Central Tuber Crops Research Institute

About: Central Tuber Crops Research Institute is a facility organization based out in Thiruvananthapuram, Kerala, India. It is known for research contribution in the topics: Starch & Fermentation. The organization has 475 authors who have published 587 publications receiving 10285 citations.

Physicochemical properties of the starchy flour extracted from sweet potato tubers through lactic acid fermentation

Abstract: The efficiency of starch extraction from sweet potato tubers was improved by lactic acid fermentation using a mixed culture inoculum. Study of the properties of the starchy flour showed that there was a significant reduction in the starch content and consequently the soluble and apparent amylose contents of fermented samples from all six varieties used. A fall in peak viscosity and viscosity breakdown was observed for fermented samples, while the pasting temperature was enhanced significantly. The fermented flour showed greater solubility and reduced swelling. Differential scanning calorimetry studies indicated a delay in gelatinisation and a fall in enthalpy of gelatinisation of the starch on fermentation. Unlike cassava, all the properties of the starch from sweet potato tubers, ie viscosity, swelling, solubility, gelatinisation temperature, amylose content and starch content, were affected by fermentation, and variation was also observed among cultivars. Copyright © 2005 Society of Chemical Industry

Detection and Classification of Mosaic Virus Disease in Cassava Plants by Proximal Sensing of Photochemical Reflectance Index

Abstract: Cassava Mosaic virus Disease (CMD) is the most severe and widespread virus infection that affects cassava (Manihot esculenta Crantz) crops. This paper investigates the application of photochemical reflectance index (PRI) imaging to detect and assess the impact of varying levels of CMD infection in cassava. Towards this, narrow band reflectance images of field-grown cassava plants were recorded at 531 and 571 nm by proximal sensing with a multispectral imaging system (MSIS). It was observed that the PRI values increase with increasing levels of CMD infection in all the varieties of cassava studied. A scatter plot of the PRI image intensity yielded a sensitivity of 85 % and specificity of 79 % for discriminating visibly no CMD from initial CMD and a sensitivity of 93 % and specificity of 92 % for discriminating initial CMD from advanced CMD. Area under the receiver operator characteristics (AUC-ROC) curve was used to discriminate the CMD infection level by differentiating visibly no CMD from initial CMD [AUC = 0.92] and initial CMD from advanced CMD [AUC = 0.99]. It was observed that PRI values determined from the experimental data follow a linear inverse relationship with net photosynthetic rate (Pn) (R 2 = 0.76) and total leaf chlorophyll (Chl) content (R 2 = 0.80). The results show that PRI imaging can be utilized to discriminate healthy plants from CMD and other stress infected crops by proximal sensing in outdoor plants.

Inheritance pattern of tetraploid Dioscorea alata and evidence of double reduction using microsatellite marker segregation analysis

Abstract: Recent studies have shown that the basic chromosome number of the three major edible yams, Dioscorea alata, Dioscorea rotundata and Dioscorea trifida, is x = 20, and that the clones with 2n = 40 chromosomes are diploids. D. alata breeding programmes were limited to the production of diploid hybrids until 2006, when the tetraploids (2n = 80) were found to be fertile and polyploid hybrids were produced by conventional hybridisation. However, the nature of the polyploidy (autotetraploidy or allotetraploidy) was not known in D. alata tetraploid clones. In the present study, the inheritance pattern of simple sequence repeat markers was determined in a tetraploid progeny using a Bayesian approach and by examining double reduction events. Results obtained confirm the autotetraploid nature of the 2n = 80 clones of D. alata.

Optimization of media and temperature for enhanced antimicrobial production by bacteria associated with Rhabditis sp.

Abstract: Background and Objectives: Entomopathogenic nematodes, belonging to the family heterorhabditis and steinernematidae, are reported to be symbiotically associated with specific bacteria and the secondary metabolites produced by these bacteria possess antimicrobial activity. In this study, bacteria were isolated from nematodes belonging to the family rhabditidae, and the antimicrobial activity was tested against four bacteria viz. Bacillus subtilis MTCC 2756, Staphylococcus aureus MTCC 902, Escherichia coli MTCC 2622, and Pseudomonas aeruginosa MTCC 2642 and five fungi viz. Aspergillus flavus MTCC 183, Candida albicans MTCC 277, Fusarium oxysporum MTCC 284, Rhizoctonia solani MTCC 4634 and Penicillium expansum MTCC 2006. Materials and Methods: The isolated bacteria were cultured in nutrient broth (NB), Luria broth (LB) and Tryptic soya broth (TSB) at 25, 30 and 35oC. Cell free culture filtrate was prepared by centrifugation and was separated into organic and aqueous fractions. Organic fraction was concentrated and tested for antimicrobial activity. Results: The culture filtrate of the bacteria isolated from the entomopathogenic Rhabditis sp. was found to possess antimicrobial activity against the four bacteria and five fungi tested. The bacterium grew well in TSB, LB and NB media though in TSB yield and activity were higher. Antimicrobial activity was higher at 30oC as compared with 25 or 35oC. HPLC analysis indicated major differences in peak areas and retention times at different temperatures. Increased number of peaks with higher peak areas was obtained at 30oC. Conclusion: The study suggests that the bacteria could produce more bioactive molecules effective against medically and agriculturally important bacteria and fungi depending on culture media and temperature. Modified media could yield different types of molecules effective against diseases/disorders of plant, animals and humans.

Biochemical Changes in Leaf Tissues of Taro [Colocasia esculenta L. (Schott)] Infected with Phytophthora colocasiae

Abstract: The changes in some biochemical parameters due to Phytophthora leaf blight infection were assessed in leaf tissues of one resistant (DP-25), two moderately resistant (Duradim and Jhankri) and one susceptible (N-118) genotypes of taro [Colocasia esculenta (L.) Schott]. Phytophthora spore suspension (15 000 spore ⁄ ml water) was sprayed onto the in vitro raised taro plantlets at 30 days after establishment in pots to induce disease. In comparison with the uninoculated leaves, blight infected leaves showed reduction in protein content and activity of nitrate reductase and increase in total soluble sugar, reducing sugar content and activities of acid phosphatase and alkaline phosphatase among the studied genotypes. Changes in biochemical parameters under induced blight stress as compared with uninoculated control were less in resistant genotypes than that in susceptible genotype. The deviations in biochemical contents were highest in susceptible genotype N-118. Based on the variations of above parameters under stress and non-stress control among the four tested genotypes, the overall pattern of changes was N-118 > Duradim > Jhankri > DP-25, which is in accordance with the pattern of increasing resistance. The resistant genotypes could be used for commercial cultivation and genetic improvement programme to develop resistant varieties to Phytophthora leaf blight disease.