Browsing by Author "Sudhakara, K"

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Bamboo (Dendrocalamus strictus (Roxb.) Nees) based agroforestry system: planting density effects on biomass accumulation, carbon sequestration, root distribution pattern and understorey crop productivity
(Department of silviculture and agroforestry, College of forestry, Vellanikkara, 2014) Bhimappa Kittur; Sudhakara, K
Bamboos: emerging carbon sink for global climate change mitigation
(2015) Sudhakara, K; Jijeesh, C M
Comparative performance of lesser yam
(Kerala Agricultural University, 1982) Ashokan, P K; Neelakantan Potty, N; Sudhakara, K
Conservation strategy for Hopea parviflora Bedd. species through storage of seeds using cryopreservation techniques
(Department of Silviculture and Agroforestry, College of Forestry,Vellanikkara, 2001) Ani, J R; Sudhakara, K
A detailed study was conducted at College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1998-2000 to standardize the conservation strategy for Hopea parviflora Bedd. species through storage of seeds using cryopreservation. Diameter of seeds collected at seven weeks after anthesis was found to be higher than that at sixth week. Physiological maturity of the propagules is attained between five and six weeks after anthesis. The propagules were subjected to different relative humidities, vacuum and dry air for different durations as a pretreatment for cryopreservation studies. In 100 to 46.6 per cent relative humidities, the moisture content and the leachate conductivity of the propagules were found to increase with duration compared to the initial value. Equilibrium moisture content of Hopea parviflora propagules was found to lie between 75.6 to 30 per cent relative humidities. Germination parameters of seed and seed without seed coat were not decreased significantly due to desiccation by relative humidities, vacuum or dry air, but that of embryonic axes was considerably reduced as rapid drying might have been effected due to 30 and 20 per cent relative humidities and also due to vacuum and dry air with duration. High culture contamination was observed in vacuum and dry air treatments. After cryopreservation techniques, the propagules invariably failed to regenerate but could retain green colour for two to three days.
Development of storage techniques for thampakam (Hopea parviflora Bedd.) seeds
(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2002) Shaji, M; Sudhakara, K
A detailed study was conducted at College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1999-2001 to develop a suitable storage technique for the seeds of Hopea parviflora Bedd. species through synthetic seed and cryopreservation technology. Moisture content of intact seeds/ seeds without seed coat/: excised embryonic axes decreased with increase in intensity and duration of desiccation levels and only the seeds without seed coat showed significant difference in moisture content due to maturity levels. Leachate conductivity was not significantly affected due to maturity levels of intact seeds and excised embryonic axes. But seeds without seed coat showed significant difference in leachate conductivity due to maturity levels and it was higher at seven weeks after anthesis. Increasing the duration of desiccation significantly increased the leachate conductivity of intact seeds/ seeds without seed coat! embryonic axes. Germination parameters of intact seeds and seeds without seed coat were not affected significantly by increased desiccation. However, excised embryonic axes showed significant difference in germination parameters when the intensity and duration of desiccation was increased. The synthetic seeds developed from these desiccated axes also showed significant difference in their germination parameters. Synthetic seeds stored at 4°C retained maximum viability after four weeks, compared to those stored at 200 C and 27 0 C. When stored at 27 0 C, the synthetic seeds developed from six weeks mature embryos retained viability up to three weeks whereas those at seven weeks after anthesis retained viability up to two weeks only. After cryopreservation, the propagules invariably failed to regenerate but could retain green colour for two to three days.
Dissolution rate of urea and muriate of potash packed in perforated polybags
(Kerala Agricultural University, 1985) Asokan, P K; Vikraman Nair, R; Sudhakara, K
Effect of seed size on the germination and seedling performance of teak (Tectona grantis Linn. f.)
(Department of Silviculture & Agroforestry, College of Forestry, Vellanikkara, 2004) Jijeesh, C M; Sudhakara, K
A detailed study was conducted at the College of Forestry, Vellanikkara to investigate the effect of seed size on seed characters and germination vigour and the effect of seed size and time of germination on seedling performance of teak (Tectona grandis Linn.f.) during 2001-2003. Most of the fruits were belonging the grades between 9 to 18 mm. 12-15 mm size grade recorded the highest proportion by number as well as the weight per kg of the sample lot compared to 15-18 mm, 9-12 mm and 6-9 mm grades. Size, volume and weight of the individual seeds not differed between the plantations studied. The average emptiness value of the seeds decreased with the increase in seed size. The number of empty, one, two, three and four 'true seeded' seeds increased with increase in seed size grade. The crude oil content of the true seeds ranged between 42 to 33 per cent by weight and that of soluble and total carbohydrate content ranged from 6.42 to 5.12 and 10.72 to 9.61 per cent by weight and these were found to increase with increase in size grade. The insoluble carbohydrate content of 'true seeds' was ranging from 4.5 to 3.8 per cent by weight and it varied significantly between the plantations and Cherupuzha plantation recorded the maximum amount. Protein content of the seeds ranged from 3.7 to 3.6 per cent by weight and it did not vary significantly between the plantations as well as size grades. Poly acrylamide gel electrophoresis of proteins at ph 7 gave similar banding pattern (two bands with Rm values 0.09 and 0.19) for different size grades in all the plantations. Storage of the seeds for one year significantly reduced the germination Size grade of the seeds used to conduct the nursery studies significantly influenced the germination percentage of the seeds as well as the vigour index of the seedlings. The effect of seed size grade and time of germination on seedling characters was significant at all stages of growth of the seedlings with the exception of taproot length, specific leaf area and chlorophyll a content of the seedlings. The seedlings belonging to 15-18 mm grade seeds recorded largest height, collar diameter, internodal length, length of longest lateral roots, leaf area, number of lateral roots, stem dry weight and chlorophyll b and total chlorophyll content at different stages of growth. Seedlings belonging to 9-12 mm seed grade recorded the lowest values of these characters. The leaf, stem and total dry weight of the seedlings at 270 and 360 DAP were found to increase with the increase in size grade of the seeds. Seedlings belonging to 9-12 mm grade showed higher RGR and NAR values compared to that of the seedlings belonging to 15-18 mm and 9-12 mm seed grades in first to fourth week germinants. There was no definite pattern in variation of number of leaves, and root:shoot ratio among the of the seedlings due to size grade of the seeds. With regards to time of germination of the seeds, seedlings obtained from the first week germinants recorded the largest height, internodal length, collar diameter and leaf area at all the stages of growth. Other characters did not show any definite trend due to time of germination. Significant differences due to seed size was absent in all the attributes related to the growth potential of the stumps prepared from 180 days old seedlings. However, the effect of time of germination of the stumps was significant in the number of lateral and tertiary roots per stump and length of the first, second and third longest lateral root. Dry weight of the lateral roots was found to increase with the increase in seed size grade of the stumps obtained from 360 days old seedlings. With regards to time of germination, the stumps obtained from the first to fourth week germinants varied significantly in the number of sprout, length of the second sprout, number of leaves, lateral and tertiary roots per stump and length of the first, second and third longest lateral roots.
Evaluation of seed source variation in Strychnos nux-vomica L. (Kanjiram) from different forest types of Kerala
(Department of silviculture and agroforesty, College of forestry, Vellanikkara, 2012) Shine, G; Sudhakara, K
Nutrient deficiency diagnosis in tectona grandis
(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1996) Jayamadhavan, A; Sudhakara, K
The foliar nutrient concentration of ten year old Teak plants collected from the Nilambur Teak plantation were analysed to standardize the canopy height, time of sampling, leaf rank and diameter class during the period 1992 – 94. Also, the leaf samples from the standardised position and time interval were analysed for a period of thirteen months starting from August, 1993 to August 1994 to study the variation in the foliar N, P and K concentration with season. Further, leaf samples from four different site qualities viz., site quality 1, 11,111 and 1V were analysed to determine the critical nutrient level. The chemical analysis of the leaf samples were carried out in the College of Forestry, Kerala Agricultural university, Vellanikkara. Since mean nutrient concentration was high and varied little among the samples, leaves taken from the bottom position of the crown during the time interval 9.am. to 11 a.m. were taken as the standard. Similarly, the second leaf rank from the tip and the fourth diameter class which was the largest, (16.75 cm – 20 cm) were found to be ideal for sampling. The foliar nutrient concentration were higher during the period starting from June to September, which received high rainfall and were low during the drier months of January, February, March and April. Equations were developed to predict the yield based on foliar nutrient concentration. A simple linear model of the form Y = B * X + A was used to predict the yield in terms of basal area or volume and the foliar nutrient concentration; where Y = basal area (m2) or volume (m3), X = foliar nutrient concentration and A and B are constants. But a higher predictability was obtained for the relationship between basal area or volume and foliar nitrogen, phosphorus and potassium concentration, when fitted with super geometrical model, Couchy model and parabolic model respectively. The super geometrical model used for the relationship between basal area or volume and foliar nitrogen concentration was of the form
Phenology and regeneration of shola-grassland edge tree species
(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2003) Nanaya, K M; Sudhakara, K
A study was undertaken in Mangaladevi, Periyar Tiger Reserve, and College of Forestry, Kerala Agricultural University, Vellanikkara, during the period 2001-2002 keeping in mind that edge species are better suited for the afforestation of the depleting shola forest than going for exotic species or any of the interior species. The specific objectives of this research project were to study and find out important edge tree species in the shola forest, to study the phenological aspects of these selected edge tree species and to study the artificial regeneration possibilities of these selected edge tree species. Phytosociological analysis revealed 47 species of trees along the shola- grassland edge in an area of 5950m2 across 27 families. Species with highest Relative Importance Value Index (RIVI) were Psychotria elongata (15.22). Ligustrum robustum (11.33), Maesa indica (10.53), Litsea wightiana (7.39), and Vernonia arborea (5.27). The total density of the Shola forest edge was 1703 individuals ha-1. Psychotria elongata had the highest density of 588 individual ha-1 followed by Maesa indica, Ligustrum robustum and Litsea wightiana which were subjected to further phenological observations to determine their phenological patterns. Leaf, flower and fruit phenological patterns followed by these selected edge tree species during the period between July 2001 and June 2002 have been presented in detail. Data obtained from the phytosociological analysis were used to derive various diversity indices of the arborescent flora of these forests have also been presented. Results of maturity, storage and artificial regeneration studies conducted on Psychotria elongata, Ligustrum robustum and Maesa indica have also been presented. Maturity studies reveal that the seeds of Psychotria elongata and Ligustrum robustum mature in the month of January while, the seeds of Maesa indica was mature during the months of September to January. Results of storage studies on these species suggest that storage of Ligustrum robustum and Psychotria elongata is not advisable while, storage of Maesa indica is beneficial as it shows a ripening period after collection. The study revealed the lower diversity along the edges of the shola forests of Mangaladevi. This is of great concern and immediate steps need to be taken to stop further degradation of these forests and rejuvenate them. The results available about the phenology, maturity and storage studies of these species can help in further studies, which can lead to use of native edge tree species for enrichment of these depleting forests.
Soil-plant nutritional status of Tectona grandis L.f. in relation to age and site quality
(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1999) Vimal, M; Sudhakara, K
Viability of hopea parviffora seeds with reference to temperature , medium of storage and microencapsulation techniques
(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1996) Sunilkumar, K K; Sudhakara, K
A detailed study was conducted at College of Forestry, Kerala Agricultural university, Vellanikkara, Thrissur, Kerala during 1994 – 95 to study the effect of temperature, storage medium, fungicide and microencapsulation of zygotic embryo (synthetic seed) on the storage behaviour of Hopea parviflora seeds. Storing the dewinged seeds with a moisture content below 30 per cent resulted in rapid decline in seed viability due to dehydration injuries irrespective of storage temperature. Sand and neemcake was inappropriate as a storage medium because sand favoured early germination of the seeds in storage condition itself and neemcake caused severe desiccation injuries. Storing fungicide treated winged seeds collected just before natural seedsheding, at 100 C retained high germination percentage upto 40 days. Sythetic seeds were also successfully stored up to 1 month at 100C without significant reduction in germination percentage. Two ppm and three ppm ABA was observed to be helpful for maintaining higher germination percentage of synthetic seeds during storage.
Weed control in rice under semi-dry system
(Kerala Agricultural University, 1986) Sudhakara, K; Nair, R R