Browsing by Author "Mohanakumaran, N"

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Device for bagging cocoa flowers
(Kerala Agricultural University, 1987) Rajamony, L; Mohanakumaran, N
Effect of ethrel, 2,4-D and MH on growth, rhizome yield and diosgenin content in costus spec/os us (Koening) smith
(Kerala Agricultural University, 1994) Satheeshan, K N; Mohanakumaran, N
An experiment to study the effect of ethrel, 2,4-D and MH on the growth, rhizome yield and diosgenin content in Costus speciosus was conducted at the College of Horticulture, Vellanikkara. Plant height was significantly reduced by ethrel and MM at the levels tried. Ethrel 100 and 200 ppm significantly increased the number of tillers per plant. The length, width and leaf area and internodal length of shoot was significantly reduced by ethrel treatments while total leaf area was higher in plants treated with 2,4-D (10 and 20 ppm). Ethrel 200 ppm recorded maximum yield of green and dry rhizomes. Diosgenin content of the rhizome was found to be the highest in the plants treated with 2,4-D 10 ppm. Shoot/rhizome ratio was significantly reduced by Ml I treatments.
Effect of growth regulators on the yield of tomatoes
(Kerala Agricultural University, 1974) Manikantan Nair, P; Mohanakumaran, N; Ramachandran Nair, V
Effect of growth substances on the growth, rhizome yield and diosgenin content in Costus speciosus
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1984) Satheeshan, K N; Mohanakumaran, N
An experiment was conducted at the College of Horticulture, Vellanikkara to study the influence of ethrel (100, 200 and 300 ppm), 2, 4-D (10, 20 and 30 ppm) and MH (50, 100 and 150 ppm) on the growth, rhizome yield and diosgenin content in Costus speciosus. Plant height was significantly reduced by the three levels of ethrel (100, 200 and 300 ppm) and MH (50, 100 and 150 ppm) more evidently on the 110th and 140th day after planting. Ethrel 100 and 200 ppm and MH 50 ppm significantly increased the number of tillers per plant on the 110th and 140th day. Leaf production per tiller was significantly increased by 2, 4-D 10 ppm on the 80th day and was significantly reduced by ethrel 100 and 200 ppm on the 140th day after planting. The length, width and area of the leaves and the intermodal length of shoot was significantly reduced by ethrel treatments. Individual and total leaf area in general was significantly higher in plants treated with the two lower levels of 2, 4-D (10 and 20 ppm), on the stages observed. Ethrel, at the three levels tried, significantly increased the dry matter content of shoots. The shoot/rhizome ratio was reduced significantly by ethrel and MH. The girth of main rhizome was increased significantly by ethrel 100 and 200 ppm. The number of primary fingers was significantly increased by ethrel 100 and 200 ppm and 2, 4-D 10 and 20 ppm and its length was significantly increased by ethrel 200 ppm. The number of secondary finger was significantly higher in ethrel 100 and 200 ppm and MH 150 ppm treatments. Ethrel 200 ppm recorded the maximum yield of green and dry rhizomes. Significant increase in the yield of green rhizome was also given by ethrel 100 ppm and 2, 4-D 10 and 20 ppm. The diosgenin content of the rhizomes was maximum in 2, 4-D 10 ppm (1.83 per cent), but the yield of diosgenin per ha was maximum in ethrel 200 ppm. Significant increase in diosgenin yield was also obtained in ethrel 100 ppm, 2, 4-D 20 ppm and MH 50 ppm. The greatest return per ha was given by ethrel 200 ppm, followed by ethrel 100 ppm and 2, 4-D 10 ppm.
Effect of N, P and K on the growth of Costus speciosus (Koening) Smith
(Kerala Agricultural University, 1987) Sudhadevi, P K; Mohanakumaran, N
A field trial was conducted to find out the role of major nutrients on different growth characters of Costus speciosus and the important characters which had a bearing on diosgenin yield were identified. The results showed that N application increased the growth of plants in terms of height, length and breadth of leaves, area per leaf and total leaf area per plant. P had a depressing effect, especially on the number of leaves and area per leaf. The beneficial effect of K was only marginal, as compared to that of N. Application of N increased the yield of rhizomes. The diosgenin content of the rhizomes was found to be significantly influenced by N, P and K application while the yield of diosgenin was significantly influenced by different levels of N and K. Of the growth characters studied, the total leaf area and plant height were found to be significantly correlated with diosgenin yield.
Effect of plant growth substances on the in vitro propagation of jack (Artocarpus Heterophyllus Lam.)
(Kerala Agricultural University, 1988) Rajmohan, K; Mohanakumaran, N
Explants from shoot apices of fresh stem sprouts of five-year old jack (Artocarpusheterophyllus Lam.) trees registered a multiplication rate of 4.5 x. when cultured for five weeks on MS proliferation medium containing BA (5 mg/l) and NAA (0.2 mg/l). The normal strength of inorganic salts and organic growth factors of the MS medium, with 30—40 g/l of sucrose or 20—30 g/l of glucose was found to support the multiplication and growth of the cultures. GAa did not influence the shoot proliferation or growth. Adenine sulphate at 20 mg/l was found to increase the multiplication rate by 27.3 per cent, without
Effect of planting date, weight of rhizome and spacing on the growth, yield and quality constituents on turmeric (Curcuma longa L.)
(Department of Horticulture (Plantation crops and spices), College of Horticulture, Vellanikkara, 1983) Chatterjee, R K; Mohanakumaran, N
A split-split plot experiment was conducted during 1981-82 at the College of Horticulture, Vellanikkara using Kasturi Tanuka as the test variety with a view to arriving at the optimum time of planting, spacing and weight of planting material mat can be advocated for commercial cultivation of turmeric. The treatments were early Hay, middle of May and early June planting, 10 x 20 cm, 15 x 20 ea and 20 x 20 cm spacing sad 20 g, 40 g and 60 g weight of the planting aaterial. She crop performance was analysed based on germination, growth and yield parameters. She percentage germination was higher for the early June planted crop with 20 x 20 ca spacing and 60 g planting material. It was observed that the giant growth characters like number of leaves per plant and mean leaf area were significantly influenced by all the three treatments. She height of the plant as well as the length of mother rhizomes were significantly influenced by time of planting and weight of planting material. She effects of spacing and weight of planting material were manifested significantly in the tiller production.
Effect of planting date, weight of rhizome and spacing on the growth, yield and quality constituents on turmeric (Curcuma longa L)
(Department of Horticulture (Plantation Crops & Spices), College of Horticulture, Vellanikkara, 1983) Chatterjee, R K; Mohanakumaran, N
Effects of graded doses of nitrogen , phosphorus and potassium on the growth and leaf nutrient status in cocoa
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1981) Salikutty Joseph; Mohanakumaran, N
Investigations were carried out at the College of Horticulture , Vellanikkara during 1979-80 to study the effect of graded doses of nitrogen , phosphorus and potassium on the growth and leaf nutrient status of cocoa . The results of a pot culture experiment in completely Randomised Design revealed that growth parameters (height, girth and number of leaves) as well as dry matter production remained unaffected following the application of nitrogen , phosphorus and potassium. The studies indicated that addition of fertilisers to seedling grown in potmixture may not be necessary . It has also been observed that the uptake of nitrogen , phosphorus and potassium by cocoa seedlings was not affected by varying levels of these nutrients. Leaf ranked fifth from the apwas found to be suitable for leaf analysis in cocoa seedlings. Field grown young cocoa trees were utilised for evaluating the relationships between soil test values and leaf nutrient concentration vis a vis plant growth.The studies indicated the suitability of either fan or chupon leaves for foliar nutrient analysis in cocoa. However, indiscriminate sampling between the two types is to be avoided . No significant correlations existed between phosphorus and potassium contents in soil leaf, and tree growth.
Enhancing sucker production In banana and Its effect on the bunch weight of the mother plant
(Department of Horticulture, College of Agriculture, Vellayani, 1986) Lekha Sreedhar, R; Mohanakumaran, N
Natural sucker production in seven .of the important cultivars of the State was assessed at the College of Agriculture, Vellayani during 1983-85* Attempts were also made to standardise a treatment/treatment combination that would generate a large number of comrmerciably acceptable suckers in 'Robusta' without much deleterious effects on the mother plants. Among the seven cultivars, ’Nhalipoovan* produced significantly larger number of suckers per mat (12.40 against 3.72 to 5.94). The natural sucker production in 'Robusta' was found to be fairly low (4.59 per mat against 12.40 per mat in 'Nhalipoovan
Flower bud differentiation in Piper sp.
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1985) Rajan, P S; Mohanakumaran, N
Studies were undertaken at the College of Horticulture, Vellanikkara during 1983-’84 in Panniyur-1 and Karimunda varieties of pepper to collect information on the factors influencing flower bud differentiation and on the histological aspects of the process. Among the climatic factors maximum and minimum temperature during the preceding summer as well as the monsoon showers exhibited significant positive correlation with flower bud differentiation process. Among the nutritional factors studied, carbohydrates and C/N ratio were found to be high prior to the peak differentiation period. However, these failed to show significant statistical correlation. Significant accumulation of nitrogen was found in the shoots prior to differentiation. Phosphorus and potassium contents were not correlated with the process. Inhibitor content of the shoots prior to differentiation was found to negatively influence the process. Peak period of differentiation was observed from the middle of June to the end of July in Panniyur-1, while it was a little advanced in Karimunda (from the beginning of June to the middle of July). There were no fundamental differences in the histological aspects of flower bud differentiation between the two varieties. The bud which was conical during the vegetative phase changed into a dome shaped structure during the transition. Afterwards, this grew into a cylindrical structure on the sides of which bract and flower primordial developed in aeropetal succession. Differentiation and development of ovary wall, integuments, ovules, pollen sacs, pollen grains etc. followed. The whole process of differentiation was completed within about 25 days of its commencement.
Heterosis in chilli (Capsicum annum L.)
(Kerala Agricultural University, 1986) Manikantan Nair, P; Mary K George; Mohanakumaran, N
An experiment was laid out in 1979 at the Department of Agricultural Botany, College of Agriculture, Vellayani to study the heterosis in Capsicum annum L. Nine parents and 36 F1 hybrids were compared. Eighteen economic attributes including vitamin A, vitamin C, capsaicin and oleoresin content were studied. All the characters under investigation manifested heterosis over midparental values though there was wide variation for different traits in different cross combinations. Maximum heterosis was noticed for number of primary bradches and vitamin C content. A comparison of average heterosis for various characters revealed that number of secondary branches topped the list followed by vitamin C, capsaicin content and number of primary branches. The studies identified two promising hybrids with desirable attributes namely Purple Round x Vellanotchi and Pant C1 x Purple Cluster. Negative heterosis was noticed for two important economic attributes namely number of days taken for blooming and number of seeds per fruit. For nutritive and quality characters very little expression of hybrid vigour in vitamin A content was noticed. However, there was considerable manifestation of hybrid vigour in vitamin C and oleoresin content.
In vitro rooting of jack shoot cultures
(Kerala Agricultural University, 1983) Rajmohan, K; Mohanakumaran, N
Induced mutations in ginger (Zingiber Officinale R.)
(Department of Horticulture, College of Agriculture, Vellayani, 1989) Jayachandran, B K; Mohanakumaran, N
Investigations in ginger cv. Rio-de-Janeiro, were carried out during 1985-89 for studying the effect of gamma rays and ethyl methane sulphonate (EMS) on the growth, yield and flowering in the VM1 generation, for assessing the variability including tolerance/resistance to bacterial wilt and soft diseases in the VM2 and for studying the VM3 progenies of the desirable VM2 plants. Dose standardization studies using 10 doses of gamma rays (from 0.5 to 5.0 krad) and 11 doses of EMS (from 8 to 150 mM) revealed that the LD50 for sprouting and survival was between 0.5 and 1.0 krad gamma rays and below 8 mM EMS. For the VM1 study, five doses each of gamma rays (0.5 to 1.5 krad) and EMS (2 to 10 mM) were used. Delayed sprouting occurred to a limited extent. Sprouting, survival, plant height, number of tillers and leaves, and rhizome yield decreased as the doses of the mutagens increased. In general, there was a tendency for recovery of growth parameters as the growth phase advanced. The number of plants with chlorophyll chimera was more in the radiation treatments. Flower production was not sufficient to draw valid conclusions. In the VM2 generation, plant height exhibited a negative shift. Tiller, leaf and rhizome production, at the lower doses of the mutagens in general, exhibited positive shifts and at the higher doses, negative shifts. Wide range of variability was observed with respect to these characters. Pollen fertility was not seen influenced by the treatments. Screening the VM2 plants against bacterial wilt and soft rot diseases did not enable the isolation of tolerant/resistant material. Study of the mutant in the VM3 revealed that majority of the plants failed to express all or some of the characters. A few plants with more yield and dryage, and more volatile oil and NVEE content, were located. The studies indicated that though the range of variability induced is high, recovery of the mutants is very low; probably due to the multicellular nature of the apices of the rhizomes treated, and the consequent chimera formation and diplontic selection. Follow up of the mutation generation up to VM4 or VM5 or till stability is achieved and avoiding storage of the rhizomes between the generations have been considered necessary. Repeated, intensive and large scale induction and continuous screening for disease resistance is worth attempting. Using in vivo and in vitro adventitious bud techniques, somaclonal variation, in vitro screening for disease resistance, induction of mutation immediately after the harvest when buds are in ontogenetically young stage of development, and raising of VM2 and subsequent generations without storage of seed rhizome irrespective of the season, are areas suggested for future research.
Influence of explant source on the in vitro propagation of jack (Artocarpus heterophyllus Lam.)
(Kerala Agricultural University, 1985) Rajmohan, K; Mohanakumaran, N
Physiological ago of the explants exhibited significant influence on the in vitro propagation of jack. Shoot apices from the seedlings registered a multiplication rateof17.4x, with 100 percent rooting and 6.0 roots formed in 20.75 days. Explarits from fresh stem-sprouts of five, ten and thirty-year old trees recorded shoot multiplication rates of 4.50x, 2.80x and 2.09x, respectively in five weeks. The corresponding rooting percentages were 70 (with 5.43 roots formed in 13.43 days), 40 (with 2.59 roots formed in 24 days) and 15 (with 1.0 root formed in 46.7 days) after two to three subcultures. Explants from six-month old jack grafts failed to produce multiple shoots; but exhibited 50 per cent rooting with 2.0 roots formed in 20.5 days.
Intraclonal variations and nutritional studies in banana cv. Palayankodan
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1985) Rajeevan, P K; Mohanakumaran, N
The investigations were carried out at the Banana Research Station, Kannara, during 1981-84 in the banana cv. 'Palayankodan'. Twenty four accessions were subjected to detailed analysis with respect to growth, yield and quality. The plants of the accessions differed significantly with regard to height and girth of pseudostem during the later stages of growth , both in the plant crop and in ratoon 1. Significant differences observed in the number of functional leaves were not consistent. Area of the third leaf at shooting varied significantly in all the three crops. The trend in variation between the crops, however, was not consistent. Interval of leaf production, total number of leaves produced and the density of stomata in the upper surface of the leaf lamina showed significant differences. The duration from planting to shooting in ratoon 1 alone varied significantly. The plant crop took more time than ratoon 1 and ratoon 2 to come to harvest. The content of nutrient elements in the index leaf did not exhibit significant variations. The reactionof the accessions to the important pest (rhizome weevil) and diseases (bunchytop and Sigatoke) varied considerably.
Marathakam, a high yielding guineagrass clone
(Kerala Agricultural University, 1994) Sreekumar, S G; Gopimony, R; Gopinathan Nair, V; Mohanakumaran, N
Initial evaluation trials were conducted with ten mutant clones during 1983-84. Six promising clones selected on the basis of green fodder yield were advanced to CYT during 1984 to 1986 (3 years) along with FR 600 and Mackuenii as checks. Two promising clones MC 14 anil MC 16 selected on the basis of green and dry fodder yield were advanced to farm trials along with FR 600 Mackuenii, Haritha and . local check at 11 locations in Trivandrum district during 1990 and 1991. The clone MC 16 which had high green fodder yield and bettr fodder quality was recommended for release as 'Marathakam' suitable for cultivation in the uplands of Trivandrum district.
National agricultural research project in Kerala
(Kerala Agricultural University, Vellanikkara, 1995) Mohanakumaran, N
Performance of selected orchids under varying light regimes, culture methods and nutrition
(Department of Horticulture, College of Agriculture, Vellayani, 1996) Sabina George Thekkayam; Mohanakumaran, N
The present study was undertaken to evolve agrotechniques for cut flower orchid production in Kerala. Two experiments were conducted at the College of Agriculture, Vellayani in 1991 and 1992 with two popular cut flower varieties namely Arachnis Maggie Oei ‘Red Ribbon’ and Dendrobium Sonia – 16. The effects of varying light intensities and nutrient regimes under two methods of cultivation were assessed in Arachnis Maggie Oei ‘Red Ribbon’ (Experiment 1) and in Dendrobium Sonia -16, the performance under varying light intensities and nutrient regimes was evaluated (Experiment 2) In Arachnis Maggie Oei ‘Red Ribbon’, trench culture was found to promote growth, flowering and the floral attributes. The number of leaves, aerial roots, leaf area and plant height were greater in the trench grown plants. The number of inflorescences produced, their branching, length and vase life were also enhanced under trench culture. The effect of light intensities on growth was mediated through interactions with culture methods and nutrients. The trench grown plants under 50 and 75 percent light had a greater number of leaves and leaf area. The plants receiving 500 ppm of P and K under 100 percent light had a shorter stature. The direct effect and interactions of nutrients on growth were observed at certain months during the experimental period which was indicative of differences in the requirement at different stages of growth. The dry matter content of the stem and apical shoot was greater in the plants receiving 500 ppm P. Inflorescence production and the vase life of inflorescences was greater under 100 and 75 percent light. Branching of inflorescences was greater under 75 percent light. In Dendrobium Sonia -16 the number of inflorescences produced was greatest under 75 percent light. The length of the inflorescences was greater under 75 percent light and the span area of the flowers was greater under 50 and 75 percent light. Nitrogen at 500 ppm increased the length of the inflorescences, the number of flowers in an inflorescence, and the span area of the flowers. The number of inflorescences produced was also greater in the plants receiving 400 or 500 ppm N, 400 or 500 ppm K and in those receiving 500 ppm P. Interactions between the nutrients and between light intensities and the nutrients were also observed. The nutrient composition of the leaves in both the cultivars were enhanced by the 400 and 500 ppm doses of N and P and 500ppm K. Based on the observed effects, in Arachnis Maggie Oei ‘Red Ribbon’, trench culture of plants under 75 to 100 percent light and a nutrient dosage of 300 ppm N, 400 ppm P and 300 ppm K from planting till nine MAP and thereafter a dosage of 400 to 500 ppm N, 400ppm, P and 500 ppm K can be recommended. In Dendrobium Sonia -16 growing in pots under 75 percent light with 400 to 500 ppm of N, P and K can be recommended
Physiological investigations in relation to flowering, fruit set and capsule developmentj of cardamom (elettaria cardamomum maton)
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1986) Vasantha Kumar, K; Mohanakumaran, N
Investigations were carried out at the Cardamom Research Station, Pampadumpara and at the College of Horticulture, Vellanikkara during 1982 – ’84 to gather information on the physiological factors governing flowering, fruit set and capsule development of the three popular cardamom cultivars, Malabar, Mysore and Vazhukka. Emphasis had been given to unravel the causes of fruit (Capsule) shedding so as to evolve methods of control. Studies on growth and development in a broad sense depicted that an individual tiller of cardamom had a biennial growth habit. The different aspects of flowering and fruit set studied. Indicated that the variability was high in the Vazhukka cultivar and low in the Mysore cultivar. An early crop bearing habit was exhibited by Malabar, whereas Mysore possessed a late bearing habit and Vazhukka exhibited varying trends. The percentage of fruit set was high in Vazhukka, followed by Malabar and Mysore. Influence of climatic components on the physiology of flowering showed that a distinct dry spell triggered the panicle initiation process. The onset of rain coupled with high temperature was congenial for flower opening. A high soil moisture status combined with a high status of relative humidity (which resulted from a well distributed rainfall) enhanced the setting of capsules. Histological studies conducted in the genotype PV-1 (Malabar) showed that differentiation of panicle primordial was more during November to March. A prominent vascular zonation was observed in the rhizome nodes prior to the initiation of panicle promordia. Histology of the seeds revealed the development of starch grains at the greenish- yellow seed stage. Biological assays for endogenous auxins, inhibitors and cytokinins in the developing capsules indicated a spurt in auxin and cytokinin activity preparatory to fruit set. The level of inhibitory substances rose after the fruit set stage, while that of auxins fell which favoured the formation of an abscission zone causing shedding of immature capsules. Exogenous application of NAA (40 ppm) and 2, 4-D (4 ppm) increased the plant height, enhanced the production of panicles and flowers, reduced dropping of immature capsules and increased the yield. The uptake of nutrients revealed that cardamom is a heavy feeder of potash. The Vazhukka and Malabar cultivars developed less nutrients than the Mysore cultivar for producing unit yield of capsules. Radiotracer studies showed that the photosynthetic efficiency of cardamom was more under low light intensities. The rhizome was found to be the main sink in a cardamom tiller. Gas chromatographic estimation of cardamom oils indicated that the Mysore genotype (PR-107) was superior in quality aspects (because of high content of the esters, alpha terpenyl acetate, geranyl acetate and linalyl acetate) when compared with the Vazhukka genotype (PV-5) and Malabar genotype (PV-1). For consumption as a spice as well as for distillation of the essential oils, the black seed stages (‘karimkai’) was the most idel stage in cardamom.