Abstract
This investigation was conducted to assess changes in the genetic structure of two varieties of two species of annual Brassica. Seeds of B. napus cv. “Topas” and B. rapa “Broccoletto” were sent to nine research institutes in different geographical areas of Europe for regeneration. The multiplied material was sent back after one year of regeneration and analysed electrophoretically. The original populations of each species and their multiplied samples were stained for 12 different enzymes, of which 4 were found to be polymorphic (DIA, SKD, GPI and PER). It was possible to detect considerable differences in isozyme patterns in B. napus and allelic frequencies in B. rapa, both within and between populations. When the original population was compared with the regenerated samples, the Chi-square homogeneity test for all pairwise comparisons revealed distinctness with a 99% probability for B. napus and 95% probability for B. rapa with one or more of the enzyme systems examined. Furthermore, the average of gene diversity analysis (Nei, 1973) revealed that some regenerated populations have less while others have increased genetic variation compared with the original population. These observations indicated that the frequencies were non-random and considerable shifts in genetic diversity have occurred during multiplication. In addition, different regeneration procedures have caused the fixation of certain alleles.
Similar content being viewed by others
References
Arús, P., C.R. Shields & T.J. Orton, 1985. Application of isozyme electrophoresis for purity testing and cultivar identification of F1 hybrids of Brassica oleracea. Euphytica 34: 651–657.
Arús, P., J.J. Baladrón & A. Ordás, 1987. Species identification of cultivated Brassicas with isozymes electrophoresis. Eucarpia Cruciferae Newsletter 12: 26–27
Ayala, F.J. & J.A. Kiger, 1984. Modern Genetics. The Benjamin/ Cummings Publishing Company, Inc. California.
Becker, H.C., C. Damgaard & B. Karlsson, 1992. Environmental variation for outcrossing rate in rapeseed (Brassica napus). Theor. Appl. Genet. 84: 303–306.
Breese, E.L., 1989. Regeneration and multiplication of germplasm resources in seed genebanks: the scientific background. International Board for Plant Genetic Resources (IBPGR).
Chen, B.Y., W.K. Heneen & V. Simonsen, 1989. Comparative and genetic studies of isozymes in resynthesized and cultivated Brassica napus L., B. rapa L. and B. alboglabra Bailey. Theor. Appl. Genet. 77: 673–679.
Chen, B.Y., W.K. Heneen & V. Simonsen, 1990. Genetics of isozyme loci in Brassica rapa L. and in the progeny of a trigenomic hybrid between B. napus L. and B. rapa L. Genome 33: 433–440.
Coulhart, M.B. & K.E. Denford, 1982. Isozymes as genetic markers in Brassica. Eucarpia Cruciferae Newsletter 4: 18–20.
Gustafsson, M., C. Gómez-Campo & A. Zamanis, 1983. Report from the first Brassica Germplasm exploration in Greece 1982. J. Swed. Seed Assoc. 93: 151–160.
Gustafsson, M., C. Gómez-Campo & A. Zamanis, 1985. Germplasm conservation of wild Mediterranean Brassica species. Collecting missions in 1993. J. Seed. Seed Assoc. 95: 137–143.
IBPGR. 1993. Report of a working group on Brassica (First meeting, 1991). European Cooperative Programme for Crop Genetic Resources Networks (ECP/GR). IBPGR, Rome.
IUBNC, 1984. International Union of Biochemistry, Nomenclature Committee. Enzyme Nomenclature 1984. Academic press, Orlando, Florida.
Iwasaki, F., 1983. Zymogram analysis in Brassica species. Jpn. J. Breed. 33: 171–177.
Lewontin, R.C. & J. Felsenstein, 1965. The robustness of homogeneity in 2 x n tables. Biometrics 21: 19–21.
MacGrath, J.M. & C.F. Quiros, 1992. Genetic diversity at isozymes and RFLP loci in Brassica rapa as related to crop type and geographical origin. Theor. Appl. Genet. 83: 783–790.
Mündges-Christmann, H. & W. K¨ohler, 1990. Enzymmarker zur Bestimmung der Fremdbefruchtungsrate und der genetischen Struktur bei Winterraps. Mitt Ges Pflanzenbauwiss 3: 163–166.
Nei, M., 1973. Analysis of gene diversity in subdivided populations. Proc. Natl. Acad. Sci. U.S.A. 70: 3321–3323.
Simonssen, V. & W.K. Heneen, 1995b. Inheritance of isozymes in Brassica rapa and genetic divergence among different species of Brassiceae. Theor. Appl. Genet.91: 353–360.
Soltis, D.E., C.H. Haufler, D.C. Darrow & G.J. Gastony, 1983. Starch gel electrophoresis of ferns: a compilation of grinding buffers, gel and electrode buffers, and staining schedules. Am. Fern J. 73: 9–27.
Thorpe, M.L., L.H. Duke & W.D. Beversdorf, 1987. Procedures for the detection of isozymes of rapeseed (Brassica napus and B. rapa) by starch gel electrophoresis. Department of Crop Science. Technical Bulletin TB OAC 887. University of Guelph, Ontario, Canada.
Vallejos, C.E., 1983. Enzyme staining activity. In: S.D. Tanksley & T.J. Orton (Eds.). Isozymes in Plant Genetics and Breeding, Part A, pp. 469–516. Elsevier Science Publisher B.V., Amsterdam.
Wendel, J.F. & N.F. Weeden, 1989. Visualization and interpretation of plant isozymes. In: Isozymes in plant biology, pp. 30–31. Chapman and Hall, London.
Wills, A.B., S. K. Fyfe & E.V. Wiseman, 1979. Testing F1 hybrids of Brassica oleracea for sibs by seed isoenzyme analysis. Ann. Appl. biol. 91: 263–270.
U, N., 1935. Genome-analysis in Brassica with special reference to the experimental formation of B. napus and its peculiar mode of fertilization. Jpn. J. Bot. 7: 389–452.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Diaz, O., Gustafsson, M. & Astley, D. Effect of regeneration procedures on genetic diversity in Brassica napus and B. rapa as estimated by isozyme analysis. Genetic Resources and Crop Evolution 44, 523–532 (1997). https://doi.org/10.1023/A:1008668624948
Issue Date:
DOI: https://doi.org/10.1023/A:1008668624948