Prunus necrotic ringspot virus isolates in stone fruit germplasm accessions and cultivars in Israel

Prunus necrotic ringspot virus (PNRSV) was detected in almonds, plum and apricot germplasm accessions and local almond cultivars in Israel. PNRSV was widespread both in wild and cultivated almond trees and uncommon in wild apricots and plums. The possible variation among the PNRSV isolates was initially evaluated by restriction analysis of PCR products representing the CP gene with the endonuclease RsaI and followed by nucleotide sequence analysis of selected isolates. It was concluded that all 13 isolates belong to group PV96, the largest cluster of PNRSV isolates, described previously. Two PNRSV isolates, one from a plum accession and one from an almond cultivar, were found to be distinct members of group PV96 with unique nucleotide modifications not found in other documented isolates of this virus. However, no PNRSV isolate typical to a specific host and/or to the Middle East region could be identified. This study expands the body of data on variability of PNRSV isolates and highlights the importance of assessing the virus status of germplasm collections by applying reliable diagnostic and differentiating methods.     

Arable acronyms analysed – a review of integrated arable farming systems research in Western Europe

Arable production has come under increasing economic and environmental pressures, especially in the last decade. These have derived from over-production, decreased farm incomes and a concern with the possible environmental effects of intensive pesticide use associated with such intensive cultivation. A number of long-term research programmes on integrated farming systems and their sustainability have recently been completed or are currently under way. In the UK, these include the ‘Boxworth’ project, ‘SCARAB’, TALISMAN’, RISC, ‘LINK Integrated Farming Systems’, ‘LIFE’ and the demonstration-only programme ‘LEAF’. These projects are reviewed in terms of their objectives, designs and results to date, and are compared with some parallel programmes in Germany, the Netherlands, Switzerland and France.     

Stratigraphical classification and all that

Quantitative treatment of the geological sciences must remain limited; there continues to be need for a language of words. This is keenly felt in stratigraphy, where the practising geologist is dismayed by the effusions of the stratigraphical philosophers. The situation, in so far as it appears to remain in some ways obscure or troublesome, is briefly reviewed in terms of lithostratigraphy. biostratigraphy. and chronostratigraphy. A revised version of a controversial diagram is presented, in which the role of the boundary stratotype as anchor point is believed to be clarified. Finally a synthesis is attempted of relationships between the various stratigraphical procedures and the provision of dates in years through the parallel discipline of geochronometry.     

The distribution of the freshwater Malacostraca in the area of the Mersey and Weaver River Authority

Freshwater Malacostraca distribution data acquired through the routine biological work of a river authority is of general scientific interest. The distribution of Asellus aquaticus and Gammarus pulex is related to pollution and natural factors. Although widespread in the area, both species are absent from an extensive part of the major river system. A. meridianus appears to be less successful in competition with A. aquaticus and is comparatively scarce, being mostly limited to isolated pools. The distribution of Crangonyx pseudogracilis in canals and static waters is also related to pollution and natural factors. Orchestia cavimana, a semi-terrestrial amphipod, is shown to be an overlooked species which is common in canals.