FRUIT COMPONENT ANALYSIS OF SOUTH-PACIFIC COCONUT PALM POPULATIONS

The south Pacific region contains a large genetic resource for the gen etic improvement of coconut palms (Cocos nucifera L.). A study of the diversity in the species was made during 1992/3 using fruit component analysis on a representative sample from 29 distinct south Pacific pop ulations in order to characterise the germplasm present in the region. A large diversity in fruit morphology was found that ranged from popu lations exhibiting wild-type characters in central Pacific to populati ons displaying domesticated characteristics in Rennell Island, the Sik aiana Islands, the Marquesas Islands, and in Papua New Guinea. Many po pulations exhibited fruit characteristics intermediate between the two , which were thought to have arisen due to introgressive hybridisation between the wild and domesticated populations. Continuous variation i n fruit morphology was found in these populations, and cluster analysi s arbitrarily divided the continuum into discrete groups which were co nsistent with geographic affinities. Groups were defined in Melanesia, Western Polynesia and Eastern Polynesia. The continuum displayed clin al variation from populations with small fruit and low husk content in the west to large fruit and more husk in the east of the region. The wild and domesticated populations were found in disjunct pockets throu ghout the area, and did not form part of the dines. Most populations c onsisted of a wide range of fruit morphology, from individuals express ing wild-type characters to those with domestic-type characters. The o ccurrence of both wild and domesticated populations within the clinal variation indicates that further exploration should be made to determi ne the presence of other potentially useful populations. While this ac tivity is proceeding, collection and conservation can proceed using th e classification already defined.