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Vandana V.V.,Indian Institute of Spices Research | Suseela Bhai R.,Indian Institute of Spices Research | Azeez S.,Indian Institute of Horticulture Research
Physiological and Molecular Plant Pathology | Year: 2014

A study on biochemical factors involved in black pepper defense response against Phytophthora capsici, was carried out in P.capsici susceptible (Sreekara) and resistant (04-P24, shows root resistance to the pathogen) black pepper lines. Seven important factors - change in membrane conductance, total phenols, orthodihydroxy (OD) phenols, lignin and defense related enzymes (peroxidase, β-1,3 glucanase and β-1,4 glucanase) - were studied under uninoculated and pathogen (P.capsici, isolate 06-04) inoculated condition to know the preformed and induced responses. The pathogen was inoculated (soil inoculation) and plants were observed for changes, at 24h intervals for 10 days. On 8th day after inoculation symptoms started appearing on Sreekara and increased the severity till 10th day. Both root and stem samples were subjected for biochemical analysis. Of the factors analyzed, it was found that membrane conductance, OD phenol, lignin and peroxidase activity play significant role in root resistance to P.capsici in 04-P24. Light microscopy of the portion of root - where pathogen found attached - was also done. © 2014 Elsevier Ltd.

Patil M.S.,Indian Institute of Horticulture Research
Ecology, Environment and Conservation | Year: 2011

Xanthomonas axonopodis -pv.dieffenbachiae (XAD) is the most important anthurium pathogen. One of the most environment friendly methods to control its spread is to use cultivars that are minimally sensitive to the pathogen. RAPD analysis of genomes from bulk segregant analysis of anthurium hybrids chosen to be the most tolerant and sensitive to XAD were performed to verify DNA polymorphism levels. RAPD analysis was performed using 110 primers with varying template DNA and primer concentrations. Six decamer primers produced 104 polymorphic bands, allowing RAPD profiles typical for one or more of the tolerant hybrids. The extent of polymorphism per primer varied from 61.90 to 88.23 per cent with a mean of 74.80 per cent. A dendrogram based on Squared Euclidian Distance grouped the anthurium in 3 major subgroups. Cloning the more interesting polymorphic DNA fragments in the future will verify the presence of specific genes related to XAD resistance mechanisms in anthurium. © EM international.

Naresh P.,Bangalore University | Reddy M.K.,Indian Institute of Horticulture Research | Ravishankar K.V.,Indian Institute of Horticulture Research
Indian Journal of Genetics and Plant Breeding | Year: 2012

Twenty six accessions of Capsicum annum with varied ripening color were screened for total carotenoids (0.004-0.47%), red carotenoids (0-0.27%) and yellow carotenoids (0.004-0.2%) and also to obtain some new or useful alleles associated with ripening color in chilli, using gene-specific marker. Considerable genetic variability for carotenoids was observed along with the allelic variations of candidate gene Capsanthin capsorubin synthase (Ccs). The results revealed that Ccs gene coding region was present in yellow pepper line LCA 1068 (Aparna) suggesting Ccs gene deletion is not a prerequisite for change in color from red to yellow. Ccs coding region contained no introns but did exhibit polymorphism among chilli lines studied resulting in amino acid changes. Novel allelic variants were found in Byadagi Dabbi (dark red) and LCA1068 (yellow) in the study, which could provide candidate/allele specific molecular markers for selection of lines that may be used in chilli quality breeding for varied colors.

Joshi S.,National Bureau of Agriculturally Important Insects | Kalyanasundaram M.,Tamil Nadu Agricultural University | Asokan R.,Indian Institute of Horticulture Research | Rebijith K.B.,Indian Institute of Horticulture Research
Florida Entomologist | Year: 2013

Mealybugs are major factors limiting the productivity of papaya in India. In June 2012 during a survey for the papaya mealybug, Paracoccus marginatus, and its parasitoid Acerophagus papayae, in Satyamangalam, Tamilnadu, India, a short tailed mealybug was found together with P. marginatus colonizing papaya in 2 plantations. This mealybug was identified as the Jack Beardsley mealybug, P. jackbeardsleyi Gimpel and Miller (Hemiptera: Pseudococcidae), by an integrated taxonomic approach. This work appears to be the first report of P. jackbeardsleyi in India and of papaya as a host of this pest.

Usharani T.R.,Indian Institute of Horticulture Research | Laxmi V.,Indian Institute of Horticulture Research | Jalali S.,Indian Institute of Horticulture Research | Krishnareddy M.,Indian Institute of Horticulture Research
Indian Journal of Biotechnology | Year: 2013

Papaya, a major fruit crop in India and worldwide, is affected by many fungal and viral diseases. A mixed infection of Papaya ring spot virus (PRSV), a linear single-stranded (+) RNA genome of approx 10 kb size, and Papaya leaf curl virus (PaLCV), a bipartite Gemini virus (component A & B) having circular singlestranded DNA (+) genome of about 5.2 kb, has hampered the production and productivity of papaya in many parts of world. Rapid detection techniques are important in prevention of spread of the disease in field conditions. In the present study, a rapid and reliable PCR based detection protocol has been standardized. Sets of primers were designed, based on the respective virus isolate sequence data available in GenBank, to obtain anticipated products of calculated size.

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