^*Author for Correspondence.
Advanced Biotechnology & Breeding Centre
Malaysia Palm Oil Board (MPOB) Headquarters,
6 Persiaran Institusi Bandar Baru Bangi
43000 Kajang,Selangor.
Tel: 03-87694501
Fax: 03-89261995
Email: rajinder@mpob.gov.my

Abstract.
Tissue culture-derived plants of oil palm (Elaeis guineensis) can develop abnormal flowers in which stamen primordia are converted into carpel-like tissues. This often gives rise to abnormal fruits which are said to be ‘mantled’. Individual palms showing variation in mantling and reversion to the normal phenotype over time have been observed. Four ortets and their individual ramets were compared using methylation-sensitive amplification polymorphism (MSAP). Polymorphisms were observed with all methylation-sensitive restriction endonucleases with HpaII giving the highest number of polymorphic bands (0.62%) followed by MspI (0.48%) and PstI (0.19%). Polymorphisms detected were associated with both the mantled characteristic and tissue culture changes. Comparison between HpaII and MspI generated banding patterns showed the occurrence of hypomethylation, hypermethylation, hemi-methylation and change of methylation site, suggesting that the mantling phenotype was not caused by loss of methylation only. In fact, the occurrence of hypermethylation (46.7%) in this study is higher than hypomethylation (32.7%). From the results, it was also clear that the mantled abnormality was not caused by major changes in the genome during tissue culture. The mantled phenomenon was most likely associated with changes in methylation of specific loci. However, no consistent polymorphism was observed between the different sets of normal and abnormal ramets. This suggests that, whilst this method is an effective way of detecting variation in tissue culture-derived plants, it cannot identify the causal basis of the mantled fruit abnormality.