Search

Processing and value addition have gained tremendous focus in recent years and therefore breeding for improved quality traits and development of varieties suitable for various processing methods and products assumes significance. This study aimed at determining the genetic variation and identifying parents for developing hybrid clones suitable for processing in sweet potato based on five important processing traits namely starch content, sugar content, dry matter content, flour yield and peel loss. Significant variability for all the selected processing traits was found among the 18 genotypes studied which encompasses the scope of mining the germplasm further for processing and consumer traits. Nine genotypes recorded dry matter content of above 30%. Dry matter content had highly significant and positive correlation with starch and flour yield and significant positive correlation with sugar content. Flour yield exhibited the highest heritability followed by dry matter content, peel loss, sugar and starch contents. The Principal Component Analysis (PCA) analysis identified two principal components explaining 39.11% and 26.40% of total variation observed. Two major and six sub clusters were formed using unweighted pair group method with arithmetic mean (UPGMA) clustering approach. High and low starch varieties were grouped separately in two different clusters. The sensory evaluation of fried chips demonstrated that genotypes such as S1652, S1712, S27 and S1609 were found suitable for processing into fried chips. The score for willingness to buy was found to be high for fried chips of S1652, Kanhangad, S1609, Varsha and S27. Genotypes such as S1652, Bhu Sona, Bhu Krishna, Kamala Sundari and S1712 were found to be highly suitable for consumption after boiling. The genotypes identified in this study can be utilised for the development of varieties suitable for varied end uses. The findings of this study strongly suggest that varieties suitable for processing can be identified among the germplasm based on evaluation of processing traits.

There is a preference for organic vegetables, including Chinese potato [Plectranthus rotundifolius (Poir.) Spreng. or Solenostemon rotundifolius (Poir.) J.K. Morton], due to concerns regarding plan...

It is essential to elucidate genetic diversity and relationships among related varieties of origin and landraces for improving the breeding process. Since rice breeding has improved agronomic traits such as yield and eating quality during green revolution, modern rice varieties are originated from narrow genetic resource and closely related. To resolve the population structure and genetic diversity in bold type rice varieties of southern India, we used a total of 81 rice genotypes by 100 simple sequence repeat markers composed of 36 improved varieties and 45 landraces, which are representative and important for bold type grain rice breeding. The landraces exhibit greater gene diversity than improved lines, suggesting that landraces can provide additional genetic diversity for future breeding. Clustering by Ward method was done to establish a relationship among the 81 rice genotypes. All the genotypes were clustered into mainly 5 clusters. Principle component analysis revealed that the first principal component revealed 42.87% variation, while the second component showed 14.01% variation. Among the eight morpho-physiological and plant production traits studied, the relative water content and spikelet fertility percentage contributed towards maximum diversity. Principle co-ordinate analysis evidently differentiated the genotypes to high yielding varieties with common ancestry. Population structure analysis also obviously classified the genotypes into high yielding susceptible and indigenous tolerant groups. These old varieties and landraces present in crop germplasm collections represent a strategic reserve of genetic variation that can be tapped for varieties and understanding of stress response and developing new varieties that are physiologically adapted to highly variable, climate-resilient environments.

Among the tropical tuber crops, cassava (Manihot esculenta Crantz) deserves special attention as regards to its higher biological efficiency in terms of dry matter production which incidentally implies to the higher amount of nutrient extraction from the soil resulting in better response to the application of manures and fertilizers. Among the major nutrients, Potassium (K) is considered as the key nutrient for cassava owing to its influence both in tuber yield and tuber quality. The above facts as well as the availability of sufficient cassava genotypes in the germplasm collection of ICAR-CTCRI made us to initiate research work to screen cassava germplasm including the pre breeding lines. The objective being to identify K efficient genotypes which can yield well under limited availability of K so that the external application of K can be reduced. This paper describes the wide variation noticed during the pre evaluation of 83 elite genotypes which was done as a prelude in the screening and identification of K efficient genotypes. The characters studied were tuber yield, tuber characters, plant dry matter percentage, plant K content, tuber quality (starch, cyanogenic glucosides) attributes, physiological efficiency and plant biometric characters. The variation among the genotypes for the above traits was assessed by making some yardstick for classification which in turn helped in determining the percent distribution of genotypes in each category. The variation among the genotypes were further affirmed through principal component analysis, wherein the first five components explained more than 77% of variability and the cluster analysis performed grouped these genotypes into five clusters. The biplot showed the traits which are closely linked to the genotypes. The dendrogram constructed indicated similar genotypes to that of the clusters to the extent of more than 50% revealing the association of members with similar traits in clusters and dendrograms. The study helped in establishing the drastic variation among the genotypes along with identification of six genotypes viz., Aniyoor, 7 Sahya (2), 7 III E3-5, W-19, CR 43-8, 6-6 for further detailed experimentation to identify K efficient genotypes.

Nitrogen (N) is the “prime” among the three major nutrients required for plant growth. The large potential demand of nitrogen for plant growth is mainly achieved through biological nitrogen fixatio...

Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson), is an important edible tropical tuber crop, belonging to the family Araceae. Corms produced by this plant is very big and they are rich in starch, protein, mineral, vitamins, and dietary fiber but has acridity problem. This crop is susceptible to virus and phytoplasma diseases which affects crop growth and corm yield. Even though this crop has high commercial value, the problems like susceptibility to viral diseases, acridity problems, and lack of genetic diversity made hindrance in their exploitation. These issues can be resolved only by improving the characters through genetic transformation. To achieve genetic transformation in this important crop, a study was conducted to optimize various parameters for efficient Agrobacterium-mediated genetic transformation using embryogenic calli with vectors having gus reporter gene. Calli were developed using petiole and leaves of in vitro plantlets of elephant foot yam cultivar Gajendra and experiments were conducted to evaluate the sensitivity of calli to different doses of antibiotics viz. geneticin, hygromycin, ticarcillin. It was observed that complete death and discoloration of the calli were obtained with 25 mgl(−1) geneticin and 10 mgl(−1) hygromycin. The lowest lethal concentration of ticarcillin against Agrobacterium growth was found to be 500 mgl(−1) which did not affect calli growth. Optimized parameters for efficient transformation in elephant foot yam include 100 μM acetosyringone concentration with 2 days of co-cultivation at temperature 22 °C using LBA4404 strain. The putative transformants were characterized for the integration of the gus gene using PCR and nucleic acid spot hybridization. The optimized protocol is simple and reproducible and may be adapted for other cultivars also. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02824-6.

Phosphorus (P) is the second key nutrient for plants and it affects several attributes of plant growth. Identification of a potent phosphate solubilizing microorganism capable of transforming the i...

Sustainable alternative agricultural practices like organic farming have evinced interests due to public consciousness about food safety, environmental pollution, soil quality and human health. The study aimed to evaluate the productivity, soil quality, energetic and economic aspects under organic vs conventional management in cassava (Manihot esculenta Crantz). Field experiments were conducted over a three year period at ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, India in split plot design with three varieties of cassava, H-165, Sree Vijaya and Vellayani Hraswa, in main plots and five production systems, traditional, conventional, integrated and two types of organic (without and with microbial inoculants) in sub plots. Organic management (without microbial inoculants) (27.26 t ha−1) produced insignificant yield increase (+2.40%) over conventional system (26.62 t ha−1). The industrial (H-165) as well as domestic varieties (Sree Vijaya, Vellayani Hraswa) of cassava exhibited similar performance under the different production systems. At the end of the third crop, soil chemical properties like pH and organic C were significantly enhanced by 1.15 unit and 22.58% under organic (with microbial inoculants) over conventional system, whereas the soil porosity, cation exchange capacity and exchangeable Ca were significantly higher by 9.36, 27.32 and 29.10% in the organic (without microbial inoculants) over conventional. Besides, biological improvement of the soil with higher counts of bacteria, fungi and actinomycetes and greater activity of soil enzymes like acid phosphatase and dehydrogenase were also observed under organic (with microbial inoculants) system. Both the organic practices (without and with microbial inoculants) scored higher soil quality index (SQI) over the rest, but similarly (0.98 and 0.94 respectively). The soil pH, exchangeable Ca, dehydrogenase enzyme activity and porosity were the decisive factors that governed SQI in the present study. Organic system (without microbial inoculants) proved to be the most energy efficient as evidenced from the highest energy output (152.63 × 103MJ ha−1), net energy (143.55 × 103MJ ha−1), energy use efficiency (16.80) and energy productivity (3.00 kg MJ−1). Organic system generated the highest net income (US $ 4977.57 ha−1) statistically similar to conventional (US $ 4833.10 ha−1) and organic with microbial inoculants (US $ 4720.69 ha−1). Hence organic practices can be recommended for sustainable cassava production.

Potato, cassava, sweet potato, banana and lentil starches were modified with citric acid (CA) with the main objective of enhancing the resistant starch (RS) and slowly digestible starch (SDS) fractions and to compare starches of diverse botanical origins. The percentage CA substitution of modified starches ranged from 3.84 to 15.06 and showed similar type of XRD patterns, but with variation in intensity and percentage crystallinity. The peaks around 1705 cm−1 and 1150 cm−1 in FT-IR spectra of modified starches confirmed the presence of CA group. Scanning electron microscopy confirmed that there were no noticeable changes in granular structure and morphology. No peaks could be observed in RVA pasting profiles of modified starches, confirming cross-linking reaction. The SDS and RS were significantly higher in modified starches of all origins and consequently there was a lower estimated glyceamic index (EGI). Modified starches were associated with lower setback viscosity indicating their lower temperature stability.

Resistant starch (RS), RS4 type, has been synthesized by octenyl succinylation of sweet potato, lentil and banana starches and comparatively evaluated for their physicochemical and digestibility properties. The effect of substitution level and physicochemical properties of the modified starches were correlated with their in vitro starch digestibility, rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) contents. The modified starches were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) analyses. The three starches showed distinctly different digestibility and functional properties along with different crystalline pattern, granule shape and sizes. The octenyl succinylated starches showed a significant increase in RS and SDS when compared to the corresponding native starches. Correlation analysis showed that degree of substitution, swelling power and gelatinization temperatures of the modified starches were positively correlated to RS whereas negative correlation was observed for syneresis, setback viscosity and loss modulus with RS.

The structure and in vitro antiproliferative activity of anthocyanins in the root tubers of a sweet potato variety cv. Bhu Krishna and the purple leaves of a promising accession S-1467 were studied with the objectives of understanding the structure-activity relationship and comparing the leaf and tuber anthocyanins. The chemical structure of anthocyanins was determined by high-resolution electrospray ionization mass spectrometry analysis. A fluorescence-resonance-energy-transfer-based caspase sensor probe had been used to study the antiproliferative property, and analysis of the cell cycle was performed after staining with propidium iodide and subsequent fluorescence-activated cell sorting. Structurally, the anthocyanins in root tubers were identical to those in leaves, but there was a difference in the proportion of various aglycones present in both. This has led to distinguishable differences in the antiproliferative activity of leaf and tuber anthocyanins to various cancer cells. All nine anthocyanins were found in acylated forms in both tubers and leaves. However, peonidin derivatives were major anthocyanins in tubers (33.98 ± 1.41 mg) as well as leaves (27.68 ± 1.07 mg). The cyanidin derivatives were comparatively higher in leaves (20.55 ± 0.91 mg) than tubers (9.44 ± 0.94 mg). The tuber and leaf anthocyanins exhibited potential antiproliferative properties to MCF-7, HCT-116, and HeLa cancer cells, and the structure of anthocyanins had a critical role in it. The leaf anthocyanins exhibited significantly higher activity against colon and cervical cancer cells, whereas tuber anthocyanins had a slightly greater effect against breast cancer cells.

Dasheen mosaic virus (DsMV) the main causative agent of mosaic disease in elephant foot yam (Amorphophallus paeoniifolius) belongs to Potyviridae. The complete genome sequence of DsMV infecting A. paeoniifolius in Kerala state, India was assembled from the whole transcriptome sequencing reads of diseased host samples. The sequence of the virus which showed 83% identity with DsMV infecting Zantedeschia aethiopica (China) was confirmed through amplification and sequencing with primers designed based on the assembled sequence. Unambiguous recombination events mainly confined to the 5′ terminal 4000 nucleotides of the genome with phylogenetically related potyviruses were recognized. The length and genome composition towards the 3′ end comprising NIb, CP and 3′ UTR were not dependent on the host or the source region.

A novel co-culture method using the beneficial root endophytic fungus Piriformospora indica and a plant-growth promoting rhizobacterial strain of Bacillus pumilus to promote the growth of tomato seedlings in plug trays, is described. Coconut water, a waste product from the coconut industry, was used as medium for co-cultivation of the two biological agents. During the co-culture with the fungus, the bacterial strain showed a similar growth rate to that in monoculture in fresh autoclaved coconut water. In contrast, co-culture in potato dextrose broth (PDB), a medium routinely used for cultivation of the endophytic fungus, did not support bacterial growth. Inoculation with the co-culture or a mixture of P. indica and B. pumilus promoted tomato seedling growth significantly when compared with individual application of the two biological agents. No difference was observed with respect to the degree of root colonization in tomato seedlings whether it was done with a monoculture or a co-culture with rhizobacterium. The co-culture system developed reduces the cost of inoculum production as it uses coconut water, a cheap and locally available waste product and a single fermentation vessel. Further research is required to know the endophytic nature of the rhizobacterial strain and its possible role in helping the fungus in root colonization.

The present study tried to explore the possible in vitro biocontrol mechanisms of Lysinibacillus sphaericus, a diazotrophic endophyte from rice against the rice sheath blight pathogen Rhizoctonia solani. The in vivo biocontrol potential of the isolate and the induction of systemic resistance under greenhouse conditions have also been experimented employing different treatments with positive control carbendazim, the chemical fungicide. The endophytic isolate showed 100% growth inhibition of the fungal pathogen via volatile organic compound production and was positive for the production of siderophores, biosurfactants, HCN, and ammonia. Under greenhouse conditions, foliar and soil application of L. sphaericus significantly decreased the percentage of disease incidence. All bacterized treatments are superior to chemical fungicide treatment. Application of L. sphaericus in single and combination treatments induces systemic resistance as evident from the significant accumulation of defense enzymes such as peroxides, polyphenol oxides and phenylalanine ammonia in addition to the increase of phenolic compounds. The results biologically prospect endophytic diazotroph L. sphaericus as a potent plant growth promoter with excellent biocontrol efficiency.

The experiment was conducted at Krishi Vigyan Kendra, Bilaspur during 2017-18 and 2018-19 to find out alternatives to manual weeding in elephant foot yam. The manual weeding and herbicides alone and in combinations were tried. The results revealed that pre emergence application of alachlor @1.00 kg a.i./ha along with hand weeding after 60 days of planting is the most effective and economic treatment for weed management and getting highest return in elephant foot yam variety 'Palam Zimikand-1' under low hill condition of Himachal Pradesh.

Gene regulatory networks play an important role the molecular mechanism underlying biological processes. Modeling of these networks is an important challenge to be addressed in the post genomic era. Several methods have been proposed for estimating gene networks from gene expression data. Computational methods for development of network models and analysis of their functionality have proved to be valuable tools in bioinformatics applications. In this paper we tried to review the different methods for reconstructing gene regulatory networks.

Graft copolymerization of poly(acrylonitrile) onto cassava starch was carried out with potassium persulphate (PPS) as the free radical initiator using a response surface Box–Behnken design. Different levels of monomer concentration, initiator concentration, and temperature were used, and regression models were generated in terms of these factors, which can be used to predict the grafting level and efficiency at a given level of the factors. The grafted starches were characterized by FTIR, XRD, and SEM analyses and determination of %grafting (%G), N-content, thermal properties, water and saline solution retention, and rheological properties. Under the conditions used, %G was found to depend only on the temperature used for the reaction. The maximum %G of 120.1 was obtained for the sample synthesized under the following conditions: weight of AN = 0.753 mol/10 g starch, weight of PPS = 0.284 g and temperature = 55°C, and the grafting efficiency was 30.03%. The absorption bands at 2243 cm−1 for the nitrile group (CN) in the FTIR spectra of the products confirmed the grafting reaction. There was a decrease in crystallinity and disappearance of the granular structure after grafting of the starch. The melting temperatures of the graft copolymers determined by differential scanning calorimetry analysis were higher than that of the native starch. The grafted starches exhibited very high thermal stability as observed from the thermogravimetric analysis. The superabsorbent polymer prepared from the grafted starch by alkali saponification exhibited a maximum water absorbency of 636 g/g. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

BACKGROUND: Short-duration (6–7 months) cassava provides opportunities to smallholder farmers for effective utilisation of resources such as land, moisture and nutrients as well as diversification of enterprise and income. The variation in biomass production and partitioning, seasonal course of growth indices, yield, quality and nutrient uptake of ten short-duration/early-bulking genotypes of cassava and their impact on nutrient contents in soil in a lowland situation akin to rice fallow were examined in this study. RESULTS: Triploid 2–18 gave the highest yield (38.34 t ha−1), followed by triploid 4-2, Sree Vijaya, Sree Jaya and Vellayani Hraswa, which were on a par (30–32 t ha−1). Vellayani Hraswa, Sree Vijaya and triploid 4-2 had significantly higher tuberous root dry matter content (370–380 mg g−1) and fairly higher starch content (270–280 mg g−1). All genotypes except triploid 4-2, triploid 2–18 and H-165 had low cyanogen content (29.2–43.8 µg g−1), well within the tolerable limit. Tuberous root dry matter and total dry matter production, crop growth rate, tuberous root bulking rate and harvest index at the last phase, number of tuberous roots, mean weight of tuberous roots and nutrient uptake showed significant positive correlations with tuberous root yield. Principal component analysis also showed a similar trend. CONCLUSION: The diploids Sree Vijaya, Sree Jaya, Vellayani Hraswa and Kalpaka are ideal for cultivation in rice fallow for food use owing to their high yield, good cooking quality and low cyanogen content. The triploids are better suited for industrial use owing to their high tuberous root dry biomass production. Copyright © 2009 Society of Chemical Industry

The normal-Laplace distribution introduced by Reed and Jorgensen [Reed, W.J., Jorgensen, M., 2004. The double Pareto-lognormal distribution, A new parametric model for size distributions. Comm. Statist-Theory and Methods, 33, 1733–1753], is studied briefly. A first order autoregressive process with normal-Laplace stationary marginal distribution is introduced and various properties are discussed. The process gives a combination of Gaussian as well as non-Gaussian time series models for the first time and is free from the zero defect problem. Simulation studies are done and sample path properties are explored. Regression behaviour of the process is studied. The applications in modelling data from various contexts are also discussed.

Chlorpyrifos is a commonly used organophosphate pesticide. Its extensive use and associated serious soil and water contamination have gained increasing environmental concern. Biodegradation is a promising way to remediate chlorpyrifos contamination. There are many reports on various chlorpyrifos degrading microorganisms, but only a few on biodegradation of chlorpyrifos by consortia. Hence, the present study attempted to assemble a novel bacterial consortium C5 for the biodegradation of chlorpyrifos. The 16S rRNA gene-based molecular analysis revealed that the bacterial consortium consisted of Staphylococcus warneri CPI 2, Pseudomonas putida CPI 9 and Stenotrophomonas maltophilia CPI 15. Optimization of chlorpyrifos degradation by the consortium C5, using a Box–Behnken design, was carried out taking into account four important variables: temperature, pH, the initial concentration of chlorpyrifos and time of incubation. C5 is capable of giving 90% degradation of chlorpyrifos (125 ppm) in 8 days of incubation under optimized conditions of pH (7) and temperature (30°C). Growth curve and degradation study under optimized conditions confirmed that consortium could improve the biodegradation potential. From these results, we conclude that the novel consortium C5 of three species can be used to eliminate chlorpyrifos from various environmental compartments and can be implemented in bioreactors in a cost-effective, safe and environmentally friendly manner.

Textural characteristics of taro (Colocasia esculenta L. Schott) cormels during storage at tropical ambient conditions (31.8 to 44.9 °C, 30% to 50% relative humidity [RH]), evaporative cooled room (EC room) (26.2 to 33.9 °C, 59% to 92% RH), and refrigerator (10 °C, 65% RH) and cooking were measured under compression/penetration and cutting modes. After 20 d of storage, physiological loss in weight was maximum at ambient condition followed by EC room and refrigerated condition. The textural parameters (that is, hardness, toughness, cutting force, and cutting energy) significantly increased with storage period whereas effect of storage condition was significant only for toughness and cutting energy (P < 0.001). Most of the rheological characteristics were lowered for the flours prepared from the stored samples. Fractional conversion technique and time step effect parameters were employed to model the kinetics of texture degradation during cooking. The mode of measurement of texture characteristics influenced the kinetic model, that is, cutting force, was described with 1st-order kinetic model and hardness by dual mechanism of 1st order.

Resistant starch is becoming important among functional foods because of its similarity to dietary fiber in many physiological properties. In the present study, an attempt has been made to compare two distinct tuber starches from cassava and potato, in the formation of RS4 type resistant starch by chemical modification with octenyl succinic anhydride (OSA). The octenyl succinate esters of both the starches exhibited significant changes in structural, functional, and dietetic properties in comparison to their respective native counterparts. The modified starches were characterized by FTIR, SEM, and XRD analysis. The pasting, gelatinization, and in vitro digestibility properties were also determined. The water binding capacity of both the starches increased upon modification. The pasting and gelatinization properties of the two starches were affected differently. The cooked samples of octenyl succinylated potato starch showed slowly digestible starch (SDS) and resistant starch (RS) in the range of 10.53–34.86% and 3.58–29.1%, respectively, whereas these were 20.46–38.36% and 1.47–27.92%, respectively, for cassava starch. In both cases, RS and SDS of modified starches increased significantly and glycemic index (GI) decreased in comparison to corresponding native starches.

Alternative agricultural systems, like organic farming, that are less chemical intensive, less exploitative and environment friendly are gaining popularity. Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson) is an important starchy tuberous vegetable with high nutritive and medicinal values. Since information on the organic farming of tuberous vegetables is scanty, field experiments were conducted in this crop at the Central Tuber Crops Research Institute, India, over a 5-year period. The impact of organic, conventional, traditional and biofertilizer production systems on growth, yield, quality, soil physico-chemical properties and economics were evaluated in elephant foot yam. Our results show that organic farming favoured canopy growth, corm biomass and lowered collar rot disease. Dry matter and starch contents of organic corms were significantly higher than those of conventional corms by 7% and 13%, respectively. Organic corms had 12% higher crude protein and 21% significantly lower oxalate contents. The content of K, Ca and Mg in corms were slightly higher, by 3–7% under organic farming. After 5 years of farming, the organic plots showed significantly higher pH, by 0.77 unit, and higher organic C by 19%. The exchangeable Mg, available Cu, Mn and Fe contents were also significantly higher. Organic management lowered the bulk density by 2.3%, improved the water-holding capacity by 28.4% and the porosity of soil by 16.5%. In short, organic farming proved superior and produced 20% higher yield (57.097 t ha−1) over conventional practice (47.609 t ha−1). The net profit was 28% higher and an additional income of Indian Rs. 47,716 ha−1 was obtained. Thus organic farming was found to be an eco-friendly management strategy in elephant foot yam for sustainable yield of quality tubers and higher profit besides maintaining soil health. Technologies for organic production involving farmyard manure incubated with bioinoculants, green manuring, neem cake, biofertilizers and ash were also standardized.

Background In addition to sequence conservation, protein multiple sequence alignments contain evolutionary signal in the form of correlated variation among amino acid positions. This signal indicates positions in the sequence that influence each other, and can be applied for the prediction of intra- or intermolecular contacts. Although various approaches exist for the detection of such correlated mutations, in general these methods utilize only pairwise correlations. Hence, they tend to conflate direct and indirect dependencies. Results We propose RMRCM, a method for Regularized Multinomial Regression in order to obtain Correlated Mutations from protein multiple sequence alignments. Importantly, our method is not restricted to pairwise (column-column) comparisons only, but takes into account the network nature of relationships between protein residues in order to predict residue-residue contacts. The use of regularization ensures that the number of predicted links between columns in the multiple sequence alignment remains limited, preventing overprediction. Using simulated datasets we analyzed the performance of our approach in predicting residue-residue contacts, and studied how it is influenced by various types of noise. For various biological datasets, validation with protein structure data indicates a good performance of the proposed algorithm for the prediction of residue-residue contacts, in comparison to previous results. RMRCM can also be applied to predict interactions (in addition to only predicting interaction sites or contact sites), as demonstrated by predicting PDZ-peptide interactions. Conclusions A novel method is presented, which uses regularized multinomial regression in order to obtain correlated mutations from protein multiple sequence alignments. Availability R-code of our implementation is available via http://www.ab.wur.nl/rmrcm

Cassava or tapioca (Manihot esculenta Crantz) tubers having high amount of carbohydrate are utilized after boiling or processing into starch and flour. Textural properties of raw and cooked tubers depend on variety, maturity, growing environment, physico-chemical and starch properties. Starch is used in food preparations as gelling and thickening agent, stabilizer and texture modifier. This study aims at analyzing and modeling the textural, dynamic rheological and gelatinization properties of selected cassava varieties. The thermal softening behavior was analyzed by linear regression and fractional conversion techniques, rheological properties of the gelated starch by Maxwell and power law models. The varieties were classified based on their physico-chemical, texture profile, rheological and gelatinization properties by multivariate analysis. The textural, rheological and gelatinization properties were significantly affected by the varieties (p 0.05). Thermal softening of tubers was modeled by dual mechanism first order kinetic model with rate constant values ranging from 0.081 to 0.105 min(-1). Linear regression models with extremely good fit were obtained to explain the relationship between the degree of cooking and relative firmness. The dynamic spectra of the gelated starch showed the characteristics of concentrated biopolymer dispersion and described using Maxwell and power law model. The results showed that textural, rheological and gelatinization properties varied considerably among the varieties and besides the physico-chemical properties, interaction between them and structural make up of the tuber parenchyma had a great influence on cooking quality and rheological properties.

Short-duration (6-7 months) cassava provides opportunities to smallholder farmers for effective utilisation of resources such as land, moisture and nutrients as well as diversification of enterprise and income. The variation in biomass production and partitioning, seasonal course of growth indices, yield, quality and nutrient uptake of ten short-duration/early-bulking genotypes of cassava and their impact on nutrient contents in soil in a lowland situation akin to rice fallow were examined in this study.Triploid 2-18 gave the highest yield (38.34 t ha(-1)), followed by triploid 4-2, Sree Vijaya, Sree Jaya and Vellayani Hraswa, which were on a par (30-32 t ha(-1)). Vellayani Hraswa, Sree Vijaya and triploid 4-2 had significantly higher tuberous root dry matter content (370-380 mg g(-1)) and fairly higher starch content (270-280 mg g(-1)). All genotypes except triploid 4-2, triploid 2-18 and H-165 had low cyanogen content (29.2-43.8 microg g(-1)), well within the tolerable limit. Tuberous root dry matter and total dry matter production, crop growth rate, tuberous root bulking rate and harvest index at the last phase, number of tuberous roots, mean weight of tuberous roots and nutrient uptake showed significant positive correlations with tuberous root yield. Principal component analysis also showed a similar trend.The diploids Sree Vijaya, Sree Jaya, Vellayani Hraswa and Kalpaka are ideal for cultivation in rice fallow for food use owing to their high yield, good cooking quality and low cyanogen content. The triploids are better suited for industrial use owing to their high tuberous root dry biomass production.