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ARS Home » Southeast Area » Miami, Florida » Subtropical Horticulture Research » Research » Publications at this Location » Publication #129862
Title: ANALYSIS OF GENETIC DIVERSITY AND POPULATION STRUCTURE WITHIN FLORIDA COCONUT (COCOS NUCIFERA L.) GERMPLASM USING MICORSATELLITE DNA, WITH SPECIAL EMPHASIS ON THE FIJI DWARF CULTIVAR

Author
item Meerow, Alan
item WISSER, R. - CORNELL UNIVERSITY
item Brown, James
item KUHN, DAVID - FLORIDA INT'L UNIVERSITY
item Schnell Ii, Raymond
item BROSCHAT, T. - UNIVERSITY OF FLORIDA

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/2002
Publication Date: 10/24/2002
Citation: Meerow, A.W., Wisser, R.J., Brown, J.S., Kuhn, D.N., Schnell II, R.J., Broschat, T.K. 2002. Analysis of genetic diversity and population structure within Florida coconut (Cocos nucifera L.) germplasm using micorsatellite DNA, with special emphasis on the Fiji Dwarf cultivar. Journal of Theoretical and Applied Genetics. 106:715-726.

Interpretive Summary: Using fifteen DNA markers, we analyzed genetic variation within Cocos nucifera germplasm collections at two locations in south Florida, representing eight varieties. The markers were also used in to estimate the parents of progeny of the 'Fiji Dwarf' variety at both locations. The markers uniquely identified 83 of the 110 individual palms. 'Fiji Dwarf', 'Malayan Dwarf', 'Green Nino', and 'Red Spicata' cultivars are all resolved by the 15b markers, while the tall varieties ('Atlantic Tall', 'Panama Tall') form two aggregates. The highest gene diversity was found in the talls, and the lowest in the 'Malayan Dwarf'. After the tall coconuts, the 'Fiji Dwarf' was most genetically diverse and had the largest number of unique alleles of any variety. Genetic similarity is highest among the 'Malayan Dwarf' color forms, and between the tall varieties. The 'Red Malayan Dwarf' is genetically distinct from the 'Green' and 'Yellow Malayan Dwarf', the latter two which cannot be distinguished genetically. Off-type 'Malayan Dwarf' phenotypes (presumed hybrids with talls) can be identified by the markers. Parentage analyses of thirty 'Fiji Dwarf' progeny propagated from five adults surrounded by other cultivars estimates that only 20% of the progeny were out-crossed to the other varieties, while 40-46% were probable selfs. This suggests that a seed production orchard of the variety maintained at reasonable distance from other varieties, will likely yield only 'Fiji Dwarf' genotypes.

Technical Abstract: Using fifteen simple sequence repeat (SSR) microsatellite DNA loci, we analyzed genetic variation within Cocos nucifera germplasm collections at two locations in south Florida, representing eight cultivars. The loci were also used in a parentage analysis of progeny of the 'Fiji Dwarf' variety at both locations. At total of 67 alleles were detected, with eight the highest number in any one locus. The loci uniquely identified 83 of the 110 individual palms. Gene diversity of the 15 loci ranged from 0.778 to 0.223, with a mean of 0.574. 'Fiji Dwarf', 'Malayan Dwarf', 'Green Nino', & 'Red Spicata' cultivars resolve as distinct clusters in a neighbor joining tree using modified Rogers distance, while the tall varieties form two aggregates. The highest gene diversity was found in the tall cultivars ( = 0.583 cumulatively), & the lowest in the 'Malayan Dwarf' (0.202). After the tall coconuts, the 'Fiji Dwarf' was most genetically diverse ( = 0.436), & had the largest number of unique alleles. Genetic identity is highest among the 'Malayan Dwarf' phenotypes, & between the tall varieties. The 'Red Malayan Dwarf' is genetically distinct from the 'Green' & 'Yellow Malayan Dwarf' phenotypes, which cannot be distinguished genetically. Off-type 'Malayan Dwarf' phenotypes (putative hybrids with talls) can be identified genotypically. Parentage analyses of thirty 'Fiji Dwarf' progeny propagated from five adults surrounded by other cultivars estimates that only 20% of the progeny were out-crossed to the other varieties, while 40-46% were possible selfs.