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Open Access
Antioxidant and anticarcinogenic potential of jackfruit based ready-to-cook (RTC) curry mixes
(Department of Community Science, College of Agriculture,Vellayani, 2019) Gayathri Mohan; KAU; Suma Divakar
The research work entitled, “Antioxidant and anti-carcinogenic potential of jackfruit based Ready-To-Cook (RTC) curry mixes” was conducted at College of Agriculture, Vellayani during 2017-2019, with the objective to ascertain the antioxidant and anti-carcinogenic properties of the jackfruit based curry mixes (‘Avial’ mix, ‘Koottu’ mix and ‘Ularth’ mix) which were developed earlier at the Department of Community Science, using raw jackfruit (Koozha type). Methanol, ethanol, petroleum ether and acetone were used to extract the bioactive compounds of the powdered mixes for phytochemical screening, antioxidant analysis and verification of anti-carcinogenic property. The results of the phytochemical analysis indicated the presence of tannins, flavonoids, saponins, steroids, phenolic compounds, cardiac glycosides and anthraquinones in the three mixes; whereas the analyses revealed the absence of alkaloids and phlotobatinins. Quantitative analysis of antioxidants revealed that the beta carotene content of the RTC mixes was in the range of 0.07-1.16 mg/100g. Beta carotene content was found to be more in ‘Avial’ mix (1.16mg/100g). Ascorbic acid content was also found to be higher for ‘Avial’ mix (38.45 mg) and the lowest content was found for ‘Ularth’ mix (15.34 mg). The saponin content was found to be highest in ‘Avial’ mix (6.65 per cent) and lowest in ‘Ularth’ mix (5.00 per cent). The tannin content of ‘Ularth’ mix (11.57 mg) was observed to be on par with ‘Avial’ mix (11.52 mg). Total phenol content was found to be more in ‘Koottu’ mix (21.53 mg/100g) and the total flavonoid content of RTC mixes was seen to be in the range between 0.86-3.25 mg/100g. There was significant difference in the lectin content of ‘Avial’ mix (0.35%), ‘Koottu’ mix (0.56%) and ‘Ularth’ mix (0.75%). Alkaloids and selenium were found to be absent in the RTC mixes. In case of mineral analyses, Copper content was found to be higher in ‘Ularth’ mix (2.57 µg); zinc content was in the range of 4.65-6.55 µg and was found to be higher for ‘Koottu’ mix (6.55 µg) and lower for ‘Ularth’ mix (4.65 µg). Manganese content was found to be higher in ‘Koottu’ mix (5.30 µg) while, it was observed to be on par in ‘Avial’ mix (2.55 µg) and ‘Ularth’ mix (2.51 µg). The highest iron content was found in ‘Ularth’ mix (0.92 µg). Antioxidant activity in the present study revealed that ‘Avial’ mix had the highest DPPH activity with an IC50 value of 33.81 µg/ml. Total antioxidant activity was found to be more for ‘Avial’ mix (41.44 per µg/ml), followed by ‘Koottu’ mix (42.41 µg/ml) and ‘Ularth’ mix (43.45 µg/ml). ‘Avial’ mix showed more ferric reducing capacity while ‘Ularth’ mix had the least capacity in this regard. ABTS radical scavenging activities of RTC mixes ranged between 34.84-46.69 µg/ml. ABTS radical scavenging activity was observed to be higher for ‘Avial’ mix (34.84 µg/ml) and lower values were noted for ‘Ularth’ mix (40.52 µg/ml). Hydroxyl radical scavenging activity of RTC mixes was found to range between 50.55-52.55 µg/ml. ‘Avial’ mix showed higher superoxide radical scavenging activity with an IC50 value of 48.54 µg/ml and the lowest superoxide radical scavenging activity was observed in ‘Ularth’ mix (60.73 µg/ml). However, the highest nitric oxide scavenging activity was observed for ‘Ularth’ mix (14.11 µg/ml) followed by ‘Koottu’ mix (30.92 µg/ml) and ‘Avial’ mix (36.58 µg/ml). Among the three jackfruit based Ready-To-Cook (RTC) curry mixes ‘Avial’ mix was found to have higher antioxidant property and was therefore taken up for studying the anti-cancer property. Cytotoxicity of ‘Avial’ mix was estimated by MTT assay on Human breast adenocarcinoma cells (MCF-7) and 17 per cent of loss in cell viability was observed. Findings of the present study revealed that the jackfruit based RTC mixes comprised of various health promoting components such as beta carotene, ascorbic acid, saponins, tannins, total phenols, total flavonoids and lectins they also had potent antioxidant activities. Thus the curry mixes, in particular the ‘Avial’ mix can be promoted as functional food which will help to enhance its commercialization.
Open Access
Standardization of hydroponics fodder production technology
(Department of Agronomy, College of Agriculture, Vellayani, 2019) Sruthi Liz Thomas; KAU; Usha C Thomas
The study entitled “Standardization of hydroponics fodder production technology” was undertaken during 2017-2019, at College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, with the objectives to identify suitable fodder crops for hydroponics system and to standardize nutrient solution, seed rate and period for harvest. Research work comprised three experiments which was carried out in a low cost hydroponics fodder production system at the Integrated Farming System Research Station, Karamana, Thiruvananthapuram. The crops were grown in a hydroponics machine made of PVC pipes with 2m x 1.3m x 1.8m length, breadth and height with four shelves and automatic sprinkler irrigation system. The first experiment was aimed to evaluate the suitability of fodder crops for hydroponics. The experiment was laid out in completely randomised design and the crops included in the trial were rice (c1), barley (c2), maize (c3), wheat (c4), sorghum (c5), bajra (c6), ragi (c7), cowpea (c8), horse gram (c9) and greengram (c10). The seeds were soaked in 0.1 per cent sodium hypochlorite solution for 12 hours, tied in gunny bag and kept for germination for 24 hours. The seeds were then transferred to trays following a seed rate of 200 g ft-2 (0.22 g cm-2). Among the crops, maize recorded the highest net income and B:C ratio. Considering yield and quality, greengram recorded significantly superior GFY (10.17 kg kg-1seed), protein content (20.97 %), the lowest values for fibre and ash, and a B:C ratio more than one. In sorghum and pearl millet, seed to green fodder yield multiplication was very poor (<3 kg). Finger millet had undesirable characters for hydroponics green fodder like lower values for shoot length, shoot weight, protein content, EE and higher values for fibre and ash. Hence, maize and greengram were identified and selected for the next experiment. The second experiment was done to standardize seed rate and period of harvest of the selected crops. Three different seed rates viz, s1 : 150 g ft-2 (1.61 kg m-2), s2: 175 gft-2 (1.88 kg m-2), s3 : 200 g ft-2 (2.15 kg cm-2) and four different period for harvest viz, t1 : 7 days, t2 : 9 days, t3 : 11 days and t4 : 13 days were adopted. But, in the case of green gram, it was observed that the crop did not survive beyond nine days in hydroponic fodder production system and hence only two periods of harvest viz, t1 and t2 were taken for green gram. Both crops were separately analysed in completely randomised design with two factors. It was observed that maize sown at 200 g ft-2 (s3) and harvested on 11th day (t3) recorded significantly higher values for GFY (6.03 kg kg-1seed) and B:C ratio. While, greengram sown at 200 g ft-2 (s3) and harvested on 7th day (t1) recorded significantly higher values for GFY (10.18 kg kg-1seed) and B:C ratio. Hence, these best combinations of seed rate and period of harvest for both the crops were selected for the next experiment. The third experiment was done to standardize nutrient solution for hydroponics fodder production. The nutrient solutions tested were n1: hoagland solution (0.25%), n2: hoagland solution (0.5%), n3: 19:19:19 (0.5%), n4 : DAP (0.5%) + KCl (0.5%), n5 : starter solution (1:2:1), n6 : vermiwash (10 times dilution), n7 : groundnut cake (supernatant solution) and n8 : water (control), which was sprayed on alternate days from 3rd day. Both crops were separately analysed in completely randomised design. In green gram, spray of hoagland solution (0.25%) (n1) resulted in higher shoot weight, root weight, root length, shoot length and GFY, but the B:C ratio was less than one. Spray of 19:19:19 (0.5%) (n3) recorded on par values with hoagland solution (0.25%) (n1) for shoot weight, root weight, root length, shoot length, GFY and a significantly higher B:C ratio. In maize, spray of hoagland solution (0.25%) (n1) resulted in higher shoot weight, root weight, root length, shoot length and GFY, but a B:C ratio of less than one. The highest B:C ratio was recorded in treatment n8 i.e, water (control). From the results, it can be concluded that both maize and greengram are suited for hydroponics fodder production. Maize grown at a seed rate of 200 g ft-2 with water and harvested on 11th day, and greengram at a seed rate of 200 g ft-2, sprayed with 19:19:19 (0.5%) and harvested on 7th day were found to give the best results considering growth parameters, yield attributes, quality and economics.
Open Access
Screening of pink pigmented facultative methylotroph isolates for water stress tolerance and yield in paddy
(Department of Agricultural Microbiology, College of Agriculture, Vellayani, 2019) Riyas, N K; KAU; Meenakumari, K S
The study entitled “Screening of Pink Pigmented Facultative Methylotroph (PPFM) isolates for water stress tolerance and yield in paddy” was undertaken during 2017-2019, in the Department of Agricultural Microbiology, College of Agriculture, Vellayani, Thiruvananthapuram, with the objective to screen the Pink Pigmented Facultative Methylotroph (PPFM) isolates for water stress tolerance and yield in paddy. The study comprised an in vitro screening experiment and a pot culture experiment with rice variety Harsha. For in vitro screening of PPFM isolates for water stress tolerance, 20 isolates of PPFM from paddy were selected from the previous study of M.Sc. (Ag.) thesis work conducted in the Department of Agricultural Microbiology, Vellayani during 2015-2017 on the basis of carotenoid pigment production, IAA production, proline content, seedling vigour index and yield. These isolates were screened by paper towel method for water stress tolerance under in vitro conditions using mannitol for inducing osmotic stress. There were 21 isolates (20 KAU isolates of PPFM and one TNAU isolate) and four water stress levels (1%, 2%, 3% mannitol and control). The experiment was laid out in completely randomized block design with two replications. Osmotic stress was higher in 3 per cent mannitol treatment. Seeds treated with PPFM 26 recorded the highest germination percentage, shoot length and seedling vigour index. The highest root length and shoot dry weight were observed with the isolate PPFM 15 whereas the highest root dry weight was recorded with PPFM 9. Scoring was done to assess the best five isolates and those with higher ranks were selected for the subsequent experiment. Consequently, PPFM 26, PPFM 15, PPFM 38, PPFM 37 and PPFM 35 which secured ranks from 1 to 5 were selected for the pot culture experiment. The pot culture experiment was undertaken to study the effect of PPFM isolates on growth and yield of paddy under water stress. The experiment was laid out in CRD with 21 treatments and three replications, during summer 2019. The treatments comprised six PPFM isolates (5 KAU isolates of PPFM and one TNAU isolate) and three moisture levels (at field capacity, 75% available water and 50% AW) and three control treatments (0.5% methanol, AMS liquid medium supplemented with 0.5% methanol and absolute control). The treatments were given as seed treatment, seedling root dip and foliar application at 15 and 30 DAT. The study revealed that PPFM isolates had significant effect on biometric parameters, physiological parameters, yield and yield attributes of paddy under water stress. Maximum plant height and leaf area index was recorded with PPFM 38 at 30 DAT and 60 DAT whereas PPFM 37 recorded maximum number of tillers per hill at 60 DAT. Leaf rolling score and leaf drying score were found to be the lowest with PPFM 37 at 30 and 60 DAT. Cell membrane integrity, relative water content, chlorophyll stability index and root dry weight were the highest with PPFM 38 at 30 and 60 DAT. Rooting depth was the highest with PPFM 38 at 30 DAT and PPFM 37 at 60 DAT. Proline content (at all the three moisture levels) and super oxide dismutase (SOD) were significantly higher with PPFM 37 at 30 and 60 DAT. While at 60 DAT, PPFM 37 recorded significantly higher catalase activity at FC and 50% AW, PPFM 38 was found to be superior at 75% AW. Both these isolates were comparable at the different moisture levels. Crop treated with PPFM 37 also recorded the lowest drought susceptibility index. However, peroxidase activity was significantly higher with PPFM 38 at all moisture levels at 30 and 60 DAT. All the PPFM isolates had significant effect on yield attributes and yield of paddy under water stress. Maximum number of panicles per hill, number of grains per panicle (at all moisture levels), grain yield and the lowest relative percentage yield reduction was recorded with PPFM 37. While, PPFM 37 recorded significantly higher number of panicles per hill at FC and 75% AW, PPFM 38 was found to be superior at 50% AW. Both these isolates were comparable at different moisture levels. Though PPFM 37 recorded higher grain yield at all the moisture levels it was on par with PPFM 38. Considering the major drought tolerance parameters such as leaf rolling score, leaf drying score, rooting depth, proline content, SOD, catalase and peroxidase, PPFM 38 was ranked first among the PPFM isolates tested in the pot culture experiment. With respect to the yield attributes and yield of rice under water stress the effect of PPFM 37 and PPFM 38 were observed to be at par. The present study revealed that the isolates PPFM 37 and PPFM 38 (seed treatment 1% PPFM broth culture + seedling dip 2% PPFM broth culture + foliar spray 1% PPFM broth culture at 15 and 30 DAT) were effective in improving the growth, yield and drought tolerance characters of rice.
Open Access
Evaluation of pongamia oil soap against major pests of okra, Abelmoschus esculentus (L). Moench
(Department of Agricultural Entomology, College of Agriculture, Padannakkad, 2019) Anu Thomas; KAU; Sreekumar, K M
The proposed study entitled, Evaluation of pongamia oil soap against major pests of okra, Abelmoschus esculentus (L). Moench was aimed at evaluating the efficacy of a new product made of pongamia oil - pongamia oil soap at different concentrations in combating the major pests of okra viz., shoot and fruit borer, leaf roller and leaf hopper. Laboratory bioassay of pongamia oil soap was carried out in the Department of Agricultural Entomology, College of Agriculture, Padannakkad, during 2018-19 to evaluate the feeding deterrency and growth retardation properties of pongamia oil soap against fourth instar and first instar larvae of bhindi leaf roller, Sylepta derogata respectively and its insecticidal property or repellent property on bhendi leaf hopper, Amrasca biguttula biguttula. The test organisms were exposed to six treatments viz., T1: Pongamia oil soap 0.6%; T2: Pongamia oil soap 1%; T3: Pongamia oil soap 2%; T4: Neem oil soap 0.6%; T5: Soap solution 0.5%; T6: control with three replications under completely randomised design (CRD). Among the different treatments, pongamia oil 2 per cent showed the maximum antifeedent activity on fourth instar larvae and maximum growth retardation activity on first instar larvae of S. derogata. Spraying of pongamia oil soap 2 per cent showed 100 per cent mortality of leaf hoppers by 16 h after the treatment. But neem oil soap 0.6 per cent and pongamia oil soap 0.6 per cent took 24 h to attain 100 per cent mortality. Field efficacy of pongamia oil soap was evaluated by randomised block design (RBD) with seven treatments and four replications on okra variety ‘Arka Anamika’ during rabi and summer seasons at the Instructional farm in College of Agriculture, Padannakkad. The treatments applied were: T1: Pongamia oil soap 0.6%; T2: Pongamia oil soap 1%; T3: Pongamia oil soap 2%; T4: Neem oil soap 0.6%; T5: Soap solution 0.5%; T6: Quinalphos 0.05% - (Standard check); T7: Control. All treatments were applied once at vegetative stage and twice during reproductive stage. Observations were taken one day prior to treatment and 1, 3, 5, 7 and 14 days after treatment (DAT) for sucking pests. Damage symptoms caused by lepidopteran pests were observed one day prior to and 7 and 14 DAT. After three sprays during the rabi season pongamia oil soap 2 per cent was superior among botanicals in reducing the leaf hopper population significantly as compared to that of control. The effectiveness against leaf hopper lasted up to seven days after treatment. By the end of the rabi season pongamia oil 2 per cent showed significant reduction in damaged leaves as compared to other botanicals whereas the damage per cent was significantly increased in control and soap solution 0.5 per cent. Damage caused by leaf roller was cut down by the treatment of pongamia oil soap 2 per cent for seven days due to its antifeedent, repellent and growth retardation activity. Mean percentage of shoots and fruits infested by okra shoot and fruit borer Earias vitella and fruit borer Helicoverpa armigera during rabi and summer season was observed lowest in pongamia oil 2 per cent among botanicals. Reduction in mean per cent of fruit and shoot damage by pongamia oil soap may be due to the feeding deterrency of pongamia oil which remained effective for seven days. However all the treatments were effective in reducing the pest infestation except soap solution 0.5 per cent. Effectiveness of pongamia oil soap was observed to decline after seven days after spray application. Higher concentration of the soap gave better results as compared to that of lower concentrations. Pongamia oil soap 2 per cent exhibited increased fruit yield and marketable yield as compared to that of control due to lower incidence of pests during both the seasons. Economics of pongamia oil soap 2 per cent in turns of cost benefit ratio was also high as compared to control in both rabi and summer seasons, making it an effective component in IPM programmes and organic farming.
Open Access
Evaluation of micronutrient formulation in cowpea
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Padannakkad, 2019) Roshni John; KAU; Binitha, N K
The project “Evaluation of micronutrient formulation in cowpea (Vigna unguiculata L. Walp)” was carried out at College of Agriculture, Padannakkad and Regional Agricultural Research Station (RARS), Pilicode during 2017 to 2019. The objectives of the study were to evaluate the effect of micronutrient formulation through seed treatment and foliar nutrition on growth, nodulation and yield of cowpea and to study its effect on plant nutrient uptake and residual soil nutrient status. Laboratory study was carried out at COA, Padannakkad to formulate and standardize the micronutrient solution for cowpea. Different concentrations of the standardized micronutrient formulation were used for seed treatment study (Experiment 1). The experiment was carried out in completely randomized design with 7 treatments and 3 replications which included seed treatment with micronutrient formulation @ 0.25, 0.50, 0.75, 1, 1.5 and 2 per cent as T1, T2, T3, T4, T5 and T6 respectively. T7 (seed treatment with water) was the control. Observations on germination percentage, number of days taken for germination, seedling length at three leaf stage and seedling vigour index were recorded. Treatment T6 (micronutrient formulation @ 2 %) showed highest seedling length (24.23 cm) and seedling vigour index (2423) which was followed by T5 (micronutrient formulation @ 1.5 %). Thus the best and second best treatment from seed treatment study was concluded as T6 and T5 respectively and was selected for the field experiment (Experiment 2). The field experiment was conducted in randomized block design with 12 treatments replicated three times. The treatment consisting of combination of four levels of seed treatment (no seed treatment, seed treatment with rhizobium, seed treatment with best concentration from experiment 1 and second best seed treatment from experiment 1) and three levels of foliar application of micronutrient (no foliar application, one foliar application at 15 DAS and two foliar applications at 15 and 30 DAS). Biometric observations were recorded at flower bud initiation and at harvest. Plant height at flower bud initiation and at harvest was superior in S3 (Seed treatment with micronutrient formulation at 2 %) while stem diameter was highest in S4 (seed treatment at 1.5 %) and S3 respectively in both stages. Double foliar spray was superior in plant height and stem diameter at both stages. Interaction S3F3 (2 per cent seed treatment plus two foliar spray) recorded highest plant height at both stages and stem diameter was highest in S2F3 (treatment with rhizobium plus two foliar spray). Number of nodules was highest in S2 (seed treatment with rhizobium). Number of pods per plant (21.02 & 20.97), pod weight per plant (36.14 g & 33.49 g), grain yield (2224 kg ha-1) and dry matter production (2292.91 & 2372.92 kg ha-1) was superior in S3 and F3 (two foliar spray). Interaction S3F3 was superior in number of pods per plant (25), pod weight per plant (38.11 g), grain yield (2320 kg ha-1) and dry matter production (2613.24 kg ha-1). Leaf analysis revealed that P and K content in leaf was highest in S3. N, P, K and Ca content in leaf was highest in F3. Interaction S3F3 recorded highest N, P and K content in cowpea leaf. Mg content was highest in S2F3 (treatment with rhizobium plus two sprays). Fe, Mn, Zn and B content in leaf was highest in S3 and F3. Interaction S3F3 (2 per cent seed treatment plus two foliar spray) recorded highest Fe, Mn and Zn content in cowpea leaves. The uptake of N, P, K, Ca, S, Fe, Mn, Zn and B were highest in both S3 and F3 whereas Mg uptake was highest in S3 and F2 (one foliar spray). Cu uptake was highest in F3. Interaction S3F3 recorded highest uptake of N, P, Mn and Zn. N content in cowpea grain was superior in S2 and F3. While K, Ca, Fe, Mn, Zn, Cu and B content in cowpea grain was highest in both S3, F3 and interaction S3F3. In case of interaction, N was highest in S2F3. The uptake of N, P, K, Ca, Mg, S, Fe, Zn and B in cowpea grain was highest in both treatments S3 and F3 and the interaction, S3F3 recorded highest uptake of P, K, Ca, Fe, Mn, Zn and B in grain. Studies on residual soil nutrient status revealed that available N and P in soil was highest in S2 at both 45 DAS and at harvest. Available K was highest in S3, F3 and S3F3 at both stages. Organic carbon content was found to increase in plots receiving two foliar spray and interaction S3F3. Available Fe, Mn and Zn was highest in S3 at harvest and in F3 at both stages. Available B was highest in S3 and F3 at 45 DAS while Mo at harvest. B and Zn were highest in S3F3 at 45 DAS while at harvest available Fe was found to be higher in S3F3. Available Fe at 45 DAS was highest in S1F3 (no seed treatment plus two foliar spray). Root CEC was superior in S3, F3 and in interaction S3F3. The results obtained from the investigation revealed that the application of micronutrient formulation as two foliar spray (15 and 30 DAS) along with seed treatment (2 per cent) was found to be highly effective in increasing the growth and yield characters of cowpea. The uptake of nutrients in cowpea leaf and grain was also found to increase with the application of micronutrient formulation enhancing the nutritional quality of grain.
Open Access
Productivity enhancement of rice based cropping system with pulses
(Department of Agronomy, College of Agriculture, Padannakkad, 2019) Adarsh, S; KAU; Jacob John
The project “Productivity enhancement of rice based cropping system with pulses” was undertaken with the objective of assessing the suitability of different pulse crops for summer fallows of double cropped lowland rice fields under varying nitrogen levels and its residual effect on the succeeding virippu rice crop. The experiment was laid out in Randomised Block Design with thirteen treatments and replicated thrice, during summer 2017-18 and virippu 2018-19 seasons. The treatments were T1 (cowpea with 100 % recommended dose of nitrogen (RDN)), T2 (cowpea with 75 % RDN), T3 (cowpea with 50 % RDN), T4 (black gram with 100 % RDN), T5 (black gram with 75 % RDN), T6 (black gram with 50 % RDN), T7 (green gram with 100 % RDN), T8 (green gram with 75 % RDN), T9 (green gram with 50 % RDN), T10 (red gram with 100 % RDN), T11 (red gram with 75 % RDN), T12 (red gram with 50 % RDN) and T13 (fallow during summer). The varieties of cowpea, black gram, green gram, red gram and rice used were PGCP 6, Co 6, Co 8, APK 1 and Uma respectively. The growth parameters, yield attributes, nutrient uptake, soil available nutrient status were recorded and economics was worked out during summer and virippu seasons. Physiological parameters of crop, composition of weeds, absolute density of weeds and nutrient removal by weeds were assessed during summer season. During summer, the height of cowpea (100 % RDN) and green gram (75 and 50 % RDN) was found superior. The number of branches per plant was found higher in cowpea (T1 and T2). Leaf area index (100 and 50 % RDN) and crop growth rate (50 % RDN) was superior in cowpea. The number of pods were significant in green gram (75 and 50 % RDN). The yield was significantly high in cowpea (50 % RDN) and it was on par in red gram. Broad-leaved weeds dominated, followed by sedge and grasses. Among grasses, sedge and broad-leaved weeds; Oryza sativa, Cyperus rotundus and Boerhavia diffusa dominated respectively. Absolute density of weeds was lesser in T11 and T12. Black gram (50 % RDN) was effective in smothering weeds. The dry matter production of weeds was highest in fallow during summer. The N and P uptake was on par in cowpea (100 and 50 % RDN) and green gram (75 and 50 % RDN). The K uptake was higher in cowpea (50 % RDN). The N removal by weeds was higher in fallow and that of P and K were on par in all treatments. The available soil nutrients showed no difference after summer crop. Gross income, net income, and B:C ratio were higher for red gram. During virippu, growth attributes, yield, and yield parameters were on par in all treatments in rice. The thousand grain weight was highest in plots where cowpea and green gram with 100 per cent RDN were grown during summer. The N uptake of rice was significant with red gram (75 % RDN). The available soil nutrients were on par in all treatments in rice. The economic parameters viz., gross returns, net returns, B:C ratio were on par among all treatments in rice. The following conclusions, which meet the objectives, can be arrived at from the study: • During summer, cowpea and red gram performed better among the different pulses, in terms of yield. However, regarding gross income, net income and B:C ratio, red gram ranked first. • There was no significant difference in yield, gross income, net income and B:C ratio of pulses under varying levels of N, thereby indicating that the lower level of N (50 % RDN) will be sufficient. It is also logical to infer that the residual effect of the preceding two crops of rice contributed to reduce N dose when pulses are raised during summer in double cropped lowlands. • Reducing the dose of N for the summer crops did not have any adverse effect on the succeeding virippu rice crop as evident from the on par yield and economics among different treatments.
Open Access
Dynamics of carbon stock in rice based farming systems of kari soils
(Department of Agronomy, College of Agriculture, Padannakkad, 2019) Chethankumar, S; KAU; Devi, V S
An investigation entitled “Soil carbon dynamics in a rice based cropping system” was carried out with the objective of assessing and comparing the soil carbon dynamics in different rice based cropping systems viz., rice-rice-maize (R- R-M), rice-rice-bhindi (R-R-B) and rice-rice-daincha (R-R-D) in a lowland riverine alluvium. The investigation was undertaken at College of Agriculture, Vellayani and Integrated Farming System Research Station (IFSRS), Karamana during 2017- 19. At IFSRS, rice based cropping sequence viz., rice (Virippu) - rice (Mundakan) - maize+ bhindi+ daincha has been practicing since 2011-12. The study was undertaken during three seasons of 2018-19 as three experiments. For experiments 1 (Virippu) and 2 (Mundakan), medium duration rice variety, Uma was cultivated. Surface soil (0-15 cm) samples were collected after each crop harvest and analyzed for soil physical, chemical and biological properties and carbon fractions. The results were compared with that of rice- rice- fallow (R- R-F) sequence. All the carbon fractions (total organic carbon [TOC], particulate organic carbon [POC] - >53 and <53 µm) except labile carbon [LC] slightly increased after Mundakan crop. On an average, TOC and POC increased by 5.9 and 5.24 per cent, respectively. There was not much variation in soil bulk density (BD), EC, available K, Ca, Mg, S, Fe, B and microbial count during both the seasons. The pH slightly increased after Mundakan, with the highest value for R-R-F (5.14) and R-R-B (5.22) sequences during Virippu and Mundakan, respectively. Available N, P, Mn, Zn, Cu, microbial biomass carbon (MBC) and enzyme activities (dehydrogenase, urease and acid phosphatase) declined nominally after Mundakan season. The lowest enzyme activities were recorded in R-R-F sequence, during both the seasons. Both paddy grain and straw were analyzed for major, secondary and micronutrients. R-R-D sequence had recorded the highest grain N (1.98 per cent) content after Virippu. K content was also highest for R-R-D sequence, after both Virippu (1.09) and Mundakan (1.42) seasons. Highest P and Ca contents were obtained with R-R-M and R-R-B sequence, respectively, after both the seasons. Micronutrient content of grain and straw were almost the same in all the systems, after both Virippu and Mundakan, Economic yield was highest for R-R-B (5.21 t ha-1) and R-R-D (4.09 t ha-1) sequence after Virippu and Mundakan, respectively. During the summer season (experiment 3), field was divided into three equal parts and planted with maize (var. Co 6), bhindi (var. Manjima) and daincha (var. TN local), respectively. Daincha at 50 per cent flowering stage and maize leaves after crop harvest were incorporated into the field. Soil samples were drawn at 15 cm intervals up to 105 cm depth and analysed for major soil parameters and carbon fractions. Plant samples were analysed for major, secondary and micro nutrients. Economic and biomass yield of R-R-B and R-R-M sequence were 9.21 and 25.1 t ha-1 and 3.6 and 7.89 t ha-1, respectively. Biomass yield of R-R-D sequence was 22.5 t ha-1. The cropping systems significantly influenced soil carbon dynamics. R-R- D sequence recorded 10, 14, 13 and 22 per cent increase in TOC, LC, POC and MBC, respectively, up to 105 cm depth compared to that of R-R-F sequence at the end of cropping cycle. Enzyme activities (dehydrogenase, urease and acid phosphatase) showed significantly higher positive correlation with the carbon fractions. Among the weather parameters, atmospheric temperature (both minimum and maximum) was found to be positively correlated with soil carbon dynamics. The role of crop residue incorporation in improving soil carbon dynamics was clearly understood from the carbon management index (CMI) value, which was highest in R-R-D (120.56) followed by R-R-M (109.31), R-R-F (106.79) and R-R- B (72.81). Except BD and available Fe and Mn, all the other soil parameters showed a declining trend with soil depth. BD ranged from 1.19 to 1.62, 1.21 to 1.73, 1.17 to 1.72 and 1.2 to 1.65 g cm-3 for R-R-B, R-R-M, R-R-D and R-R-F systems, respectively. Available Fe and Mn increased upto 30 cm depth and thereafter declined. R-R-D system resulted in the highest soil available N, K, Ca, Mg, S, B, MBC, urease, acid phosphatase, TOC, LC and POC upto 30 cm depth. pH and EC increased by 9.3 and 77 per cent, respectively in R-R-M system. Available P and Ca in the surface layer declined in R-R-B and R-R-M systems compared to R-R-F. Available Fe and Mn contents were reduced in the all systems except R-R-F. The R-R-B system had the highest available Zn and Cu compared to R-R-F (8 and 13 per cent, respectively). Microbial load, enzyme activities and MBC were negligible beyond 75 cm depth. Daincha recorded the highest N (1.47) and P (1.13) content, while the highest K (1.96), Ca (0.85) and Mg (0.21 per cent) were in bhindi. The study revealed that, among the different rice based cropping systems, R-R-D system influenced soil carbon dynamics most significantly followed by R- R-M, thereby indicating the role of crop residue incorporation particularly, green manures in improving the soil carbon sequestration potential and consequently soil health.
Open Access
Matrix based slow release fertilizer for increasing nutrient use efficientcy in the onatukars sandy plains
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2019) Adithya G Raj; KAU; Mini, V
A study on "Matrix based slow release fertilizer for increasing the nutrient use efficiency in the Onattukara sandy plain" was carried out during 2017-2019 in the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani. The objective of the study was to develop low-cost matrix based slow release fertilizer using local biodegradable agro waste and to evaluate the effect of this slow release fertilizer in increasing nutrient use efficiency in the sandy loam soils of Onattukara. The study comprised three parts viz., development of matrix based slow release fertilizer, incubation study and evaluation of the effect of matrix based slow release fertilizer in increasing nutrient use efficiency. Different combinations of biodegradable locally available materials like rice husk ash, clay, cow dung, rice husk, coirpith compost, vermicompost and neem cake were used to develop a suitable matrix. The matrix with 1: 1: 0.5: 0.5: 0.5: 0.5: 0.5 composition was selected based on its high pH, low electrical conductivity and low cost of production. The stability and dissolution was also studied imder controlled condition. The best combination of matrix (1: 1: 0.5: 0.5: 0.5: 0.5: 0.5) was selected to entrap fertilizers at various proportions of matrix: fertilizer viz., 1:1, 2:1, 0.5:1 and matrix alone. Granular and disc forms of these combinations were developed and used for incubation for a period of two months to study the nutrient release pattern of N, P and K. Soil samples were collected at 15 days interval for nutrient analysis. The nutrient release pattern was different for N, P and K. The 2: 1 (matrix: fertilizer) granular formulation was selected based on the gradual release pattern and the highest peak of nutrient availability of N, P and K even after 2 months. Effect of matrix based slow release fertilizer in increasing nutrient use efficiency was evaluated by using tomato variety Vellayani Vijay as test crop and the pot culture experiment was conducted at Onattukara Regional Agricultural Research Station, Kayamkulam during November,2018 - January,2019. The 2:1 granular formulation was selected for entrapping NPK fertilizers for the pot culture X experiment.The experiment consisted of ten treatments and they were Ti (Recommended dose of fertilizers and organic manure as per POP), T2 (Recommended dose of fertilizers as basal application),T3 (Recommended dose of fertilizers in two splits),T4 (Matrix entrapped recommended dose of fertilizers as basal application), Ts (Matrix entrapped recommended dose of fertilizers in two splits),T(6 Matrix entrapped 75 % of recommended dose of fertilizers as basal application),T(7 Matrix entrapped 75% of recommended dose of fertilizers in two splits),T8( Matrix entrapped half dose of recommended dose of fertilizers as basal),T9 (Matrix entrapped half of recommended dose of fertilizers in two splits) and T10 (Matrix alone). Growth, yield and quality of tomato increased significantly due to the application of organic matrix based fertilizers. The highest plant height (35.6 cm) was recorded in the treatment T9 and was on par with Ti, T3, Ts and T7.The treatments did not show a significant influence on number of branches per plant, days to first flowering and days to fruit set. Treatment T9 recorded the highest fhiit set percentage (80.3%) which was on par with treatments Ti, Ts, and T7.The treatment T9 recorded the highest value for all the yield attributes and yield. The highest number of fruits per plant (32.3) and yield per plant (0.79kg) was recorded by treatment T9 and was on par with Ti, Ts and T7. For fhiit weight, treatment T9 was found to be on par with all other treatments except treatment Tlo.The treatment T9 recorded the highest value for the quality parameters such as TSS (5.33 %) and ascorbic acid (22.3 mg lOOg"'). The treatments did not show any significant influence on Lyeopene content of fruit. Soil analysis after the experiment showed that the pH increased from the initial value of 5.28 to the highest value of 5.98 which was recorded for the treatment T10 and was on par with all treatments except Ti, T2 and T3. The treatments with matrix entrapped fertilizers recorded a higher pH as compared to the treatments without matrices. The highest value of EC (0.68 dS m ') was recorded by Ts. The treatment did not show a significant influence on organic carbon content. In the ease of primary nutrients, for both available N and K, treatment Ts recorded the highest status (250.9 kg ha"' and 103 215.8 kg ha"') and was on par with T4, Te, T? and T9. Available P status was the highest in Ts (53.37 kg ha"') and was on par with treatment T4, Te, T?, Tg and T9. The highest value for exchangeable Ca (248.89 mg kg"') and Mg (60 mg kg"') was recorded for treatment Ts which was significantly superior to all other treatments. Treatment Ts recorded the highest value for available B (0.281 mg kg"') and Zn (0.519 mg kg"') also and was on par with T4, Te, T?, Tg, T9 and Tio. The results of the plant and fiaiit analysis revealed that the treatment T9 recorded the highest value for N, P and K content in index leaf (2.78% , 0.195% and 1.77%), plant (2.14%, 0.538% and 2.62%) and fhiit (3.69 %, 0.555% and 2.20 %), respectively, which was on par with Ti, Ts and T7. In the case of Ca, Mg, Zn and B content, the treatment T9 recorded the highest value for index leaf (0.186 %,0.168% , 16.15 mg kg"' and 4.9 mg kg"'), plant (0.149%, 0.165% ,15.81 mg kg"' and 4.4 mg kg"') and fruit (0.157%, 0.149%, 16.89 mg kg"' and 1.35 mg kg"'), respectively and was on par with all other treatments except Ti, T2 and T3. Treatments did not show any influence on S, Fe, Mn and Cu content in index leaf, plant and fiaiit. There was no incidence of major pest and disease in the crop. Treatment T9 recorded the highest net income (Rs.230097/-), B: C ratio (2.1) and nutrient use efficiency. From the investigation it can be concluded that, treatment T9 (Matrix entrapped half of recommended dose of fertilizers in two splits) was the best treatment in which the yield increased by 13% compared to POP recommendation and B: C ratio increased from 1.69 to 2.1. Organic matrix based slow release fertilizer was found to be effective under Onattukara condition for increasing the nutrient use efficiency from 18% to 44%. Fifty per cent reduction in the recommended dose of fertilizer was achieved by this matrix based slow release fertilizer formulation. This slow release fertilizer technology reduced the cost of cultivation and leaching loss of nutrients and increased the nutrient use efficiency and yield in the Onattukara sandy plain.
Open Access
Breeding for drought tolerance in cocoa (Theobroma cacao L.)
(Department of Plant Breeding and Genetics College of Horticulture, Vellanikkara, 2019) Juby, Baby; KAU; Minimol, J S
Drought is considered to be one of the most limiting factors for cocoa production. Preliminary efforts have been made in Kerala Agricultural University to identify drought tolerant cocoa genotypes. In continuation of the same, the present study was proposed to develop superior hybrids tolerant to drought in cocoa. The study was conducted at Department of Plant Breeding and Genetics, College of Horticulture (CoH), Cocoa Research Centre and College of Forestry, KAU. Four genotypes viz. M 13.12, G I 5.9, G II 19.5 and G VI 55 identified as drought tolerant in previous study were taken as parent materials. They were hand pollinated in all possible combinations. Hybrid pods were obtained in all the crosses except in G VI 55 x M 13.12 and successful crosses showed more than 85 per cent germination. Since initial vigour was found to be correlated with final yield, the seedlings were screened at the third month stage for their Height x Diameter² (HD²) value. Based on the seedling vigour, 1505 hybrids were screened representing all the crosses. During the fifth month, they were screened for drought tolerance by maintaining the soil at 40 per cent field capacity for two weeks and a total of 120 hybrids were selected. Based on the percentage of leaves retained on the hybrids, the plants were classified into four categories: 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). Hybrids maintained under full irrigation were taken as control. Various biochemical and physiological parameters related to drought were observed. Proline, glycine betaine and superoxide dismutase were found to be high in tolerant and highly tolerant hybrids and was low in susceptible hybrids. The control was found to have very less amount of proline, glycine betaine and SOD. However, under drought conditions, plants showed reduced nitrate reductase activity. The control plants showed highest nitrate reductase activity. In case of physiological parameters, high chlorophyll stability index, membrane stability, relative water content, photosynthetic rate and chlorophyll content were recorded in all tolerant and highly tolerant hybrids whereas these parameters were comparatively low in susceptible hybrids. The control plants showed high value for all these characters. However, in case of transpiration rate, a reverse trend was observed. The highly tolerant and tolerant hybrids showed low transpirational rate, whereas the susceptible hybrids had high transpirational rate. The control also had high transpirational rate. It indicated the ability of tolerant hybrids to conserve water during drought stress. The leaf temperature did not show any variation among the hybrids. Correlation studies showed that all physiological and biochemical characters except transpiration rate and leaf temperature have positive correlation with percentage of leaves retained. Effect of these characters on dependent variable i.e., percentage of leaves retained was estimated by path analysis. Characters having direct effect on leaf retention were proline, nitrate reductase activity, membrane stability, photosynthetic rate and relative water content. These characters were analysed for their genetic parameters. It was found that except membrane stability, all other charcters were having high heritability and genetic gain. Among the four characters considered, proline, nitrate reductase activity and relative water content were having additive gene action and hence, were suitable as selection parameters for population improvement and heterosis breeding. Photosynthetic rate which was having comparatively less additive gene action, can be exploited in heterosis breeding. Based on these four characters, a selection criteria was designed (Proline, > 410 µg/g, NRA, > 6 mmol nitrate/g/hr, RWC, > 40% and Photosynthetic rate, > 0.700 µmol CO2 m-2 s-1). Three characters which expressed high additive gene action, were subjected to binomial regression analysis and was found that if nitrate reductase activity when used as a selection criteria, population will experience 87.48 per cent improvement over base population. Similarly, 51.87 per cent and 51.55 per cent improvement will be there with the characters relative water content and proline respectively. Combining ability studies indicated that the best general combiners were G VI 55 and G II 19.5 and the best specific crosses were M 13.12 x G II 19.5, G I 5.9 x G VI 55 and G II 19.5 x G VI 55. The 120 hybrids used in the study are now field planted. They have to be evaluated at their various stages of growth by subjecting to drought stress. For resistant breeding studies, 120 hybrids will not form substantial volume. Hence, more hybrids have to be evolved by using selected best combiners.

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