Coconut improvement

The coconut palm, Cocos nucifera, is widely grown throughout the moist tropical regions of the world. Almost every part of the coconut tree is used and it is often referred to as the 'Tree of Life'. Coconuts are predominantly grown by smallholders, with approximately 70 per cent of production being derived from properties of less than 2 ha. The coconut provides the small farmer with most of the essentials of life, including a source of cash. It forms an integral part of the functioning of local communities, particularly small island communities, and supplies a major source of foreign exchange for many countries - Tonga, for example, earns 60% of its export income from coconut products.

The coconut palm is a scientifically neglected crop relative to other agricultural crops of similar importance. It was noted by the Consultative Group for International Agricultural Research Technical Advisory Committee that ... the coconut is the oilseed crop most in need of international research support. International research on the crop is currently underfunded and it has the potential for high pay-off. Furthermore, coconut is a smallholder crop that is ecologically sound and offers a broad range of dietary, income, and employment opportunities.

The Pacific Island countries grow approximately 600,000 ha of coconuts and together form a region that is the fourth largest producer in the world after the Philippines, Indonesia and India. In 1982, coconut production in Papua New Guinea (PNG) and other Pacific islands totalled 2.2 million tonnes, of which approximately 30% (755,000 t in 1982) was produced in PNG. However, the productivity of many coconut palm plantations is declining and the most significant factor is the age structure of plantings. Current statistics from PNG and other Pacific island nations suggest that at least 50 per cent of the existing plantings are considerably older than their commercial life. In order to maintain production for local consumption and to remain competitive on international markets, there is an urgent need for extensive replanting of coconut palms.

PNG provides an excellent example of the multipurpose and changing roles of coconuts. In some areas coconuts are being replaced by large, highly capital intensive oil palm plantations; in others, large areas of cocoa are grown under coconuts; and in coastal and island regions the coconut remains an integral part of village life. PNG accords high priority to research on coconuts and its Government has recently established an institute near Rabaul, New Britain for research on coconut and cocoa.

The establishment of a research program on coconut improvement in PNG is necessarily long-term and involves: (1) breeding of improved genotypes; (2) multiplication of improved genotypes; (3) distribution of improved genotypes; (4) nursery establishment and selection; (5) field establishment of improved genotypes. The aim of the ACIAR Coconut Improvement project is to initiate research on items (2) and (3) and apply the results to nursery management strategies (4). From this will arise a system for the production, rapid multiplication, distribution and establishment of improved coconut germplasm in PNG. This will involve both the initiation of long-term experiments in areas such as suitable planting density and intercropping studies for coconut and cocoa, and specific short-term studies in key research areas essential for the establishment of the coconut improvement program.

The objectives of the collaborative research program in Australia and PNG are to: (1) establish coconut embryo culture technology suitable for use in PNG in a coconut improvement program; (2) establish techniques for the clonal multiplication of coconut embryos; (3) investigate the potential of somatic embryogenesis in coconut improvement programs; (4) establish efficient distribution systems for coconut seednuts, and coconut palm in-vivo and/or in-vitro cultures, to eliminate the problem of germination of nuts during transport - studies will compare alternative systems of distributing improved planting material such as dry-rooted seedlings, polybag seedlings, seedlings excised from the nut, and cultured embryos; (5) develop improved nursery management strategies applicable to smallholders in PNG; (6) obtain quantitative data to evaluate replanting strategies for coconut in PNG; (7) identify which of the above technologies may be applicable to other Pacific island countries for their replanting programs; (8) identify and describe the major coconut types in some of the smaller Pacific island countries.

Expected benefits and application of the in-vitro studies of coconuts include the development of embryo culture techniques in conjunction with disease indexing systems, especially for virus and viroid diseases, which will allow the safe and routine exchange of coconut germplasm between countries. Clonal multiplication of embryos would further facilitate the exchange of germplasm. It could also replace labour intensive hybrid seed gardens as a means of producing coconut hybrids. A limited number of carefully controlled crosses would be made and the resultant hybrid embryos cloned in-vitro. Embryo rescue technology from immature nuts would allow a dramatic increase in yield of hybrid plants from existing seed gardens as 90% of nuts fail to reach maturity. Clonal multiplication of mature palms using tissue culture is a longer term goal but if successful would have as strong an impact on the coconut industry as it is presently having on the oil palm and date palm industries. All in-vitro culture techniques will overcome many of the difficulties of transporting improved plant material.