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Open Access
Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii(Burgess) (Diptera:Agromyzidae)
(Department of agricultural entomology, College of horticulture, Vellanikkara, 2014) Jyothi Sara, Jacob; KAU; Maicykutty P, Mathew
A study on “Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae)” was carried out at the Department of Agricultural Entomology, College of Horticulture, K.A.U., Vellanikkara during 2011-2013 with the objectives of collection and identification of indigenous natural enemies and to assess the pathogenicity of the entomopathogens to explore the feasibility of utilizing them for its management. Surveys were conducted in the vegetable fields for the collection and identification of natural enemies associated with L. trifolii in three districts, namely, Thrissur, Ernakulam and Kottayam from January to March, 2011. The surveys revealed the occurrence of nine species of hymenopteran parasitoids. The per cent parasitism varied from 10.96 to 58.99 per cent among the crops surveyed. Three species of eulophids, namely, Cirrospilus acadius Narendran, C. brevicorpus Shafee & Rizvi and Aprostocetus sp. as well as the braconid, Toxares sp. are new reports for India. Among the parasitoids, Closterocerus spp. were the dominant group followed by Chrysonotomyia sp. All parasitoids were solitary, larval endoparasitoids except Toxares sp. which was larval-pupal in nature. One species each of small ants (Formicidae) and a dipteran fly (Dolichopodidae) were observed as predators on L. trifolii. In the study, no entomopathogens were observed from L. trifolii. Considering the level of pesticide consumption in vegetable crops that undermine the potential of insect parasitoids and also that no entomopathogens could be observed during the survey, it was decided to evaluate entomopathogenic nematodes (EPNs) as biocontrol agents against L. trifolii. Isolation of EPNs from 72 soil samples from Thrissur, Ernakulam and Kottayam districts yielded four isolates of Steinernema carpocapsae. Bioefficacy studies carried out on these four isolates along with Steinernema bicornutum and Heterorhabditis indica showed that S. carpocapsae Isolate - 1 had the lowest LC 50 , LC 90 and LT values indicating their higher effectiveness against the maggots of the pest. 50 Pot culture study conducted to compare the potential of S. carpocapsae Isolate - 1 with other treatments showed that azadirachtin 1 EC at 0.005% was the most effective causing 84.51 per cent mortality to the maggots of L. trifolii. This was followed by the foliar application of H. indica at 32 infective juveniles (IJs)/ maggot which caused 18.98 per cent mortality. Application of Beauveria bassiana at 1×10 7 spores/ ml was not effective. In the field evaluation, fipronil 5 SC at 0.002% was found to be the most effective treatment for controlling L. trifolii followed by azadirachtin 1 EC at 0.005%. Compatibility of the IJs of the S. carpocapsae Isolate - 1, S. bicornutum and H. indica was studied with ten commonly used insecticides in the laboratory by direct exposure method. Chlorantraniliprole 18.5 SC at 0.005% was found to be the most compatible insecticide with S. carpocapsae isolate - 1 causing only 0.17 per cent mortality to IJs at 72 hours after treatment (HAT). Quinalphos 25 EC at 0.05% and chlorpyriphos20 EC at 0.05% were highly incompatible, causing 96.17 and 92.87 per cent mortality of the nematodes. Dimethoate 30 EC at 0.04% was the most compatible insecticide with S. bicornutum and caused only 0.60 per cent mortality at 72 HAT and was followed by azadirachtin 1 EC at 0.005% with 0.78 per cent mortality to the IJs. Quinalphos 25 EC at 0.05% caused 99.93 per cent mortality at 72 HAT. Heterorhabditis indica was compatible with all insecticides except quinalphos 25 EC at 0.05% which was moderately toxic resulting in 39.6 per cent mortality. The virulence, pathogenicity and multiplication of the survived IJs were not affected by the insecticide treatments. Parasitoids and EPNs were observed as potential candidates for the management of L. trifolii. Hence future studies on the bio-ecology and mass production of dominant parasitoids and standardization of methods to improve the efficacy of EPNs are suggested for the successful control of L. trifolii in polyhouses as well as in the field.
Open Access
Heterosis breeding in sesame (Sesamum indicum L.).
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2011) Gayathri, G; KAU; Dijee, Bastian
The study entitled ‘Heterosis breeding in sesame (Sesamum indicum L.)’ was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara. The objectives of the study were to collect and evaluate different genotypes of sesame for morphological traits and yield attributes, to identify useful parents producing heterotic crosses and developing hybrids in sesame. The study also intended to develop male sterile lines in sesame through interspecific hybridization with Sesamum malabaricum. Sesamum indicum and Sesamum malabaricum accessions were collected from Kerala and Tamil Nadu and evaluated for their morphological traits. Wide range of variation was noticed for characters like plant height, number of days to flowering and seed yield per plant which contributed maximum to genetic divergence. The genotypes studied were grouped into six clusters. High genotypic coefficient of variation (GCV) was recorded for number of capsules per plant, plant height, seed yield per plant and number of branches per plant. High heritability with high genetic advance as per cent of mean was recorded for number of days to flowering, plant height, number of branches per plant, number of capsules per plant and seed yield per plant. This indicates that the characters are governed by additive gene effects and selection for these traits will be effective. Association analysis revealed that seed yield per plant was correlated to plant height, number of capsules per plant and number of days to flowering. Path coefficient analysis indicated maximum positive direct effect by number of capsules per plant, capsule length, plant height and 1000 seed weight on seed yield per plant. In order to develop hybrids, fourteen parents were selected based on the per se performance of the genotypes. They were crossed in line X tester mating design. Forty eight hybrid combinations obtained were raised in the field along with the parents and evaluated for their heterosis and combining ability effects. Parental genotypes AVTS-06-5, AVTS-06-10, IVTS-06-12, KYM-1, Tilak and TMV-6 were identified as high combiners based on general combining ability (gca) effects. Two combinations viz. AVTS-06-5 X KYM-1 and IVTS-06-12 X TMV-3 had significant values of per se performance, specific combining ability (sca) effects and standard heterosis for seed yield per plant. They can be evaluated for their hybrid vigour over locations and seasons. The crosses AVTS-06-5 X TMV-3, AVTS-06-5 X TMV-6 and TCR 3279A X KYM-1 have been identified as potential cross combinations for isolation of promising segregants as the parents involved in these crosses had high significant gca effects for seed yield per plant but the hybrids recorded non significant sca effects. Interspecific hybridization between S.malabaricum and S.indicum was attempted to develop male sterile lines. Seed set was noticed in three interspecific hybrids which failed to germinate due to embryo abortion. Hence these embryos were rescued and raised in vitro to obtain the hybrids.
Open Access
Development of F1 hybrids of indeterminate tomato (Solanum lycopersicum L.) for protected cultivation
(Department of Olericulture, College of Agriculture, Vellayani, 2015) Lekshmi, S L; KAU; Celine, V A
The present investigation entitled “Development of F1 hybrids of indeterminate tomato (Solanum lycopersicum L.) for protected cultivation” was conducted at the Department of Olericulture, College of Agriculture, Vellayani, from 2013 to 2015 with the objectives of identifying superior varieties and developing F1 hybrids of indeterminate tomato suited for protected cultivation. The study consisted of two experiments conducted in the naturally ventilated polyhouse of size 50 m x 20 m located at the Instructional Farm, Vellayani. In the first part of the first experiment, 40 tomato genotypes were evaluated for two consecutive years in an RBD with three replications. As the second part, 12 commercial hybrids were evaluated. The second experiment consisted of a 9 x 9 half diallel analysis laid out in an RBD with three replications. Analysis of variance showed significant differences between the genotypes for all the characters for two crops. Pooled analysis revealed that, LE 1 recorded the highest yield (2443.43 g) and fruit weight (108.13 g) followed by LE 7. LE 53 had maximum number of fruits per plant (65.00). In the present study, genotypes had wide variation for quality parameters. Fruits of LE 14 recorded highest TSS with a mean of 5.74 ºBrix. LE 7 had maximum ascorbic acid (30.13 mg/100g) and lycopene content (13.09 mg/100g). Beta carotene value was maximum in LE 16 (184.15 mg/100g). There was minimum incidence of pests, diseases and physiological disorders under protected conditions. Among the 12 hybrids evaluated, INDAM 9802 was the highest yielder (1444.40 g) followed by F1 T 30 (1412.22 g). F1 T 30 recorded maximum fruits per plant (35.66) which was on par with F1 Queen (35.55). Genetic parameters like phenotypic and genotypic coefficients of variation, heritability and genetic advance were studied to assess the genetic variability among the genotypes. High heritability coupled with high genetic advance were observed for characters like truss per plant, fruits per truss, fruit weight, fruits per plant, yield per plant and yield per plot. Path analysis revealed highest positive direct effect for fruit weight (0.3956), truss per plant (0.3558) and fruits per plant (0.3381). Based on D2 analysis the 40 genotypes were grouped into eight clusters. Cluster I was the largest with twenty four genotypes followed by cluster II with ten genotypes. Diallel analysis was carried out using nine parents selected based on genetic divergence and per se performance. The parents were crossed in a diallel fashion excluding reciprocals to obtain 36 F1 hybrids. The study revealed that P5 x P9 had the highest yield (3114.03 g) which was on par with P6 x P8 (3074.37 g) and P1 x P5 (3077.58 g). P1 x P5 had the maximum fruits per plant (103.93). The magnitude of relative heterosis, heterobeltiosis and standard heterosis varied considerably. For yield, relative heterosis ranged from -32.40 to 92.72, heterobeltiosis from -47.14 to 89.54 and standard heterosis from 2.91 to 160.95. The σ2gca and σ2sca ratio indicated that non-additive gene action was predominant for all traits. Among the nine parents, P9 (LE 1), P5 (LE 20) P1 (LE 2), and P2 (LE 7) were superior for yield and yield attributes. The estimates of sca effects indicated that P5 x P9 (LE 20 x LE 1), P6 x P8 (LE 39 x LE 38) and P1 x P5 (LE 2 x LE 20) were the most promising hybrids for protected cultivation. The present study revealed that the genotypes LE 1 and LE 7 and the hybrids INDAM 9802 and F1 T 30 were superior for yield and yield attributes under protection. Based on the mean performance, standard heterosis and sca effects the three potential crosses viz., P5 x P9, P6 x P8 and P1 x P5 could be adjudged as suitable indeterminate tomato hybrids for protected cultivation.
Open Access
Economic valuation of mangrove ecosystems in Kerala
(Department of Agricultural Economics, College of Horticulture, Vellanikkara, 2013) Hema, M; KAU; Indira Devi, P.
Mangroves are invaluable treasure o f our biodiversity with immense ecological and economic significance. But mangroves wealth of the world is depleting at an annual rate of -0. 34 per cent. Mangroves in Kerala, constitute 0.3 per cent o f that in India, is reported to be high in species diversity. The available reports indicate the depleting status o f the ecosystem in Kerala too. The socio-economic and ecological significance o f this ecosystem is to be studied in detail for assisting policy decisions when confronted with the conservation-development debate. This study was undertaken in this background. The study identified the stakeholders o f mangrove ecosystems o f Kerala and quantified the level o f dependence o f local communities for their livelihood and estimated the aggregate demand for products and services. Further, it identified and quantified the relative influence o f socioeconomic, institutional, climatic and anthropogenic forces on the destruction of mangroves and finally assessed the Total Economic Value (TEV) o f mangrove system and suggested policy prescriptions for the conservation and management of mangroves in Kerala. The study was conducted in the mangrove areas o f Emakulam and Kannur districts of Kerala. These two districts accounted for nearly 65 per cent o f the mangroves o f the state. The study was based on primary and secondary data. The primary data was gathered from 480 respondents belonging to four identified stakeholder groups (residents, fishermen, paddy farmers and general public), selected through simple random sampling method. Data was collected through personal interview using structured pretested interview schedule along with direct observation. The major tools of data analysis were Contingent Valuation Method (CVM) and Choice experiment. The data collection was conducted during June 2012 to January 2013. I Four stakeholder groups o f the mangrove ecosystem in the study area were residents living close to mangroves (<1 km from mangroves), fishermen (inland fishermen and women, engaged in shell mining and clam collection, shrimp farmers), paddy farmers (Pokkali and Kaippad) and general public (resides away from the mangroves). The residents were depending on the mangroves for extraction o f fuel wood, fodder and poles. On an average the level o f extraction was 307 kg o f fuel wood, 1024 kg of fodder and 14(no.) o f poles per year valued at X 4628/household. This amounted to 3 per cent o f their annual household income. The major species o f fish catch by the fishermen were Etroplus, shrimp, crab and Tilapia which was quantified at 1553 kg/ year valued at X 1,41,045. Shell mining which was found to be a major economic activity in Kannur region could generate an income of X 30,000/annum through the extraction and sale o f 7500 kg o f shells. Clam collected was quantified at 225 kg/year valued at X 5625. Thus, the average gross income from these activities was estimated at X 1,77,164 per year which was the main source o f income for the household. About 8 per cent of the fishermen were involved in shrimp farming and were mainly from Kannur district. The size o f the farm varied from 0.4 to 2 ha. The input cost/ha was X 2.8 lakhs which includes cost o f seed, feed, lime and water management. Labour cost was estimated at X 77,000. Hence total cost and returns o f shrimp farming/ha was X 3.27 and 4.75 lakhs respectively with net income o f ? 1.48 lakhs. Pokkali and Kaippad agricultural systems are proved to be closely interconnected with the:.mangrove ecosystem and the per hectare gross returns was X 60,007 and X 40,935 respectively. This amounted to average 30 per cent o f their household income. The respondents’ perception on the pattern of change and the major factors that effected the change in mangrove ecosystem was studied based on their responses. 46 per cent o f the respondents were o f the opinion that the mangrove ecosystem has declined over years and facing threat. The major factors responsible for the same were reported as anthropogenic, climatic forces and status o f property rights. The 11 developmental interventions like LNG Petronet Terminal, Puthuvypeen and ICTT Vallarpadam has resulted in large scale conversion o f mangrove areas. The contradictory forces o f development and conservation led to destruction of mangrove ecosystem. One fifth respondents opined that climatic factors were responsible for the decline. Nearly 85 per cent of the mangroves in the state were reported to be under private ownership and rest under public. The property right status along with economic status influences the rate o f depletion. The legal interventions and community and institutional efforts also influence the status of mangroves, most often positively. The economic valuation of ecological benefits o f mangroves was attempted employing the Contingent Valuation Method. The respondents expressed their willingness to contribute towards conservation both in cash and kind (cash payment and manual participation as labour and as volunteer in awareness programmes) and in combination. The average WTP expressed by the respondents was f 2308/annum the range being ? 50-28,870. The TEV of the mangrove ecosystem of the state was thus ? 1,17,947 million, which was 0.14 per cent ofthe GSDP (2011-12). A socially preferred management plan was identified among a set of alternatives, employing the choice experiment method. Among the management options given, the stakeholders preferred community management (41.6%) followed by public management (29.2%) and status quo (21.4%). The community management of the mangrove ecosystem provides opportunity for the local community to participate in management decision process. At the same time, the importance o f public funding for such activities is revealed in the analysis. The study suggests initiating scientific attempts on realistic area estimation and mapping o f the mangrove resources in the state. There should be attempts to identify and classify the species and document the traditional wisdom associated with them. Region specific studies are needed to establish and quantify the extent of association between mangrove ecosystem and the livelihood activities of local communities. The TEV justifies the increased resources allocation for the conservation efforts. Further, the implementation of community management system as institutional form for mangrove management in the state is suggested.
Open Access
Incorporation of tomato leaf curl virus (Tolcv) resistance in bacterial wilt resistant tomato.
(Department of Olericulture, College of Horticulture, Vellanikkara, 2011) Koteswararao, Yadav; KAU; Sadhankumar, P G
Investigations on “Incorporation of Tomato Leaf Curl Virus (ToLCV) resistance in bacterial wilt resistant tomato” were undertaken in the Department of Olericulture, College of Horticulture, Vellanikkara during the period from January, 2009 to May, 2011. Eighty tomato genotypes collected from India and abroad were screened for ToLCV resistance of which 26 were found to be highly resistant under natural screening. Of these, 20 genotypes (LE-474, LE-635, LE-640, LE-658, LE-666, LE-667, Arka Ananya, IIHR-2195, IIHR-2196, IIHR-2197, IIHR-2198, IIHR-2202, IIHR-2747, TLBRH-1, TLBRH-6, Cherry Tomato, H-24, H-86, Hawaii-7998 and Rani) were highly resistant to ToLCV under both graft transmission and whitefly transmission there by confirming their resistance to ToLCV. Seventy six tomato genotypes were screened for bacterial wilt resistance in bacterial wilt sick plot. Spot planting with known suscept Pusa Ruby was done to confirm the presence of virulent bacteria in the field. Anagha, Sakthi, Mukthi, LE-1-2, LE-626 and LE-474 were resistant to bacterial wilt. Three additional sources of resistance were identified viz., LE-628, LE-640 and LE-649. Five bacterial wilt resistant genotypes (Anagha, Sakthi, Mukthi, LE-1-2 and LE-626) were crossed with seven ToLCV resistant genotypes (IIHR-2195, IIHR-2196, H-24, H-86, Hawaii-7998, LE-474 and LE-640) in a line x tester fashion. Thirty five F1 hybrids developed were screened for both ToLCV and bacterial wilt resistance. Thirty hybrids were highly resistant to tomato leaf curl virus (ToLCV) among the 35 hybrids. Sixteen F1 hybrids were resistant to bacterial wilt. There were 15 F1 hybrids which were resistant to both ToLCV and bacterial wilt. Line x tester analysis was performed to derive information on general combining ability and specific combining ability effects, gene action and heterosis. Good general combiners for different characters were identified. Among the F1 hybrids Anagha x LE-640 was the earliest to flower and earliest to harvest. Sakthi x LE-640 (1.4 kg/plant) gave the maximum yield among the hybrids and parents followed by Mukthi x H-86 (1.1 kg/plant) and LE-1-2 x Hawaii-7998 (1.06 kg/plant). Maximum number of fruits were produced by LE-1-2 x Hawaii-7998 (39.67 fruits/plant). The maximum sized fruits were produced by Anagha x IIHR-2195 (55.93 g) followed by Sakthi x LE-640 (55.78 g) and Sakthi x IIHR-2196 (55.09 g). F2 segregants of 35 crosses were screened for combined resistance to bacterial wilt and ToLCV. Thirty F2 segregants were resistant to both bacterial wilt and ToLCV. Mukthi x IIHR-2195-F2-47 (1.7 kg/plant) and Mukthi x IIHR-2195- F2-34 (1.5 kg/plant) were the highest yielders among the 30 segregants. Segregation pattern in F1, F2, B1 and B2 of the cross combination Pusa Ruby x IIHR-2195 revealed that the resistance to ToLCV in IIHR-2195 is controlled by a single dominant gene.
Open Access
Environmental concerns in the development projects on rice farming under decentralized planning
(Department Of Agricultural Extension, College Of Agriculture, Vellayani, 2011) Smitha, K P; KAU; Anilkumar, A
The study entitled ‘Environmental concerns in the development projects on rice farming under decentralized planning’ was undertaken with the major objective of studying the nature and extent of environmental concerns in planning and implementation of development projects on rice farming under decentralized planning in Palakkad District. Environmental awareness and constraints perceived by stakeholders in planning and implementation of the projects were also studied. The research project was undertaken in Palakkad district, as the district accounts for about 1/3rd of the total area under rice cultivation of Kerala state. Four blocks, viz. Kollengode, Kuzhalmannam, Chittur and Alathur were selected purposively based on the highest area under rice. Thekkinchira, Nelliancaud, Manchira and Kolapadam padashekarams were randomly selected from the above four respective blocks. Ten each of beneficiary farmers, agricultural labourers, people’s representatives/social activists in the same padashekaram were selected randomly for the study. Thus a total of 40 beneficiary farmers, 40 agricultural labourers and 40 people’s representatives/social activists were selected from the study area. In addition to those included in the selected projects / padashekarams, extension functionaries from other regions of the district were also randomly selected, so as to make a sample size of 40. Thus a total of 160 respondents belonging to the four categories constituted the sample of this study. The data collected were statistically analyzed using arithmetic mean, percentage, canonical correlation analysis and principal component analysis. The study on environmental concerns and awareness of stakeholders revealed that the farmer respondents had high to medium level of environmental concerns and awareness. Most of the agricultural labourers possessed medium level of environmental concerns while all of them were in the medium awareness category. All the extension personnel and majority of people’s representatives/social activists had high awareness and concern for environment. In the nature of environmental concerns it was found that in the land and soil management dimension, most of the padashekarasamithi considered three technologies while planning viz. (1) practicing crop rotation with pulses/leguminous green manures /fringe cropping with cowpea (2) application of nitrogen and potassium in two to three split doses and (3) application of lime while all the farmer respondents adopted two technologies viz. (1) applying nitrogen and potassium in 2-3 split doses according to the duration of the variety and (2) incorporation of crop residue in the field. While majority of the samithis considered only a single water management technology in the planning stage (selection of suitable varieties based on water availability) all the respondents adopted three major water management practices viz.(1) summer ploughing, (2) land/leveling/ puddling and (3) maintaining standing water as per crop requirement. All the samithis included augmentation of parasite / predator population in the field / use of natural enemies like Pseudomonas in the planning stage. Majority of the farmers avoided poaching and killing of birds and animals in rice fields. Selection of right season was considered in the planning stage by all the samithis and all the respondent farmers ploughed the field and exposed it to sun as a part of the plant protection practices. With respect to the extent of environmental concerns in the planning stage, majority of the farmers were found to be in the lower class of adoption with regard to land and soil management, water management, biodiversity conservation and plant protection practices while most of them were in the medium category in the implementation stage of all the four dimensions. Percentage adoption of land and soil management practices, water management, biodiversity conservation and plant protection practices was very high over planning and it was the highest in case of water management dimension. The above results show the inefficient planning at padashekarasamithi level and a better adoption and environmental concerns at the farmer level. Analysis of the relationship between the dependent variables (environmental concerns, awareness and extent of environmental concerns reflected in adoption of eco-friendly technologies) and profile characteristics of farmers revealed that environmental concern is the most important dependant variable and the profile characteristics viz. perception on the importance of mitigating environmental degradation, indigenous wisdom orientation, knowledge on eco-friendly rice cultivation, experience in eco-friendly farming, sense of empowerment, risk orientation, export orientation, educational status and participation in environment related activities contributes the most in developing environmental concerns and awareness. In the case of all other respondents out of the two dependent variables viz. environmental concerns and awareness, environmental concern is the most important dependent variable than environmental awareness. The variables sense of empowerment, experience in eco-friendly farming, knowledge on eco-friendly rice cultivation, perception on the importance of mitigating environmental degradation, age and indigenous wisdom orientation play crucial role in developing concern and awareness on environment in agricultural labourers while communication effectiveness, decision making ability and participation in environmental activities have the highest influence on the dependent variables in the case of extension personnel. Perception on the importance of mitigating environmental degradation, educational status, indigenous wisdom orientation, leadership, attitude towards group management and participation in environmental activities play very important role in defining environmental concern and awareness of people’s representatives / social activists. The B-C ratio of eco-friendly rice cultivation, conventional rice cultivation and cow based minimum budget rice farming (Gō-adharitha krishi) was 1.39, 1.79 and 2.2 respectively. The major reason for this is the higher cost of cultivation incurred in the case of eco-friendly rice cultivation which is due to the high cost of organic inputs and its application. But the price in the market is the same irrespective of the methods of production, which reduce the profit for eco-friendly farmers. Cow based minimum budget rice farming (Gō-adharitha krishi) portrays the success of eco-friendly farming by way of value addition and better marketing. The mean social benefit-cost ratio for all the respondents was high, which substantiates the general perception that social benefits derived from eco-friendly rice farming was higher than the social costs. The dimensions such as non- remunerative price, higher cost of cultivation and inconvenience in handling eco-friendly inputs contributed higher magnitude of variation towards social cost and the dimensions, superior quality of rice, enrichment of biodiversity, improvement in water quality and self-development contributed to higher magnitude of variations towards social benefit. Most of the farmers considered padashekarasamithi as a supplier of inputs from krishi bhavans, which was a major constraint in the planning stage while in the implementation stage the major constraint perceived by them was the labour unavailability. The labourers professed labour unavailability, lack of knowledge on eco-friendly techniques, lack of good quality, certified organic inputs in the market and higher cost of these inputs as the major constraints in the implementation stage. The major constraints according to the extension personnel were lack of co-ordination among the members of padashekarasamithi in the planning stage and labour unavailability, lack of good quality, certified organic inputs in the market in the implementation stage. While in the case of people’s representatives/social activists the major constraint perceived in the planning stage was the farmers outlook of padashekarasamithi as a mere input supplier of krishi bhavan. This group of stakeholders felt labour unavailability and problems in marketing organic rice due to its difficulty in getting it certified as the major constraints in the implementation stage. Some of the important policy prescriptions in the light of the study which the government should undertake are (i) offer incentive price for rice produced in an eco-friendly way (ii) provide assured market and farmer-customer networking (iii) simplify procedures of organic certification (iv) develop certification procedures for eco-friendly rice (v) value addition and (vi) offer incentives for farmers practicing clean agriculture (vii) encourage and conscientize farmers for cultivation of traditional varieties and use of indigenous wisdom (viii) redefining and updating organic farming policy (ix) encourge group approach in organic rice farming (x) encourage mixed farming (xi) maintain biodiversity register for grama panchayats and (xii) ensure availability of eco-friendly inputs .
Open Access
Integrated culture of fish with micropropagated plants in a recirculatory system
(Department of Aquaculture, College of Fisheries,Panangad, 2012) Navya, R; KAU; Devika Pillai
An experiment was designed to study an integrated recirculatory sytem with micropropagated aquarium plants, fish and indigenous filter materials like coir, vetiver and bamboo as the filter media. The plants selected for the study were Bacopa caroliniana, Anubias minima, Aponogeton ulvaceus, Rotala rotundifolia and Nymphoides cristata. The first part of the work was to standardise the micropropagation techniques for the above said plants. Murashige and Skoog medium (half and full strength) was used as the basal medium for the establishment of cultures. The explants varied from nodal segments, rhizome buds, leaf petioles and lateral buds. Surface sterilization was carried out with a range of sterilants like mercuric chloride solution, ethyl alcohol, sodium hypochlorite solution etc. for varying durations and concentrations depending on the type of explant. Effect of growth regulators on explants were studied using auxin IAA and cytokinins, BA and Kn. A liquid culture media with 1.5mg l-1 BA and 0.1mg l-1 Kn concentrations was the best medium for Bacopa caroliniana. A combination of auxin cytokinin like 1.5 mg l-1 BA and 1.0 mg l-1 IAA in liquid culture was the best medium for Rotala rotundifolia. In Nymphoides cristata, hormone concentration of 1.0 mg l-1 each of BA and IAA in liquid culture gave the best results. In Anubias minima, a full MS solid medium with 6.0 mg l-1 of BA gave better results compared to lower levels of BA. In vitro trials for Aponogeton ulvaceus was not successful due to the exudation of phenolic extracts in all the treatments which eventually lead to the death of the tissues. Hardening success was 90 percent, 100 percent, 70 percent, 100 percent in the case of Anubias minima, Nymphoides cristata, Rotala rotundifolia and Bacopa caroliniana respectively. The micropropagated plants were incorporated in the recirculatory system along with fish and three different biofilter materials like coir, vetiver and bamboo splits. The study focused mainly on the filtering efficiency of the three filters based on the nitrification curves. The plants were included in the system to be a part of biofilter and their exclusive role in nitrification was not studied since this is a preliminary work. A nitification graph was plotted with the observed values of ammonia, nitrite and nitrate in the three different biofilter systems and compared with a control. It was inferred that coir fibres were the best of filter materials tried in nitrification followed by bamboo and vetiver. The control system took more time (45 days) in stabilizing ammonia levels due to lack of a substratum for growing nitrifying bacteria.
Open Access
Biochemical and molecular studies on post-harvest physiological deterioration of cassava (Manihot esculenta crantz)
(Department of plant physiology, College of agriculture,Vellayani, 2015) Saravanan, R; KAU; Roy Stephen
The project entitled “Biochemical and molecular studies on post-harvest physiological deterioration of cassava (Manihot esculenta Crantz)” was conducted at the Dept of Plant Physiology, College of Agriculture, Vellayani and at ICAR-CTCRI, Thiruvananthapuram during 2013 to 2015. The main objective of the work was to analyse the physiological biochemical and molecular mechanisms associated with post harvest physiological deterioration (PPD) and develop methods to delay the PPD in cassava. The initial screening of the cassava genotypes for their performance of PPD was done with 61 different genotypes including some released varieties. Significant differences were observed for PPD development and shelf-life of harvested roots. Cassava genotypes such as IMS2-8, 9S-172, 11S-53, IRS 2-10 and 9S-286 started showing the visible discolouration in the parenchyma tissue earlier (less than 3 days of storage). Genotypes such as 9S-7, 9S-98, 11S-31, 11S-86, 11S-14, CE63-3, CI43-2, CR43-2, CR54-A5, CR59-8R, Sree Athulya and Kalpaka showed low PPD scores and better shelf-life. Tissue imprinting for peroxidase enzyme showed that there was a remarkable increase in peroxidase activity in the root tissues with increasing PPD symptoms. There was no correlation between the root morphological traits and PPD severity. Carotene and starch content of root did not influence the PPD in the genotypes studied. Chemotypic profile of roots with PPD symptoms was used to classify the genotypes based on PPD. To develop an objective screening tool, Near Infrared Spectroscopy (NIRS) was utilized to analyse root samples for PPD. Principal component analysis (PCA) and chemometric tools clearly grouped the different PPD category in root tissues. Various stains such as saffranin, aniline blue, erythrocin, fast green and phloroglucinol stained the tissue specifically at vascular tissues and other cell components and were not suitable for detecting PPD. Storage techniques such as storing the harvested roots in de-aerated bags, wax coating and burying the roots under the soil were employed with selected cassava varieties like Sree Athulya, Sree Jaya, Vellayani Hrashwa, Kalpaka and Sree Padmanabha to delay PPD. Wax coating was suitable to reduce PPD for few weeks. Effect of different storage temperature on PPD was studied for five cassava varieties. Root respiratory flux was higher in roots stored at ambient conditions compared to high (40o C) or low temperature (4o C) storage. There were significant positive correlation between root respiratory flux at 3 and 9 days of storage to the CAT and POX activities studied in different cassava varieties. Roots were treated with various food preservatives at two different concentrations (0.5 and 1%). There was a weak, but significant reduction in symptom development in butylated hydroxy touline – (BHT, at 0.5 and 1% level) treated roots compared to other treatments. Nearly three folds increase in total phenol content was noticed in BHT and butylated hydroxy anisole (BHA) treated roots. The plant hormones related to wound response such as Salicylic acid and jasmonic acid were used to study the PPD response in roots under storage. The roots did not show marked influence to hormone application. Significant genetic variation was observed for PPD. The low PPD type genotypes such as 9S-7, 9S-98, 11S-31, 11S-86, 11S-14, CE63-3, CI43-2, CR43-2, CR54-A5, Sree Athulya and Kalpaka can be utilized for breeding programmes. High temperature storage of cassava at 40 oC resulted in reduced respiratory rate and increased antioxidant scavenging enzyme activity and also reduced the PPD. Differentiation of cassava roots at the metabolites level corresponding to visual symptoms and chemotypic profile of PPD and NIR spectroscopy offer a rapid screening tools. Among the different storage treatments, wax coating with antiseptic pre-treatment is most suitable and economical for increasing shelf-life of roots. Food preservatives like BHT and BHA have a significant, albeit marginal influence on PPD symptom development in cassava.
Open Access
Bio-ecology and management of papaya mealybug on mulberry
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2014) Rajan, V P; KAU; Krishnakumar, R
The experiment entitled “Bio-ecology and management of papaya mealybug on mulberry” was carried out at College of Agriculture, Vellayani, Kerala Agricultural University and in farmers’ fields at Agali, Sholayur and Puthur panchayats during October 2009 to July 2012. The main objectives of the study were to identify and assess the extent of infestation of papaya mealybug on mulberry, its role in disease transmission and population dynamics and to evolve an Integrated Pest Management (IPM) strategy to contain the pest. Preliminary survey conducted in sericulture practising districts of Kerala revealed heavy infestation of the pest in three panchayats of Palakkad district in Kerala. The mealybugs identified in the survey were papaya mealybug, Paracoccus marginatus Williams and Granara de Willink, pink hibiscus mealybug, Maconellicoccus hirsutus (Green) and breadfruit mealybug, Icerya aegyptiaca (Douglas). The occurrence of papaya mealybug and its egg masses were found to be high during the period of May to August. The competition between these three mealybugs and also the influence of weather parameters on the population of the papaya mealybug was studied. The mealybug population showed positive correlation with maximum temperature, sunshine and wind speed and negative correlation with minimum temperature, rainfall and humidity. The different plants belonging to families Asteraceae, Euphorbiaceae, Malvaceae and Solanaceae were observed to be the most preferred hosts for papaya mealybug. The highest number of all life stages of papaya mealybug was observed on Parthenium, Parthenium hysterophorus L., which augmented the perpetuation of papaya mealybug in the absence of other crop hosts. Sprouted potatoes were the host material used for studying the biology of the papaya mealybug, pink hibiscus mealybug and breadfruit mealybug. The average number of eggs laid by an adult papaya, pink hibiscus and breadfruit mealybug were 361.50, 281.30 and 141.30 respectively. The mean larval period of papaya, pink hibiscus and bread fruit mealybugs were found to be 16.7, 21.2 and 47.1 days respectively. DAC-ELISA was performed with infected mulberry plants using antibodies of SCBMV and BSV showed the absence of virus in the infected samples collected from the mealybug infested mulberry gardens. The phenol content was also assessed in the infested samples to get an indication of the level of resistance showed by the host plant against mealybug. The level of resistance of the plant found to be increasing with the increase in the per cent damage. The fifth instar larvae of the predator, Spalgis epius was found as the most active feeder with a feeding potential of 21.69, 118.88, 40.88 and 20.49 of ovisacs and first, second and third instars of papaya mealybug respectively. Third instar larvae of green lacewing, Chrysoperla carnea (Stephens) and fourth instar grubs of ladybird predator, Cryptolaemus montrouzieri (Mulsant) were the most voracious feeders and they consumed significantly higher number of ovisacs, first, second and third instar nymphs of papaya mealybug as compared with first and second instar larvae of the predators. Among the different insecticides evaluated in the laboratory against the first instar and adult papaya mealybugs, dimethoate 0.1% was superior followed by imidacloprid 0.01%. Among the combinations, dimethoate 0.05% + econeem plus 2 ml L-1 was found to be superior with the highest per cent mortality of 93.33% and 96.67% for adult and first instar papaya mealybugs respectively. The silkworm larvae fed with the leaves after 15 days of treatment with the combination of dimethoate 0.05% + econeem plus 2 ml L-1 gave the highest yield of (91 /100 larva reared) cocoons with a total larval duration of 576 hours. Single cocoon weight was found to be high (1.56 g) with the highest shell ratio (22.09). The mean larval weight of different instars were 0.54, 0.87, 1.16, 8.80 and 36.61 gram respectively in first, second, third, fourth and fifth. In the above treatment, effective rearing rate (ERR) by number and weight were 9050.00 and 13744.69 g respectively. Field evaluation with the combination of pruning and weeding along with application of dimethoate (0.05%) 1.7 ml + econeem plus 2 ml L-1 and also providing a second spraying with dichlorvos (0.05%) 2 ml + econeem plus 2 ml L-1 was observed to be superior among all the treatments with minimum leaf damage, shoot damage and highest leaf yield per plant. B: C ratio worked out also confirmed the superiority of this treatment. Hence this treatment can be recommended as an IPM strategy for the management of papaya mealybug on mulberry.

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