Hybrid Testing and Variety Identification of Coconut (Cocos nucifera L.) in Sri Lanka Using Microsatellite Markers
Currently, there is no reliable method for confirmation of the identity of coconut cultivars and the legitimacy of coconut hybrids. This makes serious problems in coconut breeding and seed production as the identity of coconut cultivars/hybrids can only be approximated at the very late stages of the growth based on reproductive traits owing to long juvenile period and the perennial nature of coconut. A microsatellite (SSR) marker based approach was used to develop an identification method for coconut varieties; Sri Lanka Tall, Sri Lanka Green Dwarf and Sri Lanka Yellow Dwarf, the key parents in the breeding programmes and tall x dwarf hybrids among them, using 18 coconut specific SSR primers. The validity of using yellow colour petiole as a phenotypic marker for the identification of dwarf yellow was also investigated. Two SSR primers, namely CAC20 and CNZ6 have exhibited the potential for distinguishing coconut varieties used as parents in the breeding programme and for confirming hybridity. It was revealed that yellow colour petiole is not a reliable marker for identification of dwarf yellow variety.
Harries, H. C. 1995. Coconut (Cocos nucifera L.). In: Smartt, J., Simmonds, N. W. (Eds.), Evaluation of Crop Plants (2nd Ed.). Longman, London, New York.
Liyanage, D.V., Wickramaratne, M.R.T., Jayasekera, C. 1988. Coconut breeding in Sri Lanka. Cocos 6: 1-26.
Perera, L., Russell, J.R., Provan, J., Powell, W. 1999. Identification and characterisation of microsatellites in coconut (Cocos nucifera L.) and analysis of coconut population in Sri Lanka. Molecular Ecology 8: 344-346.
Perera, L., Russell, J.R., Provan, J., Powell, W. 2003. Studying genetic relationships among coconut varieties/populations using microsatellite markers. Euphytica 132: 121-123.
Rivera, R., Edward, K.J., Barker, J.H.A., Arnold, G.M., Ayad, G., Hodgkin, T., Karp, A., 1999. Isolation and characterization of polymorphic microsatellites in Cocos nucifera L. Genome 42: 1-8
Powell, W., Machray, G.C., Provan, J. 1996. Polymorphism revealed by Simple Sequence Repeats. Trends in Plant Science 1: 215-222
Rongwen, J., Akkaya, M.S., Bhagwat, A.A., Lavi, U., Cregan, P.B. 1995. The use of microsatellite DNA markers for soybean genotype identification. Theoretical and Applied Genetics 90: 43-8
Tancred, S.J., Zeppa, A.G., Grahm, G.C. 1994. The use of PCR-RAPD technique in improving the plant variety rights description of a new Queensland apple cultivar. Australian Journal of Experimental Agriculture 34: 665-667
Torres, A.M., Millan, T., Cubero, J.I. 1993. Identification of rose cultivars using random amplified polymorphic DNA markers. HortScience 28: 333-4
Teulat, B., Trehin, C. R., Lebrun, P., Barker, G.M., Karp, A., Baudouin, L., Rognon, F. 2000. An analysis of genetic diversity in coconut (Cococs nucifera) populations from across the geographic range using sequence–tagged microsatellites (SSRs) and AFLPs. Theoretical and Applied Genetics 100: 764-77