Skip to main content Accessibility help
×
Home

Excess heterozygosity and scarce genetic differentiation in the populations of Phoenix dactylifera L.: human impact or ecological determinants

  • Sakina Elshibli (a1) and Helena Korpelainen (a1)

Abstract

Extensive research has been conducted on the characterization of hundreds of date palm (Phoenix dactylifera L.) cultivars worldwide. However, the population genetics of date palms has never been studied. In this study, we collected 200 individuals from 19 populations of different geographical locations in Sudan. The collection sites were grouped according to the type of dates (date palm fruits) that dominates in the area. Ten microsatellite markers were used to investigate the genetic diversity within and among populations and the correlation between the genetic and geographical distances. The tested microsatellite markers showed a high level of polymorphism. A total of 261 alleles were detected at the ten loci. The overall mean value of fixation indices equalled − 0.163, which shows the presence of excess heterozygosity. However, the χ2 tests conducted for every locus in each population indicated no significant deviation from the Hardy–Weinberg equilibrium. The analyses of molecular variance exhibited that about 95% of the total genetic variation existed within populations, while significant differentiation within the type groups could be detected. Although significant isolation by distance (r2 = 0.552, P < 0.05) was detected by a Mantel test, it seems that the spatial effect has become complicated as a result from the exchange and introduction of different kinds of plant materials by date palm growers and traders, as well as seed dispersal. This complexity was clearly apparent in the weak clustering relationships among most of the tested populations.

Copyright

Corresponding author

*Corresponding author. E-mail: sakina.elshibli@helsinki.fi

References

Hide All
Adawy, SS, Hussein, EHA, Ismail, SEME and El-Itriby, HA (2006) Genomic diversity in date palm (Phoenix dactylifera L.) as revealed by AFLPs in comparison to RAPDs and ISSRs In: Abstracts 0f 3rd International Date Palm Conference, Abu Dhabi, United Arab Emirates, 19–21 February 2006.
Ahmed, M and Ali, N (1960) Effect of different pollens on the physical and chemical characters and ripening of date fruit. Punjab Fruit Journal 23: 1011.
Al-Khalifah, NS and Askari, E (2003) Molecular phylogeny of date palm (Phoenix dactylifera L.) cultivars from Saudi Arabia by DNA fingerprinting. Theoretical and Applied Genetics 107: 12661270.
Baaziz, M, Majourhat, K and Bendiab, K (2000) Date palm culture in the Maghreb countries: constraints and scientific research. Proceedings of the Date Palm International Symposium, Windhoek, Namibia, 22–25 February, pp. 306311.
Babiker, M and Gudmundsson, A (2004) The effects of dykes faults on groundwater flow in an arid land: The Red Sea Hills, Sudan. Journal of Hydrology 279: 256273.
Billotte, N, Marseilla, CN, Brottier, P, Noyer, JL, Jacquemoud-Collet, JP, Moreau, C, et al. , (2004) Nuclear microsatellite markers for the date palm (Phoenix dactylifera L.): characterisation, utility across the genus Phoenix and in other palm genera. Molecular Ecology Notes 4: 256258.
Cao, BR and Chao, CT (2002) Identification of date cultivars in California using AFLP markers. HortScience 37: 966968.
Chao, CT and Krueger, RR (2007) The date palm (Phoenix dactylifera L.): overview of biology, uses and cultivation. HortScience 42: 10771082.
El-Assar, AM, Krueger, RR, Devanad, PS and Chao, CT (2005) Genetic analysis of Egyptian date (Phoenix dactylifera L.) accessions using AFLP markers. Genetic Resources and Crop Evolution 52: 601607.
Elhoumaizi, MA, Saaidi, M, Oihabi, A and Cilas, C (2002) Phenotypic diversity of date-palm cultivars (Phoenix dactylifera L.) from Morocco. Genetic Resources and Crop Evolution 49: 483490.
Elshibli, S and Korpelainen, H (2008) Microsatellite markers reveal high genetic diversity in date palm (Phoenix dactylifera L.) germplasm from Sudan. Genetica (in press). DOI 10.1007/s10709-007-9232-8.
Excoffier, L, Laval, G and Schneider, S (2005) Arlequin ver. 3.0: An integrated software package for population genetics data analysis. Evolutionary Bioinformatics 1: 4750.
Excoffier, L, Smouse, PE and Quattro, M (1992) Analysis of molecular variance inferred from metric distances among DNA haplotypes: application to human Mitochondrial DNA restriction data. Genetics 131: 479491.
Felsentein, J (1985) Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39: 783791.
Felsentein, J (2005) PHYLIP (Phylogeny Interference Package) version. 3.6. Distributed by the author. Department of Genome Sciences, University Washington, Seattle.
Hamrick, JL, Godt, MJW and Sherman-Broyles, SL (1992) Factors influencing levels of genetic diversity in woody plant species. New Forests 6: 95124.
Hulme, M (1990) The changing rainfall resources of Sudan. Transactions of the Institute of British Geographers 15: 2134.
Jaradat, AA and Zaid, A (2004) Quality traits of date palm fruits in a center of origin and center of diversity. Food, Agriculture and Environment 2: 208217.
Loveless, MD and Hamrick, JL (1984) Ecological determinants of genetic structure in plant populations. Annual Review of Ecology and Systematics 15: 6595.
Li, CC and Horwitz, DG (1953) Some methods of estimating the inbreeding coefficient. American Journal of Human Genetics 5: 107117.
Rousset, F (1997) Genetic differentiation and estimation of gene flow from F-statistics under isolation by distance. Genetics 145: 12191228.
Rice, WR (1989) Analysing tables of statistical tests. Evolution 43: 223225.
Mantel, N (1967) The detection of disease clustering and a generalized regression approach. Cancer Research 27: 209220.
Nei, M (1972) Genetic distance between populations. American Naturalist 106: 283292.
Nixon, RW (1950) Imported cultivars of dates in the United States USDA Circular No. 834: 144.
Nixon, RW (1967) Date culture in Sudan, Date Growers' Institute Report 44: 914.
Nixon, RW and Carpenter, JB (1978) Growing dates in the United States US Department of Agriculture, Agriculture Information Bulletin No. 207: USDA. Technical Document, p. 63.
Osman, AMA (1984) The performance of date palms in the Sudan. Acta Horticulturae 143: 231237.
Osman, AMA (2001) Development of date palm culture in Republic of Sudan Paper presented at a workshop on date palm culture and dates production in Republic of Sudan. Date Palm Research and Development Network, Khartoum, Sudan, 22–17 August..
Sedra, MH, Lashermes, P, Trouslot, P, Combes, M and Hamon, S (1998) Identification and genetic diversity analysis of date palm (Phoenix dactylifera L.) varieties from morocco using RAPD markers. Euphytica 103: 7582.
Soliman, SS, Ali, BA and Ahmed, MMM (2003) Genetic comparisons of Egyptian date palm cultivars (Phoenix dactylifera L.) by RAPD-PCR. African Journal of Biotechnology 2: 8687.
Trifi, M, Rhouma, A and Marrakchi, M (2000) Phylogenetic relationships in Tunisian date-palm (Phoenix dactylifera L.) germplasm collection using DNA amplification fingerprinting. Agronomie 20: 665671.
United Nations Environment Programme(2007) Natural disasters and desertification. In: Sudan – Post – Conflict Environmental Assessment, Nairobi, Kenya. ISBN: 978-92-807-2702-9, pp. 56-69.
Wright, S (1969) Evolution and genetics of populations. The Theory of Gene Frequencies, vol. 2. Chicago: University of Chicago Press.
Wrigley, G (1995) Date palm (Phoenix dactylifera L.). In: Smartt, J and Simmonds, NW (eds) The Evolution of Crop Plants. London: Longman, pp. 399403.
Zaid, A and de Wet, PF (2002a) Botanical and systematic description of the date palm. In: Zaid, A (ed.) Date Palm Cultivation. FAO Plant Production and Protection Paper No. 156. Rome: Food and Agriculture Organisation of the United Nations, pp. 128.
Zaid, A and de Wet, PF (2002b) Origin, geographical distribution and nutritional values of date palm. In: Zaid, A (ed.) Date Palm Cultivation. FAO Plant Production and Protection Paper no. 156, Rome: Food and Agriculture Organisation of the United Nations, pp. 2944.
Zaid, A and de Wet, PF (2002c) Date palm propagation. In: Zaid, A (ed.) Date Palm cultivation. FAO Plant Production and Protection Paper No. 156. Rome: Food and Agriculture Organisation of the United Nations, pp. 7389.
Zaid, A and de Wet, PF (2002d) Pollination and bunch management. In: Zaid, A (ed.) Date Palm Cultivation. FAO Plant Production and Protection Paper No. 156. Rome: Food and Agriculture Organisation of the United Nations, pp. 145175.
Zaid, A, de Wet, PF, Djebri, M and Oihabi, A (2002) Diseases and pests of date palm. In: Zaid, A (ed.) Date Palm Cultivation. FAO Plant Production and Protection Paper No. 156. Rome: Food and Agriculture Organisation of the United Nations, pp. 227242.
Zehdi, S, Trifi, M, Billotte, N, Marrakchi, M and Pintaud, JC (2004a) Genetic diversity of Tunisian date palms (Phoenix dactylifera L.) revealed by nuclear microsatellite polymorphism. Hereditas 141: 278287.
Zehdi, S, Sakka, H, Rhouma, A, Ould Mohamed Salem, A, Marrakchi, M and Trifi, M (2004b) Analysis of Tunisian date palm germplasm using simple sequence repeat primers. African Journal of Biotechnology 3: 215219.
Zhang, X, Korpelainen, H and Li, C (2006) Microsatellite variation of Quercus aquifolioides populations at varying altitudes in the Wolong natural reserve of China. Silva Fennica 40: 407415.

Keywords

Excess heterozygosity and scarce genetic differentiation in the populations of Phoenix dactylifera L.: human impact or ecological determinants

  • Sakina Elshibli (a1) and Helena Korpelainen (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed