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ARS Home » Pacific West Area » Davis, California » Nat'l Clonal Germplasm Rep - Tree Fruit & Nut Crops & Grapes » Research » Publications at this Location » Publication #231289
Title: Genetic variability in Macadamia

Author
item Aradhya, Mallikarjuna
item LIANA, Y. - UNIV OF HAWAII - HORT
item Zee, Francis
item MANSHARDT, R. - UNIV OF HAWAII - HORT

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Popular Publication
Publication Acceptance Date: 6/10/1997
Publication Date: N/A
Citation: Aradhya, M.K., Liana, Y., Zee, F.T., Manshardt, R.M. 1998. Genetic variability in Macadamia. Genetic Resources and Crop Evolution., 45: 19-32.

Interpretive Summary: A genetic variability analysis involving 45 accessions of Macadamia including four species, M. integrifolia, M. tetraphylla, M. ternifolia, and M. hildebrandii and a wild relative, Hicksbeachia pinnatifolia was performed usingeight enzyme systems encoded by 16 loci (Gpi-1 and 2, Idh-1 and 2, Lap, Mdh-1, 2, and 3, 6Pgd-2, Pgm-2 and 3, Tpi-1 and 2, Ugpp-1, 2, and 3). Forty-three accessions possessed distinct isozyme fingerprints indicating a high level of genetic variation. Examination of multivariate relationships among accessions using a cluster analysis resulted in the identification of four clusters, two of which contained one accession each representing H. pinnatifolia and M. hildebrandii. All Hawaiian cultivars were included in two sub-clusters within the largest cluster, which encompassed all the M. integrifolia and three M. ternifolia accessions, suggesting that: (1) the Hawaiian cultivars must have originated from at least two genetically diverse ancestral populations and (2) M. ternifolia may be a conspecific variant of M. integrifolia. Macadamia tetraphylla has diverged marginally from the M. integrifolia and M. ternifolia complex suggesting that these taxa represent a species complex. The different measures of genetic variability such as mean number of alleles per locus, polymorphic index, and observed and expected levels of heterozygosity, indicated significant levels of genetic variation in the Macadamia collection.

Technical Abstract: A genetic variability analysis involving 45 accessions of Macadamia including four species, M. integrifolia, M. tetraphylla, M. ternifolia, and M. hildebrandii and a wild relative, Hicksbeachia pinnatifolia was performed usingeight enzyme systems encoded by 16 loci (Gpi-1 and 2, Idh-1 and 2, Lap, Mdh-1, 2, and 3, 6Pgd-2, Pgm-2 and 3, Tpi-1 and 2, Ugpp-1, 2, and 3). Forty-three accessions possessed distinct isozyme fingerprints indicating a high level of genetic variation. Examination of multivariate relationships among accessions using a cluster analysis resulted in the identification of four clusters, two of which contained one accession each representing H. pinnatifolia and M. hildebrandii. All Hawaiian cultivars were included in two sub-clusters within the largest cluster, which encompassed all the M. integrifolia and three M. ternifolia accessions, suggesting that: (1) the Hawaiian cultivars must have originated from at least two genetically diverse ancestral populations and (2) M. ternifolia may be a conspecific variant of M. integrifolia. Macadamia tetraphylla has diverged marginally from the M. integrifolia and M. ternifolia complex suggesting that these taxa represent a species complex. The different measures of genetic variability such as mean number of alleles per locus, polymorphic index, and observed and expected levels of heterozygosity, indicated significant levels of genetic variation in the Macadamia collection.