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 evaluation 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 quantitative fatty acid descriptors have been documented. Statistical assessment, via methods of pattern analysis, summarised and described the patterns of variation in fatty acid composition of the groundnut accessions in the Australian germplasm collection. Presentation of the results from principal components analysis and hierarchical cluster analysis 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 analysis 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 acids, provided a better description of the total diversity available because it remains relevant with possible changes in the nutritional preferences for fatty acids. Fatty acid composition was found to vary in relation to the branching pattern of the accessions. This pattern is generally indicative of the botanical types of groundnuts; Virginia (alternate) compared to Spanish and Valencia (sequential) botanical types

Factors affecting the global distribution of Hydrilla verticillata

Hydrilla verticillata (Hydrocharitaceae) is a submerged freshwater flowering plant within the monotypic genus. Over the geological periods, fossils of this family and genus have shown distinct diversifications between warm and cool fluctuations with more adaptations occurring in warmer periods and suppressions during severely cold paleoclimate changes. Recently, H. verticillata has shown a wide range of adaptive plasticity, allowing successful proliferation into non-native regions, whilst also undergoing unexplained disappearance from its native localities, and this phenomenon has stimulated this inquiry. Against this somewhat complex background, particular interest for this investigation has been focussed on an understanding of which aspects of climate change have contributed towards global adaptations and distribution patterns of H. verticillata. Whilst it is recognised that some of these changes are natural, other aggravating impacts are due to anthropogenic influences. Identifying the appropriate combinations of these climatic factors (temperature, rainfall, photoperiod), in concert with environmental (water level, CO2, salinity, eutrophication), geographical (altitude, latitude) and other factors (UV-B) are necessary precursors for instituting appropriate management strategies. In this respect, control measures are needed in non-native regions and restoration of this plant in native habitats are essential for its ecologically balanced global distribution. © 2021 European Weed Research Societ