Browsing by Author "Geetha, D"

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Characterization and exploitation of jelly mushrooms (auricularia spp./ Tremella spp.)
(Department of Plant Pathology, College of Agriculture, Vellayani, 2017) Priya, R U; Geetha, D
Enzyme production and composting potential of oyster mushroom (Pleurotus spp.)
(Department of Plant Pathology, College of Agriculture, Vellayani, 1999) Owseph Ansu, P; Geetha, D
In the present study, solid state fermentation (SSF) of different substrates were carried out using Pleurotus spp. to evaluate the comparative efficiency of four Pleurotus spp. for their enzyme (cellulase and laccase) production potential and cellulose and lignin degrading ability .. The yield characteristics as well as reduction in height and weight caused by different Pleurotus spp. on paddy straw and coir pith (retted and non retted) were recorded. Samples drawn at 10, 20 and 30 days of SSF were subjected to chemical analysis for their enzyme (cellulase and laccase) production and cellulose and lignin reduction. The cellulose and lignin concentration of uninoculated substrates were also estimated. Paddy straw supported the maximum fruit body production whereas there was no sporophore production in retted coir pith. The highest yield was recorded by Vellayani P2 followed by P. djamor. The height and weight of all the substrates reduced significantly on S SF, the maximum reduction being recorded in paddy straw followed by that in non retted coir pith and retted coir pith. However no significant difference was observed in the reduction caused by the different Pleurotus spp. tested. The maximum cellulase production was recorded by P. sajo-caju on paddy straw on the 20th day of incubation. P. sajor-caju caused the highest level of cellulose degradation, the maximum percentage of degradation having occurred in retted coir pith on the 30th day of SSF. The highest recorded level of laccase production occurred in paddy straw on the so" day of incubation with Vellayani P2 isolate of Pleurotus. However, among the different Pleurotus tested P. sajor-caju recorded the maximum level of laccase production. The maximum percentage of lignin degradation was recorded by P. sajor-caju in retted coir pith on the so" day of SSF. Correlation worked out between cellulase production and cellulose degradation by different Pleurotus spp. was significant positive. However the positive correlation obtained between laccase production and lignin degradation by Pleurotus spp. was not significant.
Evaluation of biochemical and anti-cancerous activities of mushrooms
(Department of Plant Pathologoy, College of Agriculture vellayani, 2018) Agnes Jose; Geetha, D
Investigation on the edible species of Coprinus and standardisation of techniques for its large scale artificial cultivation
(Department of Plant Pathology, College of Agriculture, Vellayani, 1982) Geetha, D; Chandrasekharan Nair, M
A survey conducted in and around the college of Agriculture, Vellayani Campus revealed that the commonly occurring species of Coprinus were Coprinus lagopus (Fr.) Fr. C.disseiminatus (Pero. ex Fr.) S F Gray and C.ephemorus (Bull.ox Fr.) Fr. and among these, the most commonly occurring species was C.lsgopus. The culture of c.lagopus used for the present study was isolated from paddy straw beds of Volvarlella volvocea raised at the Department of plant Pathology and maintained on potato dextrose agar slants by subculturing periodically.
Leaf blight of eucalyptus citriodora hook
(Kerala Agricultural University, 1994) Wilson, K I; Geetha, D; Halm George
Physiological and cultural studies on blue oyster mushroom (Hypsizygus ulmarius (Bull.:Fr.) Readhead)
(Department of Plant Pathology, College of Agriculture, Vellayani, 2016) Sumi, I; Geetha, D
Strain improvement of oyster mushrooms- pleurotus cystidiosus O.K. Mill and pleurotus opuntiae (Durieu and LEV.) SACC.
(Department of Plant Pathology, College of Agriculture, Vellayani, 2018) Krishnapriya, P J; Geetha, D
The present study entitled “Strain improvement of oyster mushrooms: Pleurotus cystidiosus O.K.Mill and Pleurotus opuntiae (Durieu and Lev.) Sacc.” was carried out in College of Agriculture, Vellayani during 2015-2018, with the objective to standardize the techniques for production of oyster mushrooms: P. cystidiosus and P. opuntiae; and to study their morphological, physiological and cultural characteristics as well as nutritional and organoleptic qualities; and to undertake genetic improvement by protoplast fusion. The mushrooms were collected from two locations of Thiruvananthapuram and three fast growing isolates of Pleurotus spp. viz., PC2 (Vellayani), PNC1 (Chirayinkeezhu) and PO1 (Vellayani) were selected for the study. These isolates were identified as P. cystidiosus subsp. abalonus, P. cystidiosus and P. opuntiae using internal transcribed spacer (ITS) primers and subsequent sequencing; and registered at Genbank database with accession numbers KY214254, KY887023 and KY214255 respectively. The fast growing isolates of P. cystidiosus (coremial), P. cystidiosus (non-coremial) and P. opuntiae recorded maximum growth on PDPA amended with one per cent yeast under dark condition. The optimum temperatures for the growth were 30 0C, 25 to 30 0C and 25 0C respectively whereas, the optimum pH were 8, 8 and 7 to 8 respectively. Studies with different substrates and amendments for spawn production revealed that sorghum with one per cent yeast was the best for P. cystidiosus (coremial) and P. opuntiae whereas, paddy grains with one per cent yeast for P. cystidiosus (non-coremial). Experiments with different substrates and amendments for mushroom production revealed that rubber wood sawdust sprayed with 2.5 per cent of 1 M potassium dihydrogen phosphate recorded the maximum BE for P. cystidiosus (non-coremial) (192.76 per cent). P. opuntiae recorded the maximum BE in rubber wood sawdust amended either with 4 per cent neem cake (91.38 per cent) or wheat bran (91.37 per cent). Major insect pests observed in the beds of Pleurotus spp. were phorid flies, spring tails, black ants and staphylinid beetles. The competitor moulds observed were different species of Coprinus, Aspergillus, Penicillium and Trichoderma. Sporocarps soaked in one per cent CA for 15 minutes followed by mechanical drying and powdering was the best post harvest treatment for both P. cystidiosus (non-coremial) and P. opuntiae. Mycelium of P. cystidiosus (coremial) showed black coremial structures, representing its asexual stage (Antromycopsis broussonetiae Pat. & Trab.). The coremia comprised of elliptical (16.31 µm x 7.48 µm) and round conidia (8.06 to 8.49 µm). The black colour of coremia was due to melanin which was extracted (255.56 mg l-1) and characterized. The performance of long duration P. cystidiosus (non-coremial) and short duration P. opuntiae was compared with two ruling mushrooms of Kerala viz., long duration P. florida (Mont.) Singer and short duration P. eous (Berk.) Sacc. The study revealed that P. cystidiosus (non-coremial) and P. opuntiae showed higher BE compared to P. florida and P. eous, respectively. P. cystidiosus (non-coremial) recorded maximum moisture (94.05 per cent), starch (200.55 mg g-1), protein (30.2 mg g-1), fat (4.25 per cent), antioxidants (485.45 μg equivalent gram of ascorbic acid-1), beta-carotene (25.69 µg 100 mg-1), polyphenols (7.55 mg g-1) and energy (359.45 Kcal) compared to other Pleurotus spp. Sensory evaluation of mushroom products made from the species of Pleurotus was done and masala curry prepared from P. cystidiosus (non-coremial) scored the maximum value for overall acceptability. Shelf life of P. cystidiosus (non-coremial) was higher (5 days) compared to P. opuntiae, P. florida and P. eous (3 days each) in perforated poly propylene covers stored under refrigeration. Vanillin (0.05 per cent) and carbendazim (1 mM) were selected as dual biochemical markers for the PEG mediated protoplast fusion. Three days old P. cystidiosus (non-coremial) and four days old P. opuntiae recorded the maximum protoplast yield at five and four hours after incubation respectively with 0.6 M KCl and 30 mg ml-1 of enzyme consortium. Eight fusant lines with varied mycelial characters were obtained. Among fusants, F6 and F8 did not segregate in the second generation whereas, F4 segregated. F6 and F8 recorded higher BE of 168.05 and 99.95 per cent respectively compared to the parental lines and other fusants. Sporocarp of F6 and F8 was morphologically similar to P. cystidiosus (non-coremial) and P. opuntiae respectively; and F8 also exhibited low temperature adaptability. The present investigation indicated the exploitability of two promising isolates viz. P. opuntiae for tropical areas and P. cystidiosus (non-coremial) for cooler regions of Kerala using locally available materials and the standardized cultivation practices. The present study also standardized the protoplast fusion technique between P. cystidiosus (non-coremial) and P. opuntiae; and two fusant lines (F6 and F8) recorded higher BE which can be used for future breeding programmes.
Strain improvement of Pleurotus spp.
(Kerala Agricultural University, 1996) Geetha, D; Sivaprakasam, K
The effect of gamma irradiation, ultraviolet irradiation and nitroso-guanidine treatment of spore suspensions of three mushrooms viz., Pleurotus sajor-caju, P. citrinopileatus, P. djamor on the mycelial growth and yield performance was studied. Ultraviolet irradiation had no effect either on the mycelial growth or yield. Gamma irradiation at dose rate of 2000, 2500 and 3000 rad showed significantly increased mycelial growth and yield of Pleurotus spp. Treatment with nitroso-guanidine also resulted in increased mycelial growth, significantly higher yield and earliness in the appearance of sporophores.
Utilization of fungi for composting and mushroom production on coirpith
(Department of Plant Pathology, College of Agriculture, Vellayani, 2003) Sherin Salam, A; Geetha, D
The present study entitled "Utilization of fungi for composting and mushroom production on coirpith" was conducted during 2001 to 2003 at College of Agriculture, Vellayani, Thiruvananthapuram district with the objective to isolate most efficient fungi for degradation of coirpith and standardization of technology for mushroom production on coirpith. Four lignocellulolytic fungi viz., Aspergillus niger, A. ochraceous, Trichoderma harzianum and Rhizopus stolonifer were isolated from retted coirpith. Three mushrooms viz., Pycnoporus sanguine us, Ganoderma applanatum and Pleurotus tuber-regium collected during surveys conducted in different parts of Thiruvananthapuram district, and Lentinus edodes, Pleurotus florida and Calocybe indica were procured from TNAU and College of Agriculture, Vellayani. P. tuber-regium, a mushroom collected during the study is a new report from India. This edible mushroom has a biological efficiency of 46 per cent and is ideally suited for cultivation in Kerala. T. harzianum was the fastest colonizer on retted coirpith followed by G. applanatum and L. edodes. The maximum reduction of organic carbon, C:N ratio, cellulose and lignin and the maximum increase of nitrogen content in retted coirpith was recorded when it was degraded by T. harzianum, Among the different substrates used for mushroom production, the maximum yield of P. florida was realized in a substrate containing 1: 1 combination of retted coirpith and spent mushroom substrate while the maximum yield of C. indica was observed in a substrate containing 1:3 combination of non-retted coirpith and paddy straw. , Composted coirpith was found to be unsuitable as a substrate for large scale cultivation of oyster and milky mushrooms.