Showing papers by "Central Tuber Crops Research Institute published in 2016"

Improved sugarcane productivity with tillage and trash management practices in semi arid tropical agro ecosystem in India

Abstract: Sugarcane productivity at the farm level has been stagnant in India, at around 54–72 t ha −1 . One of the main reasons for this low productivity is the yield gap between ratoon and plant cane yield. To improve the ratoon yield and bridge the yield gap, a field experiment was conducted for two seasons with different tillage systems and trash management practices. The treatments in main plots were T1—tillage by tractor drawn off barring (TT), T2—conventional tillage by the bullock drawn country plough (CT) and T3—no tillage (NT) along with seven types of trash management practices (viz., mulching, shredding combined with micro organisms etc.) as sub plots. The results revealed that Tillage by Tractor drawn off barring, (TT) combined with adoption of trash shredding + composted pressmud + wonder life (S4) treatment significantly improved the germination percentage, tiller number, number of millable canes and ultimately the ratoon cane yield in both the seasons. Similarly, soil physical parameters such as bulk density, mean weight diameter, water stable aggregates, soil moisture content were also significantly influenced by the above treatment when compared to control. Besides, root weight of cane, quality parameters of cane juice, soil available N and P, organic carbon, microbial biomass carbon and arbuscular mycorrhizal fungi (AMF) population also were significantly improved by the adoption of tillage and trash management practices. The results suggest that the tillage with adoption of trash management practices assisted in improving the profitability by way of higher sugarcane ratoon productivity and also in sustaining the soil fertility.

Rock inhabiting potassium solubilizing bacteria from Kerala, India: characterization and possibility in chemical K fertilizer substitution.

Abstract: The role of rock inhabiting bacteria in potassium (K) solubilization from feldspar and their application in crop nutrition through substitution of fertilizer K was explored through the isolation of 36 different bacteria from rocks of a major hill station at Ponmudi in Thiruvananthapuram, Kerala, India. A comprehensive characterization of K solubilization from feldspar was achieved with these isolates which indicated that the K solubilizing efficiency increases with decrease in pH and increase in viscosity and viable cell count. Based on the level of K solubilization, two potent isolates were selected and identified as Bacillus subtilis ANctcri3 and Bacillus megaterium ANctcri7. Exopolysaccharide production, scanning electron microscopic and fourier transform infrared spectroscopic studies with these efficient strains conclusively depicted the role of low pH, increase in viscosity, and bacterial attachment in K solubilization. They were also found to be efficient in phosphorus (P) solubilization, indole acetic acid production as well as tolerant to wide range of physiological conditions. Moreover, the applicability of K containing rock powder as a carrier for K solubilizing bacteria was demonstrated. A field level evaluation on the yield of a high K demanding tuberous vegetable crop, elephant foot yam (Amorphophallus paeoniifolius (dennst.) nicolson) established the possibility of substituting chemical K fertilizer with these biofertilizer candidates successfully.

Gluten-free starch noodles from sweet potato with reduced starch digestibility and enhanced protein content

Abstract: Sweet potato starch (SPS) noodles despite being gluten-free, has low nutritional value as it lacks proteins, minerals, vitamins etc. The objective of this study was to develop gluten-free starch noodles from sweet potato with enhanced protein content through fortification with whey protein concentrate (WPC) and to study the effect of protein fortification and blending SPS with banana (BS), cassava (CS) and mung bean (MBS) starches and annealed cassava starch (ACS) in reducing the starch digestibility. The highest protein retention in cooked noodles was obtained for 20 % WPC fortification, while the lowest starch digestibility was observed for 40 % BS fortified noodles followed by 50 % ACS fortified noodles. The highest resistant starch (RS) retention was for BS and ACS fortified noodles, which also had medium glycemic index of 66.3 (BS) and 67.2 (ACS). High sensory scores were obtained for the BS and 20 % WPC fortified noodles. The study showed that protein and/or BS fortification with SPS could enhance the acceptability as well as functional value of SPS noodles.

Optimization of Chlorpyrifos Degradation by Assembled Bacterial Consortium Using Response Surface Methodology

Abstract: 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 i...

Application of QUEFTS Model for Site-Specific Nutrient Management of NPK in Sweet Potato (Ipomoea batatas L. Lam)

Abstract: Sweet potato productivity in India is either stagnated or lowering down over the past many years. The main reasons for low yield are conventional blanket recommendation of fertilizers, lower nutrient-use efficiency and imbalance in the use of fertilizers. Recommendation of major nutrients, nitrogen, phosphorus, and potassium (NPK), based on quantitative approaches will augment sweet potato production per unit area by increasing the nutrient-use efficiency. The present study calibrated the Quantitative Evaluation of Fertility of Tropical Soils (QUEFTS) model for the estimation of NPK requirements and fertilizers recommendations for different target yields of sweet potato. The QUEFTS basically works on the principle of NPK nutrient interactions and climate-adjusted yield potential of a region. Published data sets from several field experiments related to NPK carried out till date were collected to reflect the environment variability. The results of the present study showed that to produce one ton tu...

Ectopic expression of amaranth seed storage albumin modulates photoassimilate transport and nutrient acquisition in sweetpotato.

Abstract: Storage proteins in plants, because of high nutrient value, have been a subject of intensive investigation. These proteins are synthesized de novo in the cytoplasm and transported to the storage organelles where they serve as reservoir of energy and supplement of nitrogen during rapid growth and development. Sweetpotato is the seventh most important food crop worldwide, and has a significant contribution to the source of nutrition, albeit with low protein content. To determine the behaviour of seed storage proteins in non-native system, a seed albumin, AmA1, was overexpressed in sweetpotato with an additional aim of improving nutritional quality of tuber proteins. Introduction of AmA1 imparted an increase in protein and amino acid contents as well as the phytophenols. The proteometabolomics analysis revealed a rebalancing of the proteome, with no significant effects on the global metabolome profile of the transgenic tubers. Additionally, the slower degradation of starch and cellulose in transgenic tubers, led to increased post-harvest durability. Present study provides a new insight into the role of a seed storage protein in the modulation of photoassimilate movement and nutrient acquisition.

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.

Site-Specific Nutrient Management for Cassava in Southern India

Abstract: Cassava (Manihot esculenta Crantz.) yield in the major growing environments of India has been stagnating despite the development of high yielding varieties and increasing use of chemical fertilizers. On farm experiments were conducted to evaluate the performance of site-specific nutrient management (SSNM). Field and crop specific NPK rates were calculated using quantitative evaluation of fertility of tropical soils (QUEFTS) model. The average 2-yr yield advantage of SSNM over farmer fertilizer practice (FFP) was 7 Mg ha–¹. The N agronomic efficiency increase of SSNM over FFP was 32 kg kg–¹, the N recovery efficiency of SSNM was 0.14 kg kg–¹ greater than that of FFP and the N physiological efficiency of SSNM was 54 kg kg–¹ greater than that of FFP, whereas the partial factor productivity of SSNM was 148 kg less than that of FFP. Use of SSNM led to a reduction of fertilizer costs by an average of US$10 ha–¹ crop–¹ and an increase in gross return above fertilizer costs by $254 ha–¹ crop–¹ compared with FFP. Zone NPK recommendation maps and customized fertilizer blends were also developed. The results showed the potential of SSNM in significantly increasing yield and nutrient use efficiency of cassava. Future research is needed to validate the customized fertilizer blends and fine tune zone NPK recommendation maps which will help reduce the need for field specific modeling and intensive crop monitoring.

Molecular characterization and amplified ribosomal DNA restriction analysis of entomopathogenic bacteria associated with Rhabditis (Oscheius) spp.

Abstract: Bacterial strains associated with entomopathogenic nematodes (EPNs) Rhabditis (Oscheius) spp. were isolated from infected cadavers of Galleria mellonella. The obtained 18 isolates were subdivided into nine phylogenetically different genera based on comparative sequence analysis of their 16S rRNA genes. The isolates were affiliated to three different class namely γ-proteobacteria (Enterobacter, Proteus, Providencia, Pseudomonas, Stenotrophomonas), β-proteobacteria (Alcaligenes) and Bacilli (Bacillus, Enterococcus, Lysinibacillus). It was observed that Gram-positive strains (Bacilli) were more frequently associated with the EPN, whereas Gram-negative isolates were affiliated to six different genera with more genotypic diversity. Subsequently, all bacterial isolates used in this study were analyzed by amplified ribosomal DNA restriction analysis (ARDRA). Eight restriction endonucleases (CfoI, HinfI, RsaI, DdeI, Sau3AI, AluI, HaeIII, and MspI) were examined and a total of 15 different genotypes were obtained, forming two heterogenous main clusters after analysis by un-weighted pair-group method using arithmetic averages.

A Rapid and Efficient Method for In Vitro Screening of Taro for Leaf Blight Disease Caused by Phytophthora colocasiae

Abstract: Taro leaf blight caused by Phytophthora colocasiae presents the single biggest constraint for taro cultivation globally. To accelerate breeding and selection for disease resistance to leaf blight, it is important to develop bioassays which could differentiate resistant and susceptible cultivars efficiently. In this study, thirty taro accessions and four released cultivars were evaluated for resistance to leaf blight using a modified floating leaf disc assay. A novel method for mass production of P. colocasiae zoospores was developed and used as inoculum for the assay. There were significant (P < 0.05) differences among accessions in their response to P. colocasiae infection in the detached leaf assay. The accessions could be efficiently classified into various resistance groups based on a 0–4 score. Also, the assay results were consistent with the field evaluation scores of taro accessions. Thus, this study reports the development of a rapid, simple and repeatable assay that can be used to screen large numbers of taro cultivars for resistance to P. colocasiae.

INDO-BLIGHTCAST – a model for forecasting late blight across agroecologies

Abstract: A late blight forecasting model “INDO-BLIGHTCAST” has been developed at the Central Potato Research Institute, Shimla, India using meteorological data and late blight appearance dates at four locations in the Indo-Gangetic plains. The model involves computation of physiological days (P-days) and mean relative humidity (RH) of the night, accrued over seven consecutive days. Late blight was predicted to appear within 15 days if moving cumulative effective temperature (P-days) and RH exceeded 52.5 and 525, respectively for seven consecutive days. The developed model was also tested against independent data sets at three locations in the plains, two in plateau region and three in the hills. Statistical comparisons of observed and predicted dates of late blight appearance showed that the mean absolute error was 10.48, while the residual mean square error was only 13.17 indicating that the errors were quite low. The Willmott D index was 0.84 which is quite close to unity thus indicating high accuracy of...

Chitosan and Starch-Based Hydrogels Via Graft Copolymerization

Abstract: Graft copolymerization is an attractive method for surface functionalization of natural polymers and can be initiated by chemical methods, radiation technique, and other systems. Polymer grafting onto polysaccharides is an effective method for the synthesis of superabsorbents. Depending upon the type of monomers and the conditions employed the properties of graft copolymers vary to a large extent. Chitosan is a nontoxic, biocompatible polysaccharide, and starch is a natural hydrophilic biopolymer. Both these are most abundant natural organic materials which are extensively investigated in the development of biodegradable and environment-friendly materials. Their hydrogels are of utmost importance for wide use in many fields including structural transplants, target drug delivery, tissue engineering, biosensors, adsorbents, etc. In this chapter, the various techniques used for the synthesis of chitosan/starch graft copolymers, their properties and possible applications are discussed in detail.

Development of taro ( Colocasia esculenta (L.) Schott) hybrids overcoming its asynchrony in flowering using cryostored pollen

Abstract: Taro (Colocasia esculenta (L.) Schott) is an important root crop and vegetable across tropics and subtropics of the world. Conventional breeding of taro is hindered due to asynchrony in flowering owing to functional, structural barriers associated with flowering behaviour. An attempt was made to tackle asynchronous behaviour in taro by preserving pollen. The present study was therefore undertaken to cryostore taro pollen at different time intervals ranging from 1 week to 2 months and to use the cryostored pollen for hybridization of exotic taros introduced in India. Fruit setting was observed within a week of hybridizing exotic taros with cryopreserved pollens. Seeds extracted from different combinations were characterized. Seed germination in vitro was recorded in the range of 60–90 % among the seeds of different parental combinations. In vitro seedlings transplanted, hardened and established in screen house are now under field evaluation for early maturity and blight resistance. These results will improve planned hybridization in asynchronous flowering type aroids like taro and will contribute to recover desirable hybrids with the aid of cryopreservation tools.

Response of Mycorrhiza, Organic Sources, Secondary and Micro Nutrients on Soil Microbial Activities and Yield Performance of Colocasia (Colocasia esculenta L.) in Alfisols

Abstract: Response of the integrated use of mycorrhiza, inorganic and organic manures on microbial variables and yield performance of colocasia (Colocasia esculenta L.) was studied in an acid Alfisol. Significantly highest mean cormel yield (14.13 t ha−1) was recorded due to application of super optimal doses of nitrogen, phosphorus, and potassium (NPK). Integrated application of lime + farmyard manure (FYM) + ½ NPK + zinc sulfate (ZnSO4) has recorded the highest dehydrogenase activity (2.048 µg TPF hr−1 g−1) and Fluorescein Diacetate Hydrolysis assay (1.855 µg g−1 hr−1). The highest acid and alkaline phosphatase activities (77.67 and 51.18 µg PNP g−1 h−1, respectively) were observed due to Vesicular Arbuscular Mycorrhiza (VAM) inoculation in combination with lime + FYM + ½ NPK. Dehydrogenase and phosphatase activities had a highly significant relationship with cormel yield and the biochemical constituents of colocasia. The study emphasized the conjunctive use of balanced inorganic fertilizers and organic m...

Development and validation of LC—ESI—MS/MS method for simultaneous determination of four coumarin derivatives and an alkaloid from root and stem bark of Aegle marmelos Correa

Abstract: Aegle marmelos Correa (Bael tree) is a medicinal fruit tree, widely used for healing purposes in various systems of medicines. Coumarins and alkaloids present in various parts of bael tree including roots and fruit pulp are the primary active constituents implicated for its biological activities. An efficient liquid chromatography–electrospray ionization—tandem mass spectrometry (LC—ESI—MS/MS) method was developed for identification and simultaneous determination of four coumarin derivatives, namely, umbelliferone, psoralene, marmin, and imperatorin, and an alkaloid, skimmianine, in root and stem bark of A. marmelos. The chromatographic separation of analytes was performed on Altima C18 (50 × 4.6 mm, 3 μm) column using methanol and 0.1% acetic acid in water (54:46, v/v) as the mobile phase under isocratic conditions. The LC–MS/MS parameters were optimized in the positive ionization mode using electrospray ionization source. The quantification of the analytes was performed using multiple reaction monitorin...

In Vitro Evaluation of the Antioxidant, 3,5-Dihydroxy-4-ethyl-trans-stilbene (DETS) Isolated from Bacillus cereus as a Potent Candidate against Malignant Melanoma.

Abstract: 3,5-dihydroxy Q1 -4-ethyl-trans-stilbene (DETS) is a natural stilbene, which was first identified as bioactive bacterial secondary metabolite isolated from Bacillus cereus associated with a rhabditid entomopathogenic nematode. The present study was intended to investigate the antioxidant and anticancer activity of this compound in vitro. Antioxidant activity was investigated by assaying DPPH free radical scavenging, superoxide radical-(O2..) scavenging, hydroxyl radical scavenging and metal chelating activity, which proved that the compound is a powerful antioxidant. The metal chelating activity of DETS was higher than butylated hydroxyanisol (BHA) and gallic acid, two well-known antioxidants. As the molecule exhibited strong antioxidant potential, it was further evaluated for cytotoxic activity toward five cancer cells of various origins. Since the compound has a strong structural similarity with resveratrol (trans- 3,4,5-trihydroxystilbene), a well-studied chemopreventive polyphenolic antioxidant, its anticancer activity was compared with that of resveratrol. Among the five cancer cells studied, the compound showed maximum cytotoxicity toward the human melanoma cell line, [A375, IC50: 24.01 μM] followed by cervical [HeLa-46.17 μM], colon [SW480- 47.28 μM], liver [HepG2- 69.56 μM] and breast [MCF-7- 84.31 μM] cancer cells. A375 was much more sensitive to DETS compared to the non-melanoma cell line, A431, in which the IC50 of the compound was more than double (49.60 μM). In the present study, the anticancer activity of DETS against melanoma was confirmed by various apoptosis assays. We also observed that DETS, like resveratrol, down-regulates the expression status of major molecules contributing to melanoma progression, such as BRAF, β-catenin and Brn-2, all of which converge in MITF-M, the master regulator of melanoma signaling. The regulatory role of MITF-M in DETS-induced cytotoxicity in melanoma cells was confirmed by comparing the cytotoxicity of DETS in A375 cells (IC50-24.01 μM), with that in SK-MEL-2 (IC50-67.6 μM), another melanoma cells which highly over-express MITF-M. The compound arrests the cells at S-G2 transition state of the cell cycle, as resveratrol. Our results indicate that DETS is a powerful antioxidant, having anticancer efficacy comparable with that of resveratrol, and is a potential candidate to be explored by in vivo studies and in-depth mechanistic evaluation. To our knowledge, this is the first report on the antioxidant and anticancer properties of DETS.

Evaluation of dry matter, starch content and β-carotene in F1 progenies of a cross between white fleshed and orange fleshed sweet potato

Abstract: Sweet potato ( Ipomoea batatas (L.) Lam.) is one of the valuable crops producing the highest root dry matter content for human consumption. Sweet potato breeding is very challenging due to its genetic complexity. The tuber flesh colour variation ranges from white, cream, yellow, orange and purple. High dry matter content, carotene and anthocyanins are the main tuber characters preferred by consumers and processors. In this study, a population consisting 200 F 1 progenies from a cross of S-1 (white fleshed) and ST-14 (orange fleshed) were analyzed for dry matter, starch and β-carotene content. The dry matter content of the progenies ranged from 18.58% (OW48) to 45.7% (OW15) and 30 per cent of the progenies showed dry matter content of 35 - 40%. The starch content accounted variations from 9.80 to 32.7 per cent and only 9 per cent showed starch content above 30%. Among the progenies, the β-carotene ranged from 0.02 – 11.03 mg/100g FW. The progenies OW4, OW27, OW37, OW43, OW126 and OW169 recorded the highest dry matter, β-carotene as well as high starch content. The tuber flesh colour variation in the progenies was done phenotypically based on 1 - 6 score. Among the progenies orange flesh colour was predominant and from the OFSP progenies, the most predominant tuber flesh colour observed was light orange (28%), orange (22%) and deep orange (4%) colour respectively.

Electrophysiological and Behavioural Responses of Sweetpotato Weevil, Cylas formicarius Fab. to Sweetpotato Varieties

Abstract: Electrophysiological and behavioural studies coupled with field experiments were conducted to analyse the olfactory responses of sweetpotato weevil (SPW), Cylas formicarius Fab. to six varieties of sweetpotato, in order to understand how the olfactory system of the weevil distinguishes between volatiles from the susceptible and resistant varieties. Female SPW recorded significantly highest attraction (P < 0.01) towards 'Kishan' volatiles and lowest towards 'Gouri'. SPW infestation was highest in 'Kishan' (82.33%), whereas it was lowest in 'Gouri' (33.73%) at field level. A greater electrophysiological response was recorded by male and female SPW antenna to leaf and flower volatiles respectively. Males showed higher depolarization (amplitude) and lesser recovery time compared to females, particularly to leaf volatiles. The comparative study of electroantennographic analysis, olfactometry and infestation data indicated that 'Kishan' is the most susceptible variety, attracting a large number of weevils; while 'Gouri', is the resistant variety.

The influence of different pre-treatments on enhancing seed germination in cassava

Abstract: Cassava is propagated through vegetatively by stem cuttings. However, cassava sexual seeds are widely used by the breeders with the objective of developing new variety with its adaptibity in varying environmental conditions, disease resistance and high yield. But the limiting factors like hard seed coat, light, temperature and other intrinsic factors leads to poor seed germination rate. The aim of this study was to enhance and obtain early seed germination in cassava, which takes 16 to 20 days under normal condition. The efficacy of different treatments like mechanical scarification, water treatment and Gibberellic acid was investigated. It was found that seed germination percentage was significantly varied among different treatments (p<0.01) and maximum seed germination at 7 th day after treatment was observed for 50 ppm gibberellic acid treatment (T 5 ), followed by 60ppm gibberellic acid for 30 minutes on cotyledons (T 14 ). By comparing the results, 50ppm GA 3 , overnight soaked seeds (T 5 ) had significant effect on germination (66.67 %) and can be used as a best treatment for getting early germination in cassava before 10 days.

Identification of disease resistance genes in cassava using NBS transcriptome profiling

Abstract: Cassava production is seriously affected by cassava mosaic disease (CMD) and is one of the most important problems in India and Africa. The disease can be kept under control by deploying resistance genes through marker assisted selection (MAS). Nucleotide Binding Site (NBS) profiling is a motif directing profiling technique specifically targets chromosomal region containing resistance genes (R) and produce markers tightly linked withR-genes. The present study aims to target disease resistance (R) genes in cassava using NBS transcriptome profiling technique. For this purpose, two cassava varieties viz., MNga-1 (resistant variety) and CI732 (susceptible variety) were selected on the basis of CMD resistance and generated reproducible polymorphic multi-locus banding pattern with NBS prmers (NBS2 &NBS5). The polymorphic bands present in the resistant variety were eluted and directly sequenced using ABI3500 automated sequencer. The functional annotations of the sequences were carried out in both Phytozome v10 and NCBI using blastn program and RCa6 gene, non-specific lipid-transfer protein (ns-LTPs) and heat shock proteins (Hsp 90, Hsp 89-1, Hsp 81.2) involved in plant defense against cassava mosaic virus and its insect vector whitefly.

Characterization of mealy substance secreted by the tuber crops pest mealy bug, Rhizoecus amoprhophalli

Abstract: Rhizoecus amorphophalli is a polyphagous and very serious sucking insect pest on the root and tuber of plants. White powdery mealy substance associated with R. amorphophalli, gives protection to the insect. Mealy substance was isolated using a stereo zoom binocular microscope. Purity of the mealy substance was analysed using High-Performance Liquid Chromatography and Thin-layer chromatography. The structure of mealy substance was determined based on extensive spectroscopic analyses (FTIR, 1H NMR, 13C NMR). Based on the NMR data, the mealy substance was identified as a long-chained aliphatic hydrocarbon (ester) containing 30 carbon atoms.