Commercial-scale propagation and planting of elite oil palm clones: research and development towards realization

The announcements of breakthroughs in plant regeneration from tissue cultures of oil palm in the 1970s ushered in a new chapter in oil palm genetic improvement with projected yield increase of clones exceeding 30% over hybrid seeds. However, the subsequent ubiquitous appearance of the mantled fruit somaclonal variant in regenerated palms resulted in the early commercial oil palm tissue culture laboratories reverting to further research and development (R&D). Applied Agricultural Resources Sdn Bhd persisted and, through its R&D, circumvented the impeding issues of unacceptably high fruit mantling, and low efficiencies of tissue culture amenability and selection of elite palms. In the process, it has established viable large-scale commercial propagation of oil palm clones by gel and liquid culture methods by the late 1990s. This achievement has since been emulated by more than a dozen commercial laboratories in Malaysia and elsewhere, producing about 3.5 million ramets per year. This apparent success has led industry to believe that oil palm cloning is an established and efficient technology, and that more tissue culture laboratories to produce more high-yielding clones to replace hybrid seeds in planting and replanting will resolve the stagnating national yields. Much of the increased ramet production comes from more laboratories culturing more palms than in improved cloning efficiencies. Most of the clones currently produced are also derived either from advanced dura (D) x pisifera (P) hybrids or from commercial DxP fields with low heritability for yield. Consequently, the expected yields of the clones would not be much different from those of near true F1 and clonal hybrids which are currently available at a much reduced cost and without the attendant mantling risk. The agro-management needs of clonal plantings to maximize their fruit bunch yield potential have yet to be systematically addressed through scientific experimentation. Cloning ortets from the early or recombinant phases of hybrid breeding programmes would be more efficient with the wider genetic variability and higher heritability for yield and other desirable traits. Perhaps the biggest advantage of cloning would be in the early commercial exploitation of new genetic materials from introgression programmes of wide intra- or inter-specific crosses which would also broaden the genetic base of the commercial plantings to reduce the risk of genetic vulnerability to pests, diseases and environmental stress. Clones are unlikely to supersede hybrid seeds as the dominant oil palm planting material until the amenability and fidelity deficiencies in tissue culture have been further resolved or circumvented, and their field performance advantage over concurrent improved hybrids clearly demonstrated