Development of methods for screening sugarcane and Erianthus germplasm for resistance to plant-parasitic nematodes

SINCE PLANT-parasitic nematodes are a major constraint to sugarcane production in Australia and previous research has shown that Erianthus arundinaceus has resistance to both root-knot nematode (Meloidogyne javanica) and root lesion nematode (Pratylenchus zeae), introgressions of sugarcane with this and other wild species are being screened in the glasshouse for resistance to these nematode pests. This paper discusses work that was undertaken to optimise high throughput screening methods of introgression sugar cane clones. In the case of root-knot nematode screening: sandy soils were found to be the best potting medium for growing sugar cane plants, a bleach method of retrieving eggs from roots proved to be the best nematode extraction method and a simple gall rating index produced results that were highly correlated with nematode counts. In the process of undertaking these experiments, previous findings that some Erianthus clones have a high level of resistance to root-knot nematode were confirmed. In the case of root lesion nematode screening; nematode population densities reached a maximum about 11 weeks after pots were inoculated and final nematode population densities were highest in a commercial potting medium. A tray extraction method proved to be the best method of retrieving the root lesion nematodes from roots and soil, but only about 25% of the nematodes were recovered with a 3-day extraction period. On the basis of these results, methods suitable for screening large numbers of sugarcane clones for nematode resistance have been established

Climate-induced changes in the suitable habitat of cold-water corals and commercially important deep-sea fishes in the North Atlantic

We used environmental niche modelling along with the best available species occurrence data and environmental parameters to model habitat suitability for key cold-water coral and commercially important deep-sea fish species under present-day (1951-2000) environmental conditions and to forecast changes under severe, high emissions future (2081-2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean (from 18°N to 76°N and 36°E to 98°W). The VME indicator taxa included Lophelia pertusa , Madrepora oculata, Desmophyllum dianthus, Acanela arbuscula, Acanthogorgia armata, and Paragorgia arborea. The six deep-sea fish species selected were: Coryphaenoides rupestris, Gadus morhua, blackbelly Helicolenus dactylopterus, Hippoglossoides platessoides, Reinhardtius hippoglossoides, and Sebastes mentella. We used an ensemble modelling approach employing three widely-used modelling methods: the Maxent maximum entropy model, Generalized Additive Models, and Random Forest. This dataset contains: 1) Predicted habitat suitability index under present-day (1951-2000) and future (2081-2100; RCP8.5) environmental conditions for twelve deep-sea species in the North Atlantic Ocean, using an ensemble modelling approach.  2) Climate-induced changes in the suitable habitat of twelve deep-sea species in the North Atlantic Ocean, as determined by binary maps built with an ensemble modelling approach and the 10-percentile training presence logistic (10th percentile) threshold. 3) Forecasted present-day suitable habitat loss (value=-1), gain (value=1), and acting as climate refugia (value=2) areas under future (2081-2100; RCP8.5) environmental conditions for twelve deep-sea species in the North Atlantic Ocean. Areas were identified from binary maps built with an ensemble modelling approach and two thresholds: 10-percentile training presence logistic threshold (10th percentile) and maximum sensitivity and specificity (MSS). Refugia areas are those areas predicted as suitable both under present-day and future conditions. All predictions were projected with the Albers equal-area conical projection centred in the middle of the study area. The grid cell resolution is of 3x3 km

Marine Isotope Stage 3 sea level fluctuations: data synthesis and new outlook

To develop a better understanding of the abrupt Dansgaard-Oeschger mode of climate change, it is essential that we establish whether the ice sheets are actively involved, as trigger or amplifier, or whether they merely respond in a passive manner. This requires careful assessment of the fundamental issues of magnitude and phasing of global ice volume fluctuations within marine isotope stage 3 (MIS 3), which to date remain enigmatic. We review recent advances in observational studies pertaining to these key issues and discuss the implications for modeling studies. Our aim is to construct a robust stratigraphic framework for the MIS 3 period regarding sea level variability, using the most up-to-date arguments available by combining insights from both modeling and observational approaches