Molecular Characterization of Phytophthora nicotianae Associated with Diseases of Horticultural Crops by RFLP of PCR Internal Transcribed Spacer Region of Ribosomal DNA and AFLP Fingerprints

Molecular characterization of Phytophthora isolates from tobacco, tomato, carnation, gerbera, crossandra and periwinkle was carried out using internal transcribed spacer(ITS) regions of rDNA gene repeat and amplified fragment length polymorphism (AFLP). All the isolates of Phytophthora were identical in morphology and ITSRFLP patterns, indicating P. nicotianae and P. parasitica are synonymous. However, based on AFLP, four sub groups were evident within population of P. nicotianae (P. parasitica): Group I, includes isolates from tomato, tobacco and periwinkle. Isolates from carnation represents Group II. Isolates from gerbera falls under group III. The crossandra isolates formed a Group IV. Thus, present study showed the existence of four molecular sub groups within population of P. nicotianae (P. parasitica) in India

Arecanut and human health

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Detection and Quantification of Alternaria solani in Tomato by Real Time PCR

A conventional and real-time PCR assays using SYBR Green for the detection and quantification of A. solanihave been developed and validated. A primer set (ALP and ITS4) designed from the ITS region of A. linicola/ A. solani complex, yielded a 536 bp product when DNA from 38 isolates of A. solani were amplified. No product was amplified from A. alternata, A. brassicae, A. brassicicola, A.helianthi, A. porri, A. sesami, A.carthami, A.ricini, Colletotrichum gloeosporioides, C. capsici, C. falcatum, Cercospora canescens, C. capsici, Phytophthora infestans, Sclerotium rolfsii, Fusarium equiseti, F. oxysporum, Rhizoctonia solani, Phoma exigua, Curvularia spp and Drechslera. In addition, ALP/ITS4 primers were successfully utilized in real-time PCR assays of A. solani. The efficiency of conventional and real-time PCR assays was compared. The conventional PCR was able to detect the pathogen on symptomatic artificially infected tomato plants 5 days after pathogen inoculation. The detection limit was 100 conidia and 10 pg of DNA in the case of conventional PCR. Real-time PCR exhibited a detection limit 10 times lower (10 conidia, 10fg of DNA). The application of real time PCR assay for rapid detection of A.solani in infected tomato plant material is discussed

Large sub-clonal variation in <i>Phytophthora infestans</i> from recent severe late blight epidemics in India

Abstract The population structure of the Phytophthora infestans populations that caused the recent 2013–14 late blight epidemic in eastern India (EI) and northeastern India (NEI) was examined. The data provide new baseline information for populations of P. infestans in India. A migrant European 13_A2 genotype was responsible for the 2013–14 epidemic, replacing the existing populations. Mutations have generated substantial sub-clonal variation with 24 multi-locus genotypes (MLGs) found, of which 19 were unique variants not yet reported elsewhere globally. Samples from West Bengal were the most diverse and grouped alongside MLGs found in Europe, the UK and from neighbouring Bangladesh but were not linked directly to most samples from south India. The pathogen population was broadly more aggressive on potato than on tomato and resistant to the fungicide metalaxyl. Pathogen population diversity was higher in regions around the international borders with Bangladesh and Nepal. Overall, the multiple shared MLGs suggested genetic contributions from UK and Europe in addition to a sub-structure based on the geographical location within India. Our data indicate the need for improved phytosanitary procedures and continuous surveillance to prevent the further introduction of aggressive lineages of P. infestans into the country

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A journey with the farmers

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Not AvailableLarge-scale production of hybrid seed nuts of commercially cultivated palms such as coconut, arecanut, oil palm and date palm is of prime importance due to the high demand for hybrid nuts and their role in augmenting the production of these crops. However, commercial production of hybrid nuts in these crops is impeded by various factors such as height of the palms, cost and availability of labour, low percentage of fruit-setting, seasonal influences like monsoon rains, etc. We report here the development and use of a simple, viable, cost-effective and labour-saving device for pollinating tall palms from ground-level, which is ideal for large-scale commercial production of coconut hybrids, even by farmers. At least four climbs per coconut palm can be saved by this method during the hybridization process. This simple method can enhance the availability of hybrid seedlings at a cheaper rate to coconut farmers. This method of pollination developed for coconut, can easily be adapted to other commercially important palms depending on the bunch morphology.Not Availabl