Summary
To identify the principal characters which account for the major variation among yellow yams, Dioscorea cayenensis Lam., for use in routine groupings, 20 accessions were studied using principal component analysis (PCA) with 49 characters. Based on PCA, six characters were chosen for constructing the metroglyph, whose groupings of accessions highly corresponded with those indicated by a PCA ordination on axes I, II and III. The main vegetative characters that distinguish between yellow yam accessions were: leaf retension in October, mean leaf area, size of tuber crown, leaf virus infection, plant leafiness, and fresh tuber yield. However, some accessions consistently failed to flower and can thus be easily differentiated.
The study also showed that some accessions seemed to be duplicates while the grouping of the more typical yellow yams was more obvious from the metroglyph than in the PCA ordination.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Akoroda, M. O. & H. R. Chheda, 1982. Agro-botany and species relations of Guinea yams. (Manuscript in review).
Alexander, J. & D. G. Coursey, 1969. The origins of yam cultivation. In: Ucko, P. J. & G. W. Dimbleby (Eds), The domestication and exploitation of plants and animals, Gerald Duckworth, London.
Anderson, E., 1957. A semi-graphical method for the analysis of complex problems. Proc. Nat. Acad. Sci. 43: 923–927.
Bhatt, G. M., 1970. Multivariate analysis approach to selelction of parents for hybridisation aiming at yield improvement in self-pollinated crops. Aust. J. Agric. Res. 21: 1–7.
Boyce, A. J., 1969. Mapping diversity: a comparative study of some numerical methods. In: Cole, A. J. (Ed.), Numerical taxonomy, Academy Press, London.
Clifford, H. T. & W. Stephenson, 1975. An introduction to numerical classification. Academic Press, London.
Eastwood, R. B. & W. M. Steele, 1978. The conservation of yam germplasm in West Africa. Plant foods for man 2: 153–158.
Edye, L. A., W. T. Williams & A. J. Pritchard, 1970. A numerical analysis of variation patterns in Australian introductions of Glycine wightii (G. javanica). Aus. J. Agric. Res. 21: 57–69.
Harman, H. H., 1967. Modern factor analysis, 2nd Ed. University of Chicago Press, Chicago.
Hatheway, W. H., 1962. A weighted hybrid index. Evolution 26: 1–10.
IITA, 1974. Annual Report of 1974. International Institute of Tropical Agriculture, Ibadan, Nigeria.
Kay, D. E., 1973. Root crops. Crop and Product Digest No. 2, Tropical Products Institute, London.
Lawton, J. R. S., 1967. A key to the Dioscorea species in Nigeria. J. West Afr. Sci. Assoc. 12: 3–9.
Loomis, R. S. & W. A. Williams, 1972. Plant conformation and yield. In: Induced mutations and plant improvement. FAO/IAEA, Vienna: 13–25.
Martin, F. W. & A. M. Rhodes, 1977. Intraspecific classification of Dioscorea alata. Trop. Agric. (Trinidad) 54: 1–13.
Martin, F. W. & A. M. Rhodes, 1978. The relationship of Dioscorea cayenensis and D. rotundata. Trop. Agric. (Trinidad) 55: 193–206.
Rhodes, A. M. & F. W. Martin, 1972. Multivariate studies of variation in yams (Dioscorea alata L.). J. Amer. Soc. Hort. Sci. 97: 685–688.
Sadik, S. & O. U. Okereke, 1975. Flowering, pollen grain germination, fruiting, seed germination and seedling development of white yam, Dioscorea rotundata Poir. Ann. Bot. 39: 597–604.
Sneath, R. H. A. & R. R. Sokal, 1973. Numerical taxonomy. Freeman Co., San Francisco.
Waitt, A. W., 1961. Review of yam research in Nigeria 1920–1961. Fed. Dept. Agric. Res. Memo. No. 31. Lagos.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Akoroda, M.O. Principal component analysis and metroglyph of variation among nigerian yellow yams. Euphytica 32, 565–573 (1983). https://doi.org/10.1007/BF00021469
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00021469