif.
Bennett, E., 1970. Tactics of plant exploration. In: O.H. Frankel & E. Bennett (Eds), Genetic Resources in Plantstheir Exploration and Conservation, pp. 157–188, Blackwell, Oxford.
Bogyo, T.P., E. Porceddu & P. Perrino, 1980. Analysis of sampling strategies for collecting genetic material. Economic Botany 34: 160–174.
Bonciarelli, F., 1961. Studio comparato delle popolazioni umbre di mais. Maydica 6: 35–61 [In Italian].
Bradshaw, A.D., 1975. Population structure and the effects of isolation and selection. In: O.H. Frankel & J.G. Hawkes (Eds), Crop Genetic Resources for Today and Tomorrow, pp. 37–52, Cambridge University Press, Cambridge.
Brandolini, A., 1970. Maize. In: O.H. Frankel & E. Bennett (Eds), Gentic resources in Plants-their Exploration and Conservation, pp. 273–310, Blackwell, Oxford.
Brown, A.H.D., 1978. Isozymes, plant population, genetic structure and genetic conservation. Theor. Appl. Genet. 52: 145–157.
Brown, A.H.D., E. Nevo & D. Zohary, 1977. Association of alleles at esterase loci in wild barley Hordeum spontaneum. Nature 268: 430–431.
Ceccarelli, S. & E. Ottaviano, 1967. Analisi genetica della variabilita continua in Chelidonium majus L. Rend. Classe di Scienze B, 101: 477–497.
Chang, T.T., 1985. Collection of crop germplasm. Iowa State J. Res. 59: 349–364.
Clegg, M.T., R.W. Allard & A.L. Kahler, 1972. Is the gene the unit of selection? Evidence from two experimental populations. Proc. Nat. Acad. Sci., USA. 69: 2447–2478.
Cochran, W.G., 1963. Sampling Techniques. Second edition. John Wiley, New York.
Creech, J.L. & L.P. Reitz, 1971. Plant germ plasm now and for tomorrow. Adv. Agronomy 23: 1–49.
Damania, A.B., 1987. Sampling cereal diversity in Morocco. Plant Genetic Resources Newslt. 72: 29–30.
Damania, A.B., 1989a. Crop Genetic Resources Sampling: A Training Handbook for Germplasm Collection. ICARDA, Aleppo.
Damania, A.B., 1989b. Genetic resources of wild relatives in cereal crops. I. Germplasm sampling strategy. Rachis 8(1): 8–10.
Damania, A.B. & E. Porceddu, 1983. Variation in landraces of Turgidum and bread wheats and sampling strategies for collecting wheat genetic resources. In: S. Sakamoto (Ed.), Proc. Sixth Intl. Wheat Genetics Symp., pp. 123–136, Plant Germplasm Institute, Kyoto.
Debouck, D.G., 1988. Phaseolus germplasm exploration. In: P. Gepts (Ed.), Genetic Resources of Phaseolus Beans: their Maintenance, Domestication, Evolution, and Utilization, pp. 3–29, Kluwer, Dordrecht.
Dempster, E.R., 1955. Maintenance of genetic heterogeneity. Cold Spring Harbor Symp. Quant. Biol. 20: 25–32.
Drayner, J.M., 1959. Self and cross-fertility in field beans (Vicia faba L.). J. Agric. Sci. Cambridge 53: 387–402.
Elings, A., 1991. Durum wheat landraces from Syria. II. Patterns of variation. Euphytica 54: 231–243.
Frost, S., G. Holm & S. Asker, 1975. Flavonoid patterns and the phylogeny of barley. Hereditas 79: 133–142.
Harding, J., R.W. Allard & D.G. Smeltzer, 1966. Population studies in predominantly self-pollinated species. IX. Frequency dependent selection in Phaseolus lunatus. Proc. Nat. Acad. Sci., USA. 56: 99–104.
Harlan, J.R., 1970. Evolution of cultivated plants. In: O.H. Frankel & E. Bennett (Eds), Genetic Resources in Plants—their Exploration and Conservation, pp. 19–32, Blackwell, Oxford.
Harlan, J.R., 1971. Agricultural origins: centers and noncenters. Science 174: 468–474.
Harlan, J.R., 1975. Seed crops. In: O.H. Frankel & J.G. Hawkes (Eds), Crop Genetic Resources for Today and Tomorrow, pp. 111–116, Cambridge University Press, Cambridge.
Harlan, J.R., 1986. Plant domestication: diffuse origin and diffusion. In: C. Barigozzi (Ed.), The Origin and Domestication of Cultivated Plants, pp. 21–34, Elsevier, Amsterdam.
Hayman, B.I., 1953. Mixed selling and random mating when homozygotes are at disadvantage. Heredity 7: 185–192.
Hartley, W., 1963. The phytogeographic basis of pasture plant introduction. Genetica Agraria 17: 135–146.
Hussaini, S.H., M.M. Goodman & D.H. Timothy, 1977. Multivariate analysis and the geographical distribution of the world collection of finger millet. Crop Science 17: 257–263.
ICARDA, 1991. Genetic Resources Unit—Annual Report for 1991. International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria.
Imam, A.G. & R.W. Allard, 1965. Population studies in predominantly self-pollinated species. VI. Genetic variability between and within natural populations of wild oats from differing habits in California. Genetics 51: 49–62.
Jain, S.K. & R.W. Allard, 1960. Population studies in predominantly self-pollinated species. I. Evidence of heterozygote advantage in a closed population of barley. Proc. Nat. Acad. Sci. USA. 46: 1371–1377.
Jain, S.K. & D.R. Marshall, 1967. Population studies in predominantly self-pollinated species. X. Variation in natural population of Avena fatua and A. barbata. American Naturalist 101: 19–33.
Jain, S.K., C.O. Qualset, G.M. Bhatt & K.K. Wu, 1975. Geographical patterns of phenotypic diversity in a world collection of Durum wheats. Crop Science 15: 700–704.
Jana, S., 1988. Collecting crop germplasm during exploration: bulk samples or individual plants? FGRC Newslt. 24: 5–7.
Jana, S. & B. S. Khangura, 1986. Conservation of diversity in bulk populations of barley (Hordeum vulgare L.). Euphytica 35: 761–776.
Johannsen, W., 1926. Elemente der Exakten Erblichkeitslehre. 3rd edition, Fisher, Jena.
Knowles, P.F., 1943. Improving an annual bromegrass, Bromus mollis L., for range purposes. J. Am. Soc. Agron. 35: 584–594.
Lafiandra, D., G.B. Polignano, A. Filippetti & E. Porceddu, 1981. Genetic variability for protein content and s-aminoacids in broad beans (Vicia faba L.). Die Kulturpflanze 29: 115–127.
Marshall, D.R. & A.H.D. Brown, A. H. D. 1975. Optimum sampling strategies in genetic conservation. In: O.H. Frankel & J.G. Hawkes (Eds), Crop genetic Resources for Today and Tomorrow, pp. 53–80, Cambridge University Press, Cambridge.
Murphy, B.R. & V. Arunachalam, 1966. The nature of divergence in relation to breeding system in some crop plants. Indian J. Genet. 26: 188–198.
Nakagahra, M., T. Akihama & K. Hayashi, 1975. Genetic and geographic cline of esterase isozymes in native rice varieties. Japan J. Genet. 50: 373–382.
Narayan, R.K.J. & A.J. Macefield, 1976. Adaptive responses and genetic divergence in a world germplasm collection of chickpea (Cicer arietinum L.). Theor. Appl. Genet. 47: 179–187.
Nevo, E., A.H.D. Brown & M. Habez, 1979. Genetic diversity and environmental associations of wild barley, Hordeum spontaneum. Evolution 33: 815–1179.
O'Donald, P., 1960. Assortative mating in a population in which two alleles are segregating. Heredity 15: 389–396.
Oka, H.I., 1975. Consideration on the population size necessary for conservation of crop germplasms. In: (Ed.), T. Matsuo, Gene Conservation-Exploration, Collection, Preservation and Utilization of Genetic Resources, pp. 57–63, University of Tokyo Press, Tokyo.
Pathak, R.S. & C.P. Bindlish, 1976. Studies on the nature of genetic divergence in upland cotton (Gossypium hirsutum L.). Z. Pflanzenzuctg. 76: 56–67.
Porceddu, E., 1976. Variation for agronomical traits in a world collection of Durum wheat. Z. Pflanzenzuchtg. 77: 314–329.
Porceddu, E., 1979. Genetic variability in durum wheat germplasm of different origins. In: Monografia IV di Genetica Agraria: 39–70.
Porceddu, E., L.M. Monti, L. Frusciante & N. Volpe, 1980. Analysis of cross-pollination in Vicia faba L. Z. Pflanzenzüchtg. 84: 313–322.
Qualset, C.O., 1968. Population structure and performance in wheat. In: K.W. Finlay & K.W. Shepherd (Eds), Proc. Third Intl. Wheat Genetics Symp., pp. 397–402, Australian Academy of Science, Canberra.
Qualset, C.O., 1975. Sampling germplasm in a center of diversity: an example of disease resistance in Ethiopian barley. In: O.H. Frankel & J.G. Hawkes (Eds), Crop Genetic Resources for Today and Tomorrow, pp. 81–96, Cambridge University Press, Cambridge.
Rao, A.R., 1977. Distribution patterns of indigenous wheat varieties in northern Pakistan. In: A. Muhammed, R. Aksel & R.C. von Borstel (Eds), Genetic Diversity in Plants, pp. 51–66, Plenum Press, New York.
Rick, C.M., R.W. Zobel & J.F. Fobes, 1974. Four peroxidase loci in red-fruited tomato species: Genetics and geographical distribution. Proc. Nat. Acad. Sci., USA. 71: 835–839.
Shutz, W.M. & S.A. Usanis, 1969. Inter-genotypic interactions in plant populations. II. Maintenance of allelic polymorphisms with frequency dependent selection and mix selfing and random mating. Genetics 61: 875–891.
Spagnoletti-Zeuli, P.-L., C. De Pace & E. Porceddu, 1984. Variation in durum wheat populations from three geographic regions. I. Material and spike characteristics. Euphytica 33: 563–575.
Vavilov, N.I., 1926. Studies on the origin of cultivated plants. Institute of Applied Plant Breeding and Botany 16: 139–248 (In Russian).
Vavilov, N.I., 1951. Phytogeographic basis of plant breeding. In: The Origin, Variation, Immunity and Breeding of Cultivated Plants. (Transl. K.S. Chester) Chronica Bot. 13: 14–54.
Weir, B.S., R.W. Allard & A.L. Kahler, 1974. Further analysis of complex allozyme polymorphisms in a barley population. Genetics 78: 911–919.
Witcombe, J.R. & M.M. Gilani, 1979. Variation in cereals from the Himalayas and the optimum strategy for sampling plant germplasm. J. Appl. Ecology 16: 633–640.
Workmann, P.L. & S.K. Jain, 1966. Zygotic selection under mixed random mating and self-fertilization: theory and problems of estimation. Genetics 54: 159–171.
Yamashita, K., 1980. Origin and dispersion of wheats with special references to peripheral diversity. Z. Pflanzenzüchtg. 84: 122–132.
Yonezawa, K., 1985. A definition of the optimal allocation of effort in conservation of plant genetic resources-with application to sample size determination for field collection. Euphytica 34: 345–354.
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Porceddu, E., Damania, A.B. Sampling variation in genetic resources of seed crops: a review. Genet Resour Crop Evol 39, 39–49 (1992). https://doi.org/10.1007/BF00052652
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DOI: https://doi.org/10.1007/BF00052652