PATTERNS OF DIVERSITY IN FATTY-ACID COMPOSITION IN THE AUSTRALIAN GROUNDNUT GERMPLASM COLLECTION

Knowledge of the amounts and types of fatty acids in groundnut oil is beneficial, particularly from a nutritional standpoint. Germplasm eval uation data for fatty acid composition on 819 accessions of groundnut (Arachis hypogaea L.) from the Australian Tropical Field Crops Genetic Resource Centre, Biloela, Queensland were examined. Data for eight qu antitative fatty acid descriptors have been documented. Statistical as sessment, via methods of pattern analysis, summarised and described th e patterns of variation in fatty acid composition of the groundnut acc essions in the Australian germplasm collection. Presentation of the re sults from principal components analysis and hierarchical cluster anal ysis using a biplot was shown to be a very useful interpretative tool. Such a biplot enables a simultaneous examination of the relationships among all the accessions and the fatty acids. Unlike that information available via database searches, the results from contribution analys is together with the biplot provide a global picture of the diversity available for use in plant breeding programs. The use of standardised data for eight fatty acids, compared to using three specific fatty aci ds, provided a better description of the total diversity available bec ause it remains relevant with possible changes in the nutritional pref erences for fatty acids. Fatty acid composition was found to vary in r elation to the branching pattern of the accessions. This pattern is ge nerally indicative of the botanical types of groundnuts; Virginia (alt ernate) compared to Spanish and Valencia (sequential) botanical types.