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Open Access
Institutional intervention in marketing of non-timber forest products (NTFPs) in Kerala
(Department of Rural Marketing Management, College of Co-operation, Banking and Management, Vellanikkara, 2023-05-13) Vijayakumar, N; KAU; Ushadevi, K N
Indigenous communities living in the forests depends on the forest resources like Non-Timber Forest Products (NTFPs) for their survival and livelihoods. The dominance of the middlemen, lack of accessibility of the market and lack of awareness of the price of NTFPs were the main problems faced by tribals in the collection and marketing of NTFPs (Rawal, 2020). There is a growing market for NTFPs, but its large potential still needs to be tapped by both the collectors and the institutions involved. Since efforts have been going on for quite a long time, new agencies and institutions, have been established and programmes and schemes have been implemented to promote the NTFPs and thereby develop the tribal community. It is time that an assessment of these interventions be done to assess whether these interventions are within reach of the tribals, to what extent the policy measures of central and state government have positively affect the marketing of NTFPs and the livelihood of tribes collecting NTFPs, whether the institutions address the problems faced by the tribals and to what extent they succeeded in solving the issues related to marketing of NTFPs. In this context the present study entitled ‘Institutional intervention in marketing of Non-Timber Forest Products (NTFPs) in Kerala’ was undertaken to analyse the existing market structure of NTFPs, to examine the role of institutional intervention in promoting NTFPs, to examine the extent of awareness, accessibility and impact of institutional interventions among selected tribes and to analyse the problems faced by the selected tribes in the collection and marketing of NTFPs. This study will fulfil the research gap of the institutional contributions towards improving the livelihood of NTFPs collectors and would help the institutions to identify and prioritise the areas in need of their interventions. Both primary and secondary data were collected for the study. As per the data collected from the records of Scheduled Tribes Service Cooperative Society (STSCS) (2018-2019), it was found that Irular, Kattunayakan, Paniyan, and Kadar were the tribes mainly engaged in the collection of NTFPs. Among them Kattunayakan and Paniyan tribes are settled in Wayanad district, Irular tribe is settled in Palakkad district and Kadar tribe is mainly settled in Thrissur district. Through stratified random sampling method, 204 tribals collecting NTFPs, from these four tribes were selected. With respect to the selection of institutions, all the categories of the institutions involved in promoting NTFPs collectors based in Kerala state were selected with a total sample size of 12 viz Kerala Forest and Wildlife Department (KFD), STSCS, Tribal co-operative Marketing Development Federation of India (TRIFED), Kerala State Federation of SC/ST Development Cooperative Ltd (SC/ST Federation), Scheduled Tribes Development Department (STDD), Kerala State Development Corporation for Scheduled Castes and Scheduled Tribes (KSDC-ST/SC), College of Forestry (CoF), Kerala Institute for Research Training and Development Studies for SC & ST (KIRTADS), Kerala Forest Research Institute (KFRI), Kerala Forest Development Corporation (KFDC) and National Afforestation and Eco-Development Board (NAEDB). Data from tribals were collected through Participatory Rural Appraisal (PRA) method, by using semi-structured interview schedule. Primary data from the institutions were collected from officials of the institutions by using pre-tested structured interview schedule. Secondary data were collected from annual reports, and official websites of selected institutions. Percentage analysis, pair-wise ranking and seasonal calendar were used to analyse the existing market structure of NTFPs. The role of institutional interventions in promoting NTFPs was examined with the help of Venn Diagram. Awareness was examined with the help of percentage analysis. Mobility Map and Impact Diagram were used to examine the accessibility and impact of institutional interventions respectively. Problems of tribals were identified by using Garret Ranking and by drawing ranking ladder. From the analysis of existing market structure of NTFPs in Kerala, it was found that tribals, SC/ST Federation, STSCS, TRIFED, and KFD are the major players in the market. In addition to this the presence of institutions like STDD, KSDC SC/ST, CoF, KIRTADS, KFRI are also found in promoting NTFPs through conducting training, workshops, exhibitions, promoting NTFPs through social media etc. Tribal community are the sellers and STSCS, KFD and TRIFED are the main buyers. A common market structure for NTFPs does not exist in Kerala .An oligopsony market structure was identified where institutions were present and monopolistic competition was observed in the absence of institutions in certain tribal settlements. The STSCS main activity is regularly procuring NTFPs from tribals and marketing NTFPs with the help of the SC/ST Federation through auction cum quotation and negotiation. Eco-Development Committees (EDC) and Vana Samrakshana Samithi (VSS) of KFSD collect NTFPs from tribals and market through Vanasree eco shops, Vanasree e-portal and exhibitions under the brand name Vanasree. Institutions provide a pool of information to help the tribals to undertake their operations more systematically and scientifically. Majority of the tribals prefer to sell the collected NTFPs to STSCS. They had expressed, better price, spot payment, flexible payment options, bulk procurement and regular consumers as the reasons for preferring STSCS over other institutions. Among the institutions TRIFED offers an effective product differentiation support. TRIFED had trained the tribals to produce seven value added products from honey. KFD have an effective supply chain logistics which facilitates the prompt delivery of the product to the customers. . Majority of the tribal community consider KFD, CoF, STDD, and STSCS as important institutions. Out of these they considered STSCS as effective in rendering the service. Institutions had provided product development and market development supports to tribals in additions to the implementation of various schemes of the central and state government. However, the services and supports of the institutions are not benefitting the tribals to the expected level due to their low level of awareness The awareness of the tribals with respect to the interventions of the institutions are very low as they had not received any awareness programme on services offered by the institutions till now. The officials from the majority institutions were not visiting the colony and disseminating the necessary information to the tribals. Most tribals mentioned the forest office, STSCS, and its depot as being conveniently accessible to them. Many institutions that assisted NTFPs collectors (tribals) were far away from the colony, making it difficult for them to access these institutions. The study brought out that institutional interventions had resulted in increasing tribals income, reducing school dropouts, increasing the number of women collectors, reducing tribals debt, and tribals migrations. The major problems faced by the selected tribals with respect to collection of NTFPs were negative interactions with wild animals, inadequate availability of NTFPs in the forest and low price availability of NTFPs. Lack of guidance and support from government officials for marketing of NTFPs, no institutional support/follow up after training programme and long distance to market place cause considerable interruption in marketing of NTFPs. The study brought out the need for certain policy interventions which will help to improve the lively hood of NTFPs collectors. Many marketing channels exist in Kerala for marketing NTFPs and the procurement price and selling price differs based on the channels. If a uniform marketing channel can be created uniform pricing of the NTFPs would be possible.. Even though most of the selected institutions were conducting training programme the intended benefits are not reaching to tribal communities due to the lack of follow up measures. It would be better if institutions arrange follow-up programmes and making monthly visit to tribal settlements. This would help them to sell NTFPs as value added products and build a good relationship with the institutions. As the tribals were unaware of much information, the timely communication of various programmes, services and implementation of schemes etc is necessary. Institutions should take utmost care in this respect. It is difficult for tribals to access the services of institutions, as tribals were situated far away from the institutions and they don’t have vehicle or public transport services. Therefore, it is suggested that institutions should visit the colony monthly to provide their services and identify the problems of the tribals. Inadequate availability of NTFPs in the forest will make a negative impact in their collection and income. Arrangement for clearing the forest every month from the part of the Forest Department will help to address this issue. Addressing these suggestions will help to make the existing interventions of institutions more effective and bring out better reflection on the socio economic upliftment of tribals in Kerala.
Open Access
Identification of genetic stock for drought tolerance and candidate gene analysis in cocoa(Theobroma cacao L.)
(Department of plantation,spices,medicinal and aromatic crops, college of agriculture ,Vellanikkara, 2023-09-21) Suchithra, M.; KAU; Suma, B
Water deficit stress is considered as one of the most limiting factor for production in cocoa. Preliminary efforts have been made in Kerala Agricultural University to identify drought tolerant cocoa genotypes. The present study was an attempt made to identify the cocoa genotypes and hybrids that can tolerate drought condition. The study was conducted at Department of Plantation crops and spices, College of Agriculture (CoA) and Cocoa Research Centre and College of Agriculture, Vellanikkara, Thrissur. Thirty exotic genotypes and six pre-released hybrids were taken as materials for the study. They were budded on 6 month old rootstock of seedling raised from polyclonal gardens. GIV 18.5 (progeny of pods from Nileshwar) identified susceptible genotype was used as check in the experiment. Five month old budded plants of thirty exotic cocoa genotypes and six hybrids along with check variety were subjected to drought screening by following gravimetric method. Control plants were maintained at fully irrigated condition under 100 per cent field capacity. Field capacity was maintained at 40 per cent for stress condition. Based on the percentage of retained leaves genotypes and hybrids were categorised as highly tolerant (more than 70% leaves retained), tolerant (40-70% leaves retained), susceptible (10-40% leaves retained) and highly susceptible (less than 10% leaves retained). Various physiological and biochemical parameters related to drought were analyzed. The physiological parameters, relative water content, chlorophyll stability index, membrane stability, photosynthetic rate and chlorophyll content were recorded high in tolerant and highly tolerant genotypes and hybrids whereas these parameters were comparatively low in susceptible and check variety. The control plants at 100 per cent field capacity recorded high value for all these parameters. However in terms of transpiration rate a reverse trend was observed among genotypes and hybrids. Low transpiration rate was recorded in highly tolerant and tolerant hybrids whereas ii susceptible genotypes and hybrids had high transpiration rate under stress condition. The control plants under fully irrigated condition of 100 per cent field capacity also had high transpirational rate. This indicated the ability of tolerant genotypes and hybrids to conserve water during stress. The leaf temperature did not shown any significant variation among the genotypes and hybrids studied under both the field capacity level. In case of biochemical parameters, proline content, glycine betaine content and superoxide dismutase activity were found to be high in tolerant and highly tolerant genotypes and hybrids and was low in susceptible and check variety. The control plants kept under 100 per cent filed capacity level shown less values for all these parameters. However, all the plants showed reduced nitrate reductase activity under drought stress. The control plants recorded high nitrate reductase activity at 100 per cent field capacity level. Correlation studies showed that all physiological and biochemical parameters except transpiration rate and leaf temperature have positive correlation with percentage of leaves retained. Effect of these parameters on percentage of leaves retained was estimated using path analysis. Parameters having direct effect on leaf retention were proline, nitrate reductase activity, SOD, glycine betaine, cell membrane stability and relative water content. These characters were analyzed for their genetic parameters and it was found that all these characters are having high heritability and genetic gain. D 2 statistics analysis revealed that the 30 genotypes and 6 hybrids along with check were grouped into 6 clusters indicating the presence of diversity for different traits. Four different isolation methods were compared in this experiment to identify the best method that could produce high-quality total RNA free from contaminants and genomic DNA. RNA obtained through the SDS- tertiary butanol method (Gesteira et al., 2003) has high quantity and quality, followed by the modified SDSphenol method (Deepa et al., 2014) in both fresh and frozen leaves. iii The transcriptome of highly drought tolerant exotic genotype (T85/799) and highly drought sensitive check variety CCRP 5 was analysed using mRNA sequencing under control (100% FC) and drought stress condition (40% FC). Drought has up-regulated 1540 and 1148 DEGs and downregulated 1502 and 1250 DEGs respectively in tolerant and sensitive libraries. The PCA scatter plot shows that replicates of the well watered samples (control) of highly drought tolerant genotype and drought susceptible check variety CCRP 5 form distinct groups highlighting differences between the two genotypes. Volcano plot depicted the significance of differentially expressed genes in control and drought stress treated samples of highly tolerant and susceptible genotype. In both the tolerant and susceptible genotypes, the majority of the genes within the biological process category were linked to GO terms that fall under the subcategories of "metabolic process," "cellular process," and "single organism process." “Enzyme catalytic activity”, “water channel activity”, “binding” and “transporter activity” were the most abundant terms in molecular function category in both the genotypes under stress. There were 17 pathways significantly enriched (FDR-adjusted p-value < 0.05) in tolerant genotype for upregulated genes and the most enriched pathways including metabolic pathways (178 genes) followed by biosynthesis of secondary metabolites (121 genes), phenyl propanoid biosynthesis (29 genes), carbon metabolism (29 genes), glyoxylate and decarboxylate metabolism (16 genes), MAPK signalling pathway plant (14 genes) and starch and sucrose metabolism etc. Most of the Transcription Factors (TFs) identified families were enriched in, B3, bHLH, WRKY, ARF, ARR B, FAR, LBD, MADS and ERF. These TFs could be grouped into 10 families. The major upregulated genes families in tolerant genotype includes protein kinase, protein phosphatase type 2c, zing finger proteins, laccase gene, cytokinin dehydrogenase, cytochrome p450, galactinol synthase, NAC Domain protein, peroxidase, protein ubiquitin E3 ligase, mannitol dehydrogenase, fatty acid desaturase, UDP glycosyl transferase, Aquaporin PIP, Glutathione dependent genes, iv cellulose synthase and heat shock proteins etc.The major upregulated genes families in susceptible genotype includes LEA protein, PSII protein, peroxisomal membrane proteins, ABC transporter, ABA hydrolyse, phenyl alanine n-monoxygenase, tyrosine carboxylase, plastocyanin, trehalose phosphate phosphatase and expansin etc. RNA-Seq analysis showed that highly drought tolerant exotic genotype (T85/799) activated more number of drought responsive genes than drought sensitive check variety CCRP 5. Several drought-responsive genes were upregulated in the tolerant genotype such as those encoding TFs, cytochrome 450, and membrane transporters, and those associated with carbohydrate metabolism and flavonoid biosynthesis. These genes might confer drought tolerance in this cocoa genotype at the molecular level. Identified drought- responsive genes and metabolic pathways were targets for future studies in order to understand the molecular mechanism of drought tolerance in cocoa. Physiological and biochemical parameters also indicated the better performance of the tolerant genotype over the susceptible genotype under drought stress conditions. These results were a first step to understanding the molecular mechanisms of drought tolerance in cocoa and lay a foundation for its genetic improvement.
Embargo
Genetic diversity analysis for nutrient efficiency and identification of nutrient responsive genes in cassava (Manihot esculenta Crantz)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2023-02-10) Swathy Sivan; KAU; Arya, K
The present study entitled “Genetic diversity analysis for nutrient efficiency and identification of nutrient responsive genes in cassava (Manihot esculenta Crantz)” was carried out in the Department of Plant breeding and Genetics, College of Agriculture, Vellayani and Division of Crop Improvement, ICAR-CTCRI, Sreekariyam, during 2019-2022. The study was undertaken to screen and characterize N and K-efficient genotypes in cassava and identify the traits contributing to nutrient efficiency and study their gene expression. Thirty genotypes of cassava comprising of landraces, released varieties and pre-release accessions from ICAR-CTCRI and KAU were taken for the study. Field evaluation was done to identify low input nutrient efficient lines where analysis of variance revealed significant difference among the genotypes for all the characters studied except the girth of tuber. High GCV, PCV, heritability and genetic advance were observed for traits like tuber yield, N and K efficiency, plant height, number of leaves, number of branches, stem N and K content. Tuber yield was positively correlated to N and K efficiency, plant height, leaf and stem weight, stem girth, mean weight of tubers, number of nodes, girth and length of tubers, while negatively correlated to tuber starch and dry matter content. Path analysis showed that tuber length gave highest positive direct effect on yield followed by number of tubers, number of leaves, tuber starch content, plant height and nitrogen efficiency. Diversity studies grouped the genotypes into eleven clusters and the characters that gave the maximum contribution to divergence were tuber dry matter content, N and K efficiency. Root studies on thirty genotypes revealed that root traits like number of nodal roots, basal roots, adventitious roots, storage roots and root length displayed significant positive correlations with N and K efficiency. Evaluation of five highly nutrient efficient genotypes at the three levels of fertilizers (0%, 25% and 50% of the recommended dose of fertilizers) showed overall significance for traits like plant height, the number of leaves retained, stem weight per plant, girth of the stem, tuber yield, length of tuber, stem K content, tuber K content, total N and K uptake, N and K efficiency. The highest yielder was KBH 18 followed by 8S501-2. Maximum N efficiency was observed for KBH18 followed by 15S409, while maximum K efficiency was recorded for 8S501-2 followed by 15S409. Results showed that from 0 to 25 % there is an escalation in tuber yield as well as N and K efficiency, while the values at 25 and 50% are on par. All the selected four genotypes showed significant superiority over the K efficient check variety – Sree Pavithra – in terms of tuber yield, N efficiency and K efficiency. The study identified nine nutrient responsive genes in cassava which includes NRT1, NRT3, NLP1, GPT2, AMT1, TAR2 for nitrogen and KUP3, KUP4, KUP8 for potassium. Expression studies done using these genes in contrasting genotypes for N and K efficiency raised under field conditions showed significant upregulations and downregulations in their expression for efficient and less efficient genotypes. Allele mining for allelic variations in contrasting genotypes (15S409 and Export kappa) for two genes (AMT2 and NTR3) didn’t show much significant variation. Although SNP differences were observed for NRT3 gene, further functional studies are required to confirm this result. The study identified three main nutrient efficient genotypes viz., KBH18, which was the highest yielder, highest in N efficiency and third highest in K efficiency, 8S501-2, which was second highest in yield, highest in K efficiency, third highest in N efficiency and also exhibited early bulking and 15S409, which was the third highest yielder, second highest in N efficiency & K efficiency. The superior genotypes identified in the present study can be subjected to field trials for confirming their superiority and release as a variety.
Open Access
Gene action and gene expression analysis in yardlong bean(Vigna unguiculata ssp. sesquipedalis(L.) Verdcourt) for drought tolerance
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2022) Rahana, S N; KAU; Beena Thomas
Yard long bean (Vigna unguiculata ssp. sesquipedalis (L.) Verdcourt) is a highly remunerative legume vegetable of Kerala. Due to climate change and erratic rainfall, in summer season the crop growth and pod production is heavily affected by moisture stress. Development of high yielding varieties of yard long bean with drought tolerance is essential for its sustainable production. In this context, the present study entitled "Gene action and gene expression analysis in yard long bean (Vigna unguiculata ssp. sesquipedalis (L.) Verdcourt) for drought tolerance" was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, with an objective to identify drought tolerant genotype from the available germplasm and to understand the nature and magnitude of gene action and gene expression involved in the inheritance of drought tolerance in yard long bean. The study comprised four experiments. First experiment dealt with the seedling stage evaluation of 100-yard-long bean genotypes for drought tolerance in field. The moisture stress was imposed by withholding irrigation and later irrigation was restored in order to ensure the survival of the tolerant lines. The results of the analysis showed significant variations among genotypes. Out of the 100 genotypes screened, 15 drought tolerant genotypes were identified based on their better performance in terms of high RLW, low PWP, more number of days for reaching critical stress level and high recovery percentage. The genotypes identified were G1 (Acc 5), G5 (Acc 1339), G6 (Adoor local), G14 (Anchal local II) G15 (Aranmula local), G24 (Elamadu local), G36 (Kattampally local), G42 (Kollam local), G45 (Kottarakara local), G46 (Kottayam local), G50 (Kulashegarapuram local), 051 (Kulathupuzha local), G60 (Muttathukonam local), G74 (Nilamcl local) and G89 (Pongamoodu local). The fifteen selected genotypes from the first experiment were evaluated for drought tolerance in the second experiment by imposing moisture stress at the reproductive stage. Based on the biometric and physiological evaluations, the top seven genotypes with high yield and drought tolerance A4 (Anchal local II), A5 (Aranmula local), A7 (Kattampally local). All (Kulashegarapuram local), A13 (Muttathukonam local), A14 (Nilamel local), and A15 (Pongamoodu local) were selected as parents for further hybridization in experiment in. In the third experiment, LxT crosses were performed by using seven selected tolerant genotypes as lines with three popular yard long bean varieties as testers to generate twenty one hybrids. The genetic analysis of hybrids and parents were evaluated based on eight morphological and eight physiological parameters. Mean performance, combming ability, gene action and heterosis were estimated. Based on the mean performance and gca effects, L4 (Kulashegarapuram local) and L3 (Kattampally local) are identified as outstanding general combiners and can be exploited as parents for drought tolerance breeding in yard long bean. Three superior crosses, Kattampally local x Vellayani Jyothika (L3 x T3), Nilamel local X Lola (L6 X T2) and Kulashegarapuram local x Lola (L4 x T2) were identified as promising combinations for drought tolerance and yield xmder water stress. In the final experiment quantitative real time PCR was conducted to analyze the gene expression of drought responsive genes in tolerant hybrids and parents. The elevated expression of DREBs and NCEDl genes in tolerant hybrids and genotypes in gene expression analysis reflects the increased drought tolerance ability of those genotypes. The gene expression analysis was in conformity with the field studies. All the hybrids mamfested significant amount of dominance variance for commercial exploitation. Existence of significant amoimt of dominance variance and non-additive gene action suggests that hybridization as the best strategy for improving the drought tolerance character in yard long bean. The identified genotypes can be used for isolation of purelines with enhanced drought tolerance and the transgressive segregants from the identified crosses can be used for the development of drought tolerant high yielding cultivars in the fixture. The work can be continued with the identified genotypes and crosses for the development of climate smart drought tolerant varieties of yard long bean.
Open Access
Exploration on the links between soil carbon storage and root biomass and elucidation of drivers of carbon stabilization
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2022) Geethu Jacob; KAU; Manorama Thampatti, K C
The study entitled ―Exploration on the links between soil carbon storage and root biomass and elucidation of drivers of carbon stabilization‖ was conducted at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani during November 2019 to September 2021 with the objective to study the links between soil carbon storage and root biomass in soils of different agro ecological units and to identify the key drivers of C stabilization and NP fluxes under different management practices. The study area comprised of three Agro ecological units (AEUs) of Southern Kerala viz. Southern and Central Foot Hills (AEU 12), Southern High Hills (AEU 14) and Kumily High Hills (AEU 16). The study was carried out in three parts namely exploration on the links between soil organic C and NP pools with root biomass in soils of different AEUs, assessment of carbon storage under different land use system and identifying the drivers of C stabilization and field experiments to study the effect of management practices on the link between root and shoot biomass C and SOC and NP pools. For the study exploration on the links between soil organic C and NP pools with root biomass in soils of different AEUs, the study area was surveyed and geocoded soil samples from 0-20 cm and 20-60 cm depth were collected using core samplers. The root biomass from the soil samples were separated out and weighed. The soil samples were analyzed for its various physical, chemical and biological properties. For assessment of carbon storage under different land use system and identifying the drivers of C stabilization, the most prominent land use system of each AEU was identified and five samples were collected from each system. The sampling size was one sq.m to a depth of 60 cm. The plants of the same area were uprooted and their shoot and root biomass were recorded. Both the soil and plant samples were collected and analysed for various parameters. The field experiment in split plot design on grain cowpea – fodder maize cropping sequence was laid out with the main plot treatments as m1: conventional tillage, m2: deep tillage (30 cm depth) and m3: no till and sub plot treatments as s1: POP recommendation, s2: soil test based POP, s3: organic nutrient management (TOF-F), s4: POP + AMF, s5: soil test based POP + AMF, s6: TOF-F + AMF and s7: absolute control. After the harvest of grain cowpea, shoot biomass were removed and roots were retained in three replications and in the other three replications total biomass of grain cowpea were added into the soil and left for decomposition. After that fodder maize was raised in the field and the crop and soil samples were collected and analysed for various parameters. The results of the Part I revealed that the physical properties like bulk density (BD) and gravel per cent of all the AEUs showed an increase towards depth while the electrochemical properties showed a decrease. Among the different AEUs, AEU 16 recorded lowest BD (1.22 Mg m-3 ) and gravel per cent (30.53 %) and had a subsoil increase of 12 per cent and 17 per cent for BD and gravel per cent respectively. The different fractions of soil C and N showed a decrease with depth for all AEUs. The soil total organic carbon (TOC-5.94 %) and recalcitrant C (RC-1.64 %) content were highest for AEU 14 with a decrease of 26 per cent and 31 per cent respectively for subsoil. The highest dissolved organic C (DOC-54.63 mg kg -1 ) and labile C (LC- 877.50 mg kg -1 ) content were for AEU 16 with a subsoil decrease of 45 per cent and 27 per cent respectively. AEU 12 recorded lower values for C fractions which may be due to decreased root biomass by 38 per cent and 25 per cent in surface soil and 55 per cent and 70 per cent in subsoil than that of AEU 14 and AEU 16 respectively. The root biomass and soil C fractions were positively and significantly correlated at both sampling depths. The highest correlation coefficients between root biomass and soil C fractions were recorded by DOC (0.976) followed by RC (0.931) and LC (0.975) followed by DOC (0.953) for surface and subsoil respectively. From the regression analysis perfect fit towards linear regression model, expressed as R2 value, was highest for DOC (0.95) and LC (0.94) at sampling depths of 0-20 cm and 20-60 cm respectively. The different fractions of N were highest for AEU 12 and surface soil showed an increase in total nitrogen (TN) by 6 per cent and NH4-N by 20 per cent, NO3 – N by 18 per cent and organic N (ON) by 5 per cent than subsoil. For soil P fractions an increase was observed with depth and AEU 12 recorded highest values for P fractions. Among soil N and P fractions, ON and labile P (LP) were found to be more correlated to root biomass and with higher R2 values at both sampling depths. The MBC (26.89 mg kg -1 ) and DHA (34.94 µg TPF g-1 24 hr-1 ) were highest for AEU 16 and surface soil showed an increase in MBC by 28 per cent and DHA by 30 per cent, than subsoil. For part II, the most prominent land use system of each AEU were identified as rubber plantations for AEU 12 and AEU 14 and cardamom plantations for AEU 16. The rubber plantations of AEU 14 recorded highest C storage (434.0 t ha-1 ) and lowest value was observed for cardamom plantations of AEU 16 (329.9 t ha-1 ). The soil physical properties and electrochemical properties behaved similar to that of Part I. Cardamom plantations of AEU 16 recorded lowest BD (0.97 Mg m-3 ) and gravel content (28 %) while AEU 12 had highest pH (5.61) and lowest EC (0.39 dS m-1 ). Among the different land use systems, rubber plantations of AEU 14 recorded highest values for soil TOC (6.72 %) and DOC (55.16 mg kg-1 ) content while cardamom plantations had highest soil LC (910.91 mg kg-1 ) and surface soil RC (1.92 %) content but subsoil RC content was more for rubber plantations of AEU 14. In rubber plantations the root biomass were correlated to all C fractions and more correlated to RC and TOC and in cardamom plantations root biomass were significantly correlated to TOC (0.98) and DOC (0.95) fractions only. A significant and positive correlation between root lignin and soil C fractions (RC and TOC) was also observed. The different fractions of N and P were highest for cardamom plantations of AEU 16 and surface soil showed an increase in TN by 5 per cent, NH4-N by 14 per cent, NO3– N by 22 per cent and ON by 4 per cent than subsoil and a subsoil increase of TP by 12 per cent, LP by 29 per cent and NLP by 11 per cent were also observed. The shoot biomass were more correlated to soil N and P fractions than root biomass and were more correlated to ON and TN and to TP and NLP among soil N and P fractions respectively. A significant positive correlation between N and P removal and soil NP pools were also obtained. The MBC and DHA were highest for cardamom plantations of AEU 16 and surface soil showed an increase in MBC by 25 per cent and DHA by 23 per cent than subsoil. In the field experiment, among the various nutrient management treatments, soil test based POP + AMF (s5) recorded the highest plant height, shoot biomass and grain yield plant-1 (107.70 g) and TOF-F + AMF (s6) showed highest values for root characteristics and quality parameters for grain cowpea. Similarly for fodder maize grown under both conditions, the treatment soil test based POP + AMF (s5) gave highest shoot biomass, fodder yield and quality parameters while highest root biomass were recorded by the treatment, TOF-F + AMF (s6). Among the tillage levels, the no till treatment (m3) performed best in connection with growth, yield and quality characteristics throughout the cropping period. Tillage and nutrient management had significantly influenced various soil properties. The lowest soil BD and higher WSA per cent and soil pH were reported by the treatment TOF-F + AMF (s6) throughout the cropping sequence. Among tillage levels, deep tillage (m2) remained superior for soil BD and pH and no till treatment (m3) for WSA per cent respectively. The treatment, TOF-F + AMF (s6) remained superior for soil C fractions viz., TOC, LC and RC content, mineralizable N fractions (NH4-N and NO3-N), labile P and MBC content and dehydrogenase activity throughout the cropping sequence. The treatment, soil test based POP +AMF (s5) recorded higher values for NP fractions like TN, ON, TP and non labile P (NLP). Among the tillage levels, the no till treatment (m3) remained superior in connection with soil chemical and biological properties especially towards the end of cropping period. As the cropping sequence advances an improvement in soil physical, chemical and biological properties were observed and this is mainly attributed to the crop residue addition of grain cowpea and more improvement was observed for total residue incorporation than root residue alone addition. The soil C pools were highly linked to root biomass and NP pools to shoot biomass. The root biomass and root lignin were the main drivers of C stabilization. The treatments with AMF remained superior in various soil properties and yield and growth attributes emphasizing the favourable role of AMF in C storage and nutrient cycling in soils. With regard to nutrient management, soil test based POP + AMF recorded the highest yield in cropping sequence while organic nutrition (TOF-F) + AMF contributed more to soil properties indicating the need for further research on nutrient translocation and assimilation under organic nutrition. The no tilled condition with total residue incorporation responded better than root residue alone incorporation, hinting to the fact that more organic matter contributing practices improved the physicochemical and biological conditions of soils favourably.
Open Access
Mealybugs of vegetable ecosystems and tritrophic interactions of brinjal mealybugs
(Department of Agricultural Entomology, College of Agriculture ,Vellayani, 2022) Anitha, N; KAU; Mithra, Mohan
The study on “Mealybugs of vegetable ecosystems and tritrophic interactions of brinjal mealybugs” was conducted at College of Agriculture, Vellayani during 2017 to 2020 with the objectives to identify mealybugs and their natural enemy fauna in solanaceous and cucurbitaceous vegetables, to carry out the molecular characterization of mealy bugs in solanaceous and cucurbitaceous vegetables and to find out the tritrophic interactions of mealybugs infesting brinjal. An investigation on mealybug diversity in solanaceous and cucurbitaceous crops of Kerala revealed a total of six mealybug species viz., Coccidohystrix insolita, Ferrisia virgata, Paracoccus marginatus, Phenacoccus solenopsis, Planococcus citri and Pseudococcus jackbeardsleyi. Besides, four mealybugs viz., Crisicoccus hirsutus, Maconellicoccus hirsutus, Planococcus lilacinus and Rastrococcus iceryoides infesting other vegetable crops were also recorded from Kerala. The study also revealed that the population of mealybug, C. insolita collected from different regions of Kerala exhibited significant morphological variation. The molecular characterization studies proved that the population belongs to C. insolita and the variations may be environmental induced. An exploration of the host range of mealybugs infesting solanaceous and cucurbitaceous vegetables in Kerala revealed a total of 113 plants under 73 genera belonging to 31 families, out of which 14 plants were recorded as new host reports. A rich natural enemy fauna on mealybugs belongs to five orders viz., Coleoptera, Lepidoptera, Diptera, Neuroptera and Hymenoptera were documented from Kerala. Twenty species of mealybug predators from five different families were recorded, among which the predominant family was Coccinellidae with 16 species under six genera. Among the various predators collected, Cacoxenus sp. was recorded for the first time as a predator of P. jackbeardsleyi. Eleven hymenopteran parasitoids belonging to five families were documented from mealybugs, of which the majority belongs to the family Encyrtidae. Four new host-parasitoid associations were also recorded for the first 288 time. The study also identified six hyperparasitoids under the family Encyrtidae, of which two species were recorded as new report which includes Cheiloneurus sp. and Prochilonerus sp. associated with the mealybug P. solenopsis. The ants associated with mealybugs in different agroecosystems were also investigated and a total of 14 species of ants belonging to nine genera under three subfamilies were recorded, of which the most dominant subfamily was Formicinae followed by Myrmicinae and Dolichoderinae. The present study also revealed 15 new ant-mealybug associations for the first time. The molecular characterization of eight mealybug species was carried out that complemented the morphological identification of species. A total of eight nucleotide sequences were submitted to NCBI GenBank and accession numbers were generated. The sequences were also submitted to BOLD and illustrative barcodes were generated. The barcodes of C. insolita, C. hirsutus and P. jackbeardsleyi were generated for the first time. The diversity of endosymbionts of the mealybug C. insolita was carried out for the first time. The study revealed a total of 15 phyla of endosymbionts on C. insolita, of which Proteobacteria was the predominant one. An experiment was conducted at Instructional Farm, Vellayani to identify the tritrophic interaction in brinjal, C. insolita and its natural enemies. The study revealed that out of the ten brinjal cultivars evaluated, the lowest mean population of mealybugs was observed in Pusa Uttam whereas the hybrid cultivar, Udit recorded the highest number of mealybugs. The lowest mean per cent leaf infestation was recorded in Pusa Purple Long which was statistically on par with Pusa Uttam whereas the hybrid cultivar, Udit was severely damaged by the mealybugs. Among the tested cultivars, Pusa Purple Long was recorded under the group resistant whereas Udit and Haritha were included under the highly susceptible group based on the mean per cent leaf infestation caused by C. insolita. The cultivar Haritha attracted the highest number of predators whereas the maximum mean population of spiders were observed in Pusa Purple Long. 289 The correlation analysis on the mean population of mealy bugs with biophysical parameters revealed that trichome density, length width ratio of leaf and number of branches exhibited a significant positive correlation with mean population of mealybugs. Correlation studies on the mean population of natural enemies with biophysical parameters revealed that plant height exhibited a significant negative correlation whereas leaf thickness and number of branches revealed a non-significant negative correlation with the mean population of natural enemies. Among the biochemical parameters of brinjal cultivars, total phenol content exhibited a significant negative correlation with the mean population of mealybugs whereas total chlorophyll content showed a significant positive correlation. The correlation between biochemical parameters of brinjal cultivars with the mean population of natural enemies revealed that total phenol and carotenoid content exhibited a non-significant negative correlation whereas total protein content, reducing sugar and total chlorophyll content showed a nonsignificant positive correlation. The info-chemical mediated interactions in brinjal cultivars, mealybug and its natural enemies were studied using a multi-armed olfactometer and Y-shaped olfactometer assay. The results revealed that the cultivar Udit attracted the highest number of natural enemy Chrysoperla zastrowii sillemi while the cultivar Pusa Uttam attracted the lowest number. The variation in preference shown by the natural enemies may be related to the difference in volatile compounds emanating from the host cultivar. The GC-MS analysis of the synomonal compounds of the cultivar, Udit revealed a total of eleven compounds whereas the cultivar Pusa Uttam was recorded with a total of five compounds. The Y shaped olfactometer studies revealed that C. zastrowi sillemi adults showed more preference towards the synomonal compounds of mealybug infested plants than that of healthy plant synomonal extracts. On comparing the volatile profile of synomones of mealybug infested and healthy plants revealed that the synomonal extracts of the mealybug infested cultivar Udit comprised of 11 compounds whereas healthy plant synomonal extracts contained nine compounds. 290 The relative response of C. zastrowi sillemi towards the kairomonal compounds of C. insolita was evaluated in a Y tube olfactometer and the results revealed that the highest mean number of adult lacewings were attracted to the kairomonal compounds of mealybug compared to control. The kairomonal extracts of the mealybug comprised of seven compounds and the composition of these hydrocarbons may determine the selectivity of natural enemies towards the preferred host. The present study recorded a total of six mealybug species infesting solanaceous and cucurbitaceous vegetables and its host range, natural enemies and associated ants in different agro ecological regions of Kerala. The molecular characterization studies supported the morphological taxonomy and the sequences were submitted to NCBI Genbank and BOLD. The study also elucidated the interactions mediated by plant traits and info-chemicals in brinjal-mealybugnatural enemy tritrophic systems. The study recorded Pusa Purple Long as resistant cultivar and Udit and Haritha as highly susceptible cultivar to C. insolita. The plant traits viz., trichome density, length width ratio of leaf, number of branches, total phenol content and total chlorophyll content exhibited significant correlation with mean population of mealybugs whereas plant height exhibited significant correlation with mean population of natural enemies. The study on info-chemical mediated tritrophic interactions revealed that the concentration and composition of volatile compounds determine the differential selectivity of natural enemies. The volatile compounds identified in this study can also be used as a cue in moderating the behavior of natural enemies in the ecosystems. So a thorough knowledge on the tritrophic relations in the ecosystem will aid in manipulating these interactions to devise a better pest management strategy.
Open Access
Protocol development for gel stabilization and nutraceuticals in aloe vera (L.) Burm. f.
(Department of Plantation Crops and Spices, College of Agriculture, Vellayani, 2021) Maheswari R S Nair; KAU; Sreekala, G S
The investigation entitled “Protocol development for gel stabilization and nutraceuticals in Aloe vera (L.) Burm. f.” was carried out in the Department of Plantation Crops and Spices, College of Agriculture, Vellayani during March 2016 to December 2019. The project envisaged formulation of a low cost stabilization technique for aloe gel using herbal extracts and aromatic oils and development of protocols for the preparation of dried latex and marketable nutraceuticals using aloe gel. The study was carried out as four experiments. The first experiment was to study the keeping quality and natural spoilage flora of fresh gel while the second experiment was for the standardization of curacao aloe (dried latex). The third experiment was on gel stabilization using herbal extracts and essential oils. Preparation of nutraceuticals from the stabilized liquidized aloe gel juice was the final experiment. The keeping quality and natural spoilage flora of fresh gel were assessed by subjecting the liquidized aloe gel juice to storage in glass bottles under ambient condition for seven days. The liqudized aloe gel juice was off white in colour for first three days of extraction with mild vegetative odour and got sedimented with foul smell from fourth day onwards. The liquidized aloe juice could not be stored for more than a day due to increased microbial population from the second day of storage. Preliminary trails conducted by pasteurizing the liquidized aloe gel juice at 65 0C and 15 psi pressure for 13 minutes followed by flash cooling registered no microbial population even after seven days of storage. The latex collected from aloe leaves was subjected to different methods of drying such as boiling followed by cooling, sun drying, shade drying and oven drying. Appearance, colour and aloin content (271.62 mg/ml) of dried latex was significantly higher for shade drying. Liquidized aloe gel juice was pasteurized and added with varying concentrations of three forms (aqueous, tincture, decoction) of herbal extracts and essential oils after adjusting the pH to 3.5 by adding 0.5 per cent of citric acid for gel stabilization. The treated samples were kept for a month and based on microbial population and minimum inhibitory concentration best treatment of each form was selected from preliminary trials for aloe gel stabilization. Gymnema sylvestre aqueous extract (1 ml), tincture (1 ml), decoction (2 ml), Centella asiatica aqueous extract (1 ml), tincture (2 ml), decoction (1 ml), Achyranthes aspera aqueous extract (2 ml), tincture (2 ml), decoction (1.50 ml), Tridax procumbens aqueous extract (2 ml), tincture (2 ml) , decoction (1 ml), Terminalia chebula aqueous extract (1 ml), tincture (1 ml), decoction (1 ml), Punica granatum aqueous extract (1 ml), tincture (2 ml), decoction (1 ml), green tea aqueous extract (2 ml), tincture (1 ml) and decotion (2 ml) and 1 ml each of sacred basil oil, lemon grass oil, cinnamon bark oil, clove oil and cardamom oil were selected and added to pH adjusted , pasteurized and liquidized aloe gel juice (25 ml) for gel stabilization. The gel stabilization was thus done using the selected twenty six treatments in a Completely Randomised Design replicated five times and compared with 0.08 per cent sodium benzoate as control and stored for six months. Appearance, colour and odour of all forms of the herbal extracts reduced on storage while those treatments with aromatic oils showed lesser percentage reduction in these parameters. Total solids, amylase and lipase activity decreased on storage. The amino acid content was the highest for liquidized aloe gel juice added with aqueous, tincture and decoction of Achyranthes aspera (0.08 ppm).Vitamin A and C were highest for treatment with green tea leaf aqueous extract which decreased subsequently on storage. An increase in microbial load was observed for all the treatments with herbal extracts from first month of storage. But addition of 1 ml clove oil resulted in stabilization of liquidized aloe gel juice which could be stored upto five months without microbial contamination or affecting the nutritive and sensory parameters. Nutraceuticals were prepared using stabilized liquidized aloe gel juice containing clove oil blended with lemon juice, orange juice and honey in proportions of 50 : 50, 75 : 25 and 90 : 10 followed by pasteurization, flash cooling and stored for 6 months. Appearance, colour and vitamin C were significantly higher for Lemon juice (50 ml) + Liquidized aloe gel juice (50 ml) + 2 ml clove oil while odour, taste, overall acceptability, pH, TSS, carbohydrates and calories were significantly superior for Honey (50 ml) + Liquidized aloe gel juice (50 ml) + 2 ml clove oil. Growth of microbes could be detected from third month of storage for all the treatments. Aloe health drink with honey in the ratio 50 : 50 added with clove oil were selected as the accepted drink which could be preserved for two months without microbial contamination. The preparation of aloe herbal powder by solar drying, air drying, oven drying or freeze drying resulted in a sticky product which could not be reconstituted with distilled water for quality comparison with fresh gel, thus warranting further investigation. The present study revealed that liquidized aloe gel juice pasteurized and mixed with clove oil (4 per cent) is a low cost stabilization method which can be taken as a base material for the preparation of health drink. The nutraceutical with liquidized and stabilized aloe gel juice mixed with equal proportion of honey and preserved with clove oil is a palatable drink having higher calories which could be stored for two months. The dried aloe latex a byproduct produced by shade drying is superior with high aloin content and can also be used for the development of marketable product.
Open Access
Jackfruit (Artocarpus heterophyllus Lam.) as a potential source of bioactive compounds
(Department of Post Harvest Technology, College of Agriculture, Vellayani, 2022) Viresh; KAU; Mini, C
An investigation on “Jackfruit (Artocarpus heterophyllus Lam.) as a potential source of bioactive compounds” was carried out at Department of Post Harvest Technology, College of Agriculture, Vellayani from 2017-2020 with the objectives to standardize the extraction procedure for maximizing the antioxidant, anti-cancerous and anti-hyperglycemic properties of fruit wastes from varikka and koozha jackfruit types, phytochemical profiling, encapsulation and commercial exploitation of encapsulated extracts for fortification of fruit juice beverages. Experiments were carried out in four parts. Standardization of extraction procedure was carried out in the first part by evaluating the extracts for antioxidant, anti-hyperglycemic and anti-cancerous properties. Both varikka and koozha types were harvested at optimum maturity and were utilized at ripe stage independently. Except bulb, seed and peel without horny portion, all other parts were dried in cabinet (D1) and freeze (D2) driers, pulverized to fine powders and extracts were prepared using solvents viz., methanol at 90 (S1), 80 (S2), 50% (S3) and ethanol at 60 (S4), 80 % (S5) with solid to solvent ratios of 1:30 (R1), 1:40 (R2) and 1:50 (R3). Extract of freeze dried varikka samples using 60 per cent ethanol at 1:50 solid to solvent ratio (D2S4R3) had highest Total flavonoid content (TFC) (15.66 mg QE 100g-1 ), Total phenolic content (TPC) (156.10 mg GAE 100g), DPPH scavenging activity (69.29 per cent inhibition) and α-glucosidase inhibition activity (90.24 per cent). The same extract, D2S4R3 from koozha also exhibited highest TFC (15.88 mg QE 100 g -1 ), TPC (164.63 mg GAE 100g), DPPH scavenging activity (68.64 per cent inhibition) and α-glucosidase inhibition activity (92.28 per cent). Freeze dried varikka samples extracted using 90 per cent methanol at 1:50 solid solvent ratio (D2S1R3) recorded the highest (45.88 mg 100g-1 ) ascorbic acid content and freeze dried koozha samples extracted using 90% methanol at 1:40 solid solvent ratio (D2S1R2) had the highest ascorbic acid content of 47.37 mg 100g-1 . 310 Based on the efficiency and economics, extraction of freeze dried samples using 60% ethanol at 1:40 solid to solvent ratio (D2S4R2), similar samples using 60% ethanol at 1:50 solid to solvent ratio (D2S4R3 ) and cabinet dried samples with 60% ethanol at 1:50 solid to solvent ratio (D1S4R3) were selected as three superior extraction methods . The MTT system which is a simple, reproducible and accurate means of measuring the activity of living cells via mitochondrial dehydrogenases was utilized to assess the anti-cancerous properties of the selected three extracts viz., D2S4R2, D2S4R3 and D1S4R3 on HeLa cell lines with doxorubicin as control. Freeze dried varikka and koozha samples extracted in 60 percent ethanol at 1:50 solid to solvent ratio (D2S4R3) had the lowest IC50 value of 129.30 and 157.60 µg mL-1 respectively whereas the IC50 value for doxorubicin (positive control) was18.85 µg mL-1 . When the three superior extracts were subjected to phytochemical profiling in the second part of the experiment using LCMS/MS (Waters UPLC H class system fitted with TQD MS/MS system) for sugars, organic acids, phenolic acids and flavonoids, they were significantly influenced by extraction methods and jack fruit types. Fifteen sugars, ten organic acids, eighteen phenolic acids and fifteen flavonoids were fractionated and identified from the extracts. Extract of freeze dried sample using 60% ethanol in 1:50 solid to solvent ratio (D2S4R3) had highest sugars, organic acids, phenolic acids and flavonoid content. The major sugars identified were fructose, glucose, mannose, sucrose and sorbitol and; organic acids were citric acid, malic acid, shikimic acid, succinic and hydroxycitric acid; phenolic acids were ferulic acid, p-coumaric acid, caffeic acid, benzoic acid, o - coumaric acid; myricetin, catechin, naringenin, quercetin and epicatechin were the major flavonoids. The three superior extracts selected were encapsulated independently by spray and freeze drying in the third part of the study. Two maltodextrin (MD) levels (10 and 20 dextrose equivalence, DE), three carrier to extract ratio (1:10, 1:15 and 1:20), two inlet- outlet temperature of spray drier (180 - 80º C inlet - 311 outlet and 190 - 90º C inlet - outlet) were the process variables for spray encapsulation, whereas for freeze encapsulation, maltodextrin (MD) levels and carrier ratio were selected as process variables. The extract D2S4R3 from varikka and koozha, spray encapsulated using MD 20 DE at 1:20 carrier to extract ratio (Cr3) at inlet and outlet temperature of 180 and 80º C (T1) recorded highest TPC of 115.47 and 117.92 mg GAE 100 g-1 respectively. Varikka and koozha extracts spray encapsulated using MD 20 DE at 1:10 carrier to extract ratio at 190 - 90ºC inlet - outlet temperature (C2Cr1T2) produced encapsulate with highest per cent recovery (83.77 and 82.09 % respectively). Lowest moisture content of 2.46 and 2.55 per cent were recorded by the extracts spray encapsulated using 10 DE MD at 1:20 carrier to extract ratio at inlet - outlet temperature of 190 - 90º C (C1Cr3T2) from varikka and koozha respectively. Based on the superior physico-chemical properties, spray encapsulate of freeze dried varikka and koozha extracts prepared using 60 per cent ethanol at 1:50 solid to solvent ratio (D2S4R3), using 20 DE maltodextrin at 1:20 carrier to extract ratio with 180 - 80°C inlet - outlet temperature (C2T1Cr3), was selected for Part 4 of the experiment. D2S4R3 extract from varikka and koozha, when freeze encapsulated with MD 20 DE at 1:20 carrier to extract ratio had highest TFC of 11.62 and 11.75 mg QE 100 g-1 respectively. Koozha extract, freeze encapsulated with MD 20 DE at 1:20 carrier to extract ratio had highest TPC of 134.38 mg GAE 100 g-1 DPPH scavenging activity of varikka and koozha extracts were highest when freeze encapsulated with MD 20 DE at 1:20 carrier to extract ratio (per cent inhibition of 71.66 and 77.48 respectively). Ascorbic acid content and per cent recovery of encapsulates were not influenced by levels of MD or carrier to extract ratio. The extracts freeze encapsulated with MD 10 DE at 1:10 carrier to extract ratio had lowest moisture content of 2.22 and 2.51% respectively. Based on the superior physico-chemical properties, freeze encapsulate of the freeze dried varikka and koozha extract prepared with 60 per cent ethanol at 1:50 solid to solvent ratio (D2S4R3), using 20 DE maltodextrin at 1:20 carrier to extract ratio, was selected for part 4 of the experiment. 312 The encapsulated extracts were utilized @ 0.01 to 0.1 per cent for development of fortified mango RTS beverages as per FSSAI standards and compared with commercial fortified beverage in the fourth part of study. Mango RTS beverage enriched with the freeze encapsulate of the extracts @ 0.05 per cent was found to be superior with respect to Total Soluble Solids, total phenolic content, antioxidant activity and total sugar content and these were on par with the beverage enriched with spray encapsulates @ 0.05 per cent and commercial fortified beverages. The highest TPC of 41.05 and 41.12 mg GAE 100 ml-1 were recorded in mango RTS beverage enriched with 0.05 per cent freeze encapsulate of varikka and koozha respectively which were found to be on par with the mango RTS beverage enriched with 0.05 per cent spray encapsulate. The highest scavenging activity (76.29 per cent inhibition) was noticed in RTS beverage enriched with 0.05 per cent freeze encapsulate, followed by the beverage mixed with 0.05 per cent spray encapsulate (73.21%). The lowest scavenging activity (55.19 per cent inhibition) was observed in control sample. From the study, it was proved that the extracts prepared from combined inedible parts of both varikka and koozha jackfruit types are potential source for bioactive compounds. Extraction of freeze dried varikka and koozha types using 60 per cent ethanol at 1:50 solid to solvent ratio was standardized as the best extraction method for retention of phytochemicals, antioxidant activity, antihyperglycemic and anti-cancerous properties. Phytochemical profiling of the superior extracts revealed the presence of 15 sugars, 10 organic acids, 18 phenolic acids and 15 flavonoids. Extracts from varikka and koozha spray encapsulated using 20 DE maltodextrin at 1:20 carrier to extract ratio with 180 - 80°C inlet - outlet temperature and freeze encapsulated by using 20 DE maltodextrin at 1:20 carrier to extract ratio retained maximum phytochemicals and antioxidant properties. These spray and freeze encapsulates could be utilized for fortifying mango RTS beverage @ 50 mg 100 ml-1 without affecting the sensory parameters with an enhanced antioxidant activity of 13-16% compared to commercial fortified mango RTS beverage.
Open Access
Characterization and evaluation of plant growth promoting rhizobacteria from rice soils of Wayanad
(Department of Agricultural Microbiology, College of Agriculture, Vellanikkara, 2021) Wickramasinghe, W R K D W K V; KAU; Girija, D
Plant growth promoting rhizobacteria (PGPR) are a group of bacteria that colonize the plant rhizosphere and enhance the growth and yield of plants. The present investigation entitled “Characterization and evaluation of plant growth promoting rhizobacteria from rice soils of Wayanad” was undertaken at the Department of Agricultural Microbiology” during the year 2018-2020, with the objective of isolation, characterization and evaluation of plant growth promoting rhizobacteria from rice soils of Wayanad and formulation of a consortium to improve the growth and yield of rice. Isolation of rhizobacteria with potential plant growth promoting (PGP) activities was attempted from rice rhizosphere soils collected from ten locations in Wayanad district of Kerala. Selective media were used for the isolation of PGPRs including nitrogen fixers, solubilizers of phosphate, K and Zn and fluorescent pseudomonads. A total of 149 isolates obtained on different media were subjected to preliminary screening for growth on selective media, which yielded 32 N-fixers, 16 phosphate solubilizers, four K solubilizers, six Zn solubilizers and two fluorescent pseudomonads. These isolates were evaluated in vitro for PGP activities (production of IAA, NH3, HCN and siderophore) and antagonistic activities against R. solani and X. oryzae. Twenty promising isolates were selected based on their functional efficiency for further characterization using cultural, morphological, biochemical and molecular methods. Four isolates were found to be Gram-positive rods and sixteen isolates were Gram-negative short rods. Eighteen isolates were identified based 16S rRNA gene sequencing and the sequences of all the eighteen isolates deposited in the GenBank of the NCBI. Phylogenetic analysis using MEGA 7 software showed two major clusters and several sub-clusters. A few of the native isolates stood out distinctly from the available accessions in the database, showing that they are genetically diverse. Based on the efficiency of N fixation, P, K and Zn solubilization and other PGP activities, isolates were ranked. Based on ranking, three N-fixers (Bacillus sp. AkNF3, Pseudomonas sp. PkNF4 and Pseudomonas putida KgNF1), three phosphate solubilizers (Bacillus megaterium PkPS1, Acinetobacter schindleri AkPS4 and Achromobacter sp. AvPS1), two K-solubilizers (Microbacterium sp. MvKS1 and Acinetobacter calcoaceticus MvKS3) and two zinc solubilizers (Achromobacter marplatensis ThZnS2 and Cytobacillus kochii PkZnS3) were selected for consortial formulation. Compatibility of ten promising isolates was tested by cross streaking and dual culture methods. Three PGPR based consortia (Consortium 1, 2 and 3) were formulated, each consisting of 5 native isolates (two N-fixers, one each of phosphate, K and Zn solubilizers). These consortia were evaluated in pot culture experiment, along with KAU commercial formulation (PGPR mix-1), at RARS, Ambalavayal, with rice (variety Valichoori) as the test crop. PGPR application was combined with two levels (50% and 75%) of recommended dosage of inorganic fertilizers (RDF). Population of total bacteria, N fixers, P, K and Zn solubilizers was higher in combined application of biofertilizer with inorganic fertilizers than uninoculated treatments and this was indicative of better colonization of native PGPRs in the rice rhizosphere. Growth and yield parameters indicated that application of PGPR consortium with 75% RDF was statistically on par with PoP (KAU) and 100% RDF. Results suggested that 25% inorganic N, P and K can be replaced by using native PGPR consortium without affecting plant growth, yield, plant nutrient content and soil nutrient content. Considering the above parameters, two best consortia (Consortium 2 and Consortium 3) were selected for further field evaluation. Field evaluation was carried out to assess the efficiency of two selected native PGPR consortia at RARS, Ambalavayal. Five treatments included were, consortium 2 + 75% RDF, consortium 3 + 75% RDF, reference biofertilizer PGPR mix-1 + 75% RDF, 100% RDF and farmer’s practice (farm yard manure 5t ha-1 ). Results suggested that root colonization of total bacteria, N fixers, P, K and Zn solubilizers was higher in all treatments of combined application of biofertilizers with 75% inorganic fertilizer than 100% RDF alone. Growth and yield parameters suggested that combined application of Consortium 2 with 75 % RDF was statistically on par with 100% RDF. Therefore, it can be concluded native PGPR strains in consortium 2 (Bacillus sp. strain AkNF3, Pseudomonas putida strain KgNF1, Bacillus megaterium strain PkPS1, Acinetobacter calcoaceticus strain MvKS3 and Cytobacillus kochii PkZnS3) successfully colonized the rice rhizosphere, increased nutrient availability to the plants and produced higher yield. The results also emphasized on the importance of exploiting native, location specific microorganisms as biofertilizer consortium, rather than a common consortium for the entire State. Native PGPR based consortia 2 reduced the 25% of inorganic fertilizer (N, P and K) without affecting the growth and yield of rice. This would be more cost effective and ecofriendly when compared with the use of chemical fertilizers alone. Further multi-locational field trials are required to validate the results before commercialization of this consortium, as a biofertilizer.

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