Restriction fragment length polymorphisms in Fusarium oxysporum f.sp. dianthi and other fusaria from Dianthus species

DNA restriction fragment length polymorphisms (RFLPs) among 46 isolates of Fusarium oxysporum from Dianthus spp., representing the known range of pathogenicity in carnation, were determined using total DNA digested with the restriction enzyme HindIII and a previously described probe, D4. Distinct multiple band RFLP patterns were found, which delineated RFLP groups as follows: (i) F. oxysporum f.sp. dianthi races I and 8; (ii) F. oxysporum f.sp. dianthi races 2, 5 and 6; (iii) F. oxysporum f.sp. dianthi race 4; (iv) a recently described race of F. oxysporum f.sp. dianthi (wilt‐causing isolates from D. caryophyllus formerly classified as F. redolens); (v) wilt‐causing isolates from D. barbatus formerly classified as F. redolens and (vi), (vii) and (viii), three further recently described races of F. oxysporum f.sp. dianthi. Isolate groups derived from analysis of RFLPs were consistent with existing and recently described vegetative compatibility groups (VCGs) in F. oxysporum f.sp. dianthi, but not in all cases with races. Isolates of F. oxysporum and F. proliferatum not associated with wilt disease had simpler RFLP patterns (with one exception) that were not associated with VCGs.</p

Generation of a ribosomal DNA probe by PCR and its use in identification of fungi within the Gaeumannomyces-Phialophora complex

The polymerase chain reaction (PCR) was used to amplify a ribosomal DNA fragment from Gaewnannomyces graminis. This fragment was labelled and tested for its usefulness as a probe in restriction fragment length polymorphism (RFLP) studies of fungi within the Gaeumannomyces-Phialophora complex. When the probe was hybridized to EcoRI digests of DNA from these fungi, there were consistent band pattern differences between the three varieties of G. graminis (tritici, avenae and graminis). This method of probe production, which is more rapid than many others currently used, has considerable potential for use in the identification of these organisms, and may also be applicable to other groups of fungi.Peer reviewe

Avocado Fruit Quality Management during the Postharvest Supply Chain

Avocados are a popular subtropical fruit of high economic importance, and the European Union is the biggest importer of the bulk of the fruit coming from countries such as South Africa, Chile, and Israel. The fruit is highly nutritious, being rich in vitamins A, B, C, minerals, potassium, phosphorus, magnesium, iron, and antioxidants. The biggest challenge is that the fruit is highly susceptible to qualitative and quantitative postharvest losses. Successful maintenance of avocado fruit quality during the supply chain depends on many aspects, including adequate orchard management practices, harvesting practices, packing operations, postharvest treatments, temperature management, transportation and storage conditions, and ripening at destination. Postharvest losses are mostly attributed to flesh softening, decay, physiological disorders, and improper temperature management. Management of the supply chain is solely done to provide the fruit with the most favorable conditions to extend storage life, and retain quality and nutritional attributes of the fruit. The focus of this review is therefore to study the findings that have emanated from research done to retain overall avocado fruit quality and to reduce postharvest losses during the supply chain through the adoption of appropriate and novel postharvest technologies.Post-Harvest Innovation Programme (Fresh Produce Exporter Forum, South Africa, and Department of Science and Technology).http://www.tandfonline.com/loi/lfri202015-06-30hb201