PhD Thesis

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    Agro- techniques for sesame (Sesamum indicum L.) under partial shade of coconut in southern laterites
    (Department of Agronomy, College of Agriculture, Vellayani, 2024-10-19) Arunima Babu, C S.; Sheeja, K Raj
    The study entitled ‘Agro-techniques for sesame (Sesamum indicum L.) under partial shade of coconut in Southern Laterites’ was undertaken at College of Agriculture, Vellayani during 2021-24, with the objectives to standardize the nutrient levels for sesame under partial shade of coconut in Southern Laterites, assess the response of promising sesame varieties to the identified optimum nutrient levels and evaluate the allelopathic effect of sesame on selected weeds and crops. Field experiments were conducted at Coconut Research Station (CRS), Balaramapuram, to identify the optimum nutrient levels for sesame in Southern Laterites during Rabi 2021-22 and 2022-23, using variety Thilak. The experiments were conducted in the inter row spaces of coconut palms aged more than 60 years planted at a spacing of 7.6 m × 7.6 m. It was laid out in central composite design (CCD), with 20 runs viz., T1:31:20:16 kg NPK ha-1, T2:64:20:16 kg NPK ha-1, T3:31:50:16 kg NPK ha-1, T4:64:50:16 kg NPK ha-1,T5:31:20:34 kg NPK ha-1, T6:64:20:34 kg NPK ha-1, T7:31:50:34 kg NPK ha-1, T8:64:50:34 kg NPK ha-1, T9:20:35:25 kg NPK ha- 1, T10:75:35:25 kg NPK ha-1, T11:48:10:25 kg NPK ha-1, T12:48:60:25 kg NPK ha-1, T13:48:35:10 kg NPK ha-1,T14:48:35:40 kg NPK ha-1 and T15 to T20 (represented the central points of CCD): 48:35:25 kg NPK ha-1, replicated thrice. The nutrient level for sesame in Southern Laterites was standardized by plotting response surface curves using the seed yield of sesame during both years. Remaining observations were statistically analysed using randomized block design (RBD) with fifteen treatments (T1-T14, same as that of CCD, T15: was taken as the average of treatments T15-T20 in CCD). The growth parameters viz., plant height, number of leaves per plant, number of branches per plant and dry matter production were significantly influenced by different nutrient levels. Results on growth attributes at harvest revealed that, T1 produced taller plants during 2021-22 and 2022-23. However, T1 was on par with T2 during 2021-22 and with T2 and T4 during 2022-23. During both years, the highest number of leaves per plant was observed in T1 at 60 DAS. However, T1 resulted in more number of branches per plant at harvest during 2021- 22 and was on par with T2. While, during 2022-23, T2 produced more number of branches per plant and was on par with T1. During both years, DMP was significantly higher in T1 at all stages of observation. Physiological parameters were also significantly influenced by nutrient levels. During both years at 60 DAS, T1 resulted in higher LAI. However, it was on par with T2 and T4, during 2021-22 and with T2 during 2022-23. Chlorophyll content at 60 DAS was significant only during 2021-22 and T2 resulted in higher chlorophyll content which was on par with T1 and T4. Crop growth rate varied significantly with nutrient levels. At 40 DAS-60 DAS, T1 resulted in higher CGR which was on par with T2, T4 and T7 during both years. Similarly, higher RGR was noted in T1 which was on par with T2, T4, T7 and T11 at 40 DAS-60 DAS. Greater number of seeds per capsule was observed in T1 which was on par with T2 during 2021-22 and with T2 and T4 during 2022-23. During both years, the highest number of capsules per plant (57.7 and 74.7, respectively) and seed yield (503.5 kg ha-1 and 554.7 kg ha-1, respectively) were observed in T1. Pooled analysis of seed yield also revealed the highest value in T1 (529.1 kg ha-1). Whereas, the haulm yield and harvest index in T1 and T2 were comparable during both years. The optimum NPK levels identified by plotting the response surface curves during 2021-22 were 35:26:7 kg NPK ha-1 and 34:21:3 kg NPK ha-1 and during 2022-23 was 34:35:3 kg NPK ha-1. Oil content in seed varied significantly only during 2021-22 with the treatment T1 resulting in significantly higher oil content. During 2021-22, higher crude protein content was observed in T1 which was on par with T2. While during 2022-23, T2 resulted in higher crude protein content which was on par with T1 and T4. Higher P, Mg and Fe content in the seeds were observed in T2 during both years. Calcium content in the seeds was significant only during 2022-23 and was higher in T1. Similarly, Zinc content in the seeds was significant only during 2021-22 and was higher in T1. Post experiment soil analysis revealed that T1 resulted in higher organic carbon content, available N and P in the soil during both years. Available K was higher in T1 during 2021-22 and in T2 during 2022-23. The N, P and K uptake by the crop were also significantly influenced by nutrient levels and were higher in T1. The results on economics of cultivation revealed the highest gross return, net return and B:C ratio in T1 during both years. Field experiment to validate the response of promising sesame varieties to the identified optimum nutrient levels was laid out in split plot design during 2023- 24 at CRS Balaramapuram. The main plot treatments included five nutrient levels viz., 35:26:7 kg NPK ha-1 (n1), 34:21:3 kg NPK ha-1 (n2), 34:35:3 kg NPK ha-1 (n3), 31:20:16 kg NPK ha-1 (n4) and 30:15:30 kg NPK ha-1 (n5) and the sub plot treatments comprised of six sesame varieties viz., Kayamkulam 1(v1), Thilathara (v2), Thilarani (v3), Thilak (v4), GT 10 (v5) and TMV 7(v6). The nutrient levels had significant influence on growth parameters. Among the nutrient levels, n2 produced the tallest plants at harvest. Similarly at 60 DAS, number of leaves and branches per plant were higher in n2. At harvest significantly higher DMP was observed in n2. Similarly at 60 DAS, n2 resulted in higher LAI and chlorophyll content which was on par with n1. At 60 DAS-harvest, n2 resulted in the highest CGR and RGR. Significantly more number of capsules per plant, seeds per capsule and higher seed yield were observed in n2. Higher haulm yield was also observed in n2 which was on par with n1. Among the quality parameters, higher P, Ca, Mg, Fe and Zn content in the seeds were observed in n2. Similarly, higher N, P and K uptake and available N, P and K in the soil were observed in n2. The results on economics of cultivation revealed that the highest gross return, net return and B:C ratio were observed in n2. Adoption of optimum nutrient level (34:21:3 kg NPK ha-1) reduced the consumption of K by 90 per cent, compared to KAU POP recommendation, which could be attributed to medium to high K status in the soil of Southern Laterites. The growth parameters varied among the tested sesame varieties. Among the varieties, the tallest plants were observed in v5 at harvest. At 60 DAS, greater number of leaves and branches per plant were recorded in v5 which was on par with v4. At harvest, the highest DMP was observed in v5 (19.71 g per plant). Similarly, at 60 DAS, v5 had higher LAI which was on par with v4. The chlorophyll content was the highest in v5 at 60 DAS. Significantly more number of capsules per plant (84.0), higher seed yield (1066.0 kg ha-1) and haulm yield (2502 kg ha-1) were recorded in v5. The variety v5 recorded higher P, Ca, Mg and Fe content in the seeds. Results on nutrient uptake and availability revealed that higher soil available N, P and K in the post-harvest soil and N, P and K uptake by the crop were observed in v5.The variety GT 10 resulted in the highest gross return, net return and B:C ratio. Interaction effect of nutrient levels over varieties revealed that at 60 DAS and harvest, taller plants were observed in n2v5. The treatment, n2v5 also recorded more number of leaves per plant at 60 DAS. At harvest, the highest DMP was observed in n2v5. Higher LAI and chlorophyll content at 60 DAS were observed in n2v5. Similarly, n2v5 produced greater number of capsules per plant, higher seed yield ha-1and haulm yield ha-1. The results on nutrient uptake revealed that n2v5 resulted in higher N and P uptake. The treatment n2v5 also resulted in the highest gross return, net return and B:C ratio. The interaction effect of varieties over nutrient levels revealed that at harvest, all varieties except v3 produced taller plants at nutrient level n2. While v3 produced taller plants at n3. At 60 DAS, all varieties except v3, produced greater number of leaves per plant at n2. While, v3 produced higher number of leaves per plant at n3. At 60 DAS and harvest, all varieties produced higher DMP, LAI and chlorophyll content at n2. Similarly, all varieties produced the highest number of capsules per plant and seed yield ha-1 at n2. All varieties except v3 produced higher haulm yield ha-1 at n2. However, v3 produced higher haulm yield ha-1 at n1. The results on post experiment soil analysis revealed that all varieties except v1 recorded higher available N at n2. While, v1 recorded higher available N at n1. All varieties recorded the highest N and P uptake at nutrient level n2. The results on economics of cultivation revealed that all varieties recorded the highest gross return, net return and B:C ratio at n2. The leachates of different sesame varieties had significant impact on germination and seedling growth of weeds viz., Alternanthera sessilis, Setaria barbata and Cyperus rotundus. Leachate of variety GT10 had significant inhibitory effect on the germination, seedling shoot length, root length, dry weight, SVI I and SVI II of all tested weeds. Similarly, the leachates of different sesame varieties had significant impact on germination and seedling growth of tested crops viz., cowpea and okra. Application of leachate of variety GT 10 resulted in the lowest germination percentage, seedling shoot length, root length, fresh weight, dry weight, SVI I and SVI II of cowpea and okra. While leachates had no significant effect on the germination and seedling growth of amaranthus. From the results of the study, it could be concluded that the optimum nutrient level for sesame under partial shade of coconut in Southern Laterites was 34:21:3 kg NPK ha-1. Among the tested sesame varieties, GT 10 was identified as the best variety for Southern Laterites. The variety GT 10 raised under partial shade of coconut gardens manured with 5 t ha-1 of FYM + 34:21:3 kg NPK ha-1 (full dose of P, K and 75 per cent N as basal application and 25 per cent N as foliar spray at 3 per cent concentration, 30 DAS) realized the highest seed yield, net return and B:C ratio. Application of leachate of variety GT 10 had significant inhibitory effect on the germination and growth of test weeds (Alternanthera sessilis, Setaria barbata and Cyperus rotundus) and test crops (cowpea and okra).
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    Technological evaluation of kera ice cream
    (Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1996) Geevarghese, P I; Francis, U T
    An experiment was conducted to assess the suitability of incorporating coconut fat in the form of coconut cream in preparing ice cream and ice cream mix powder replacing milk fat at 25, 50, 75 and 100 per cent levels (treatments) so as to reduce the cost of preparation of ice cream. The product developed was named as kera ice cream and the qualities were compared with normal ice cream (control). Kera ice cream was prepared with pineapple flavour and a combination of sodium alginate and glyceryl monosterate as stabilizer since it was found to be the most suitable. It was found that replacement of milk fat with coconut fat at any level does not influence the acidity, pH and specific gravity of kera ice cream mix. The relative viscosity of kera ice cream was increased as fat substitution level increased. Higher surface tension was observed for the control, and among treatments it showed a gradual increase as replacement level increased. It was observed that the overrun percentage increased as replacement with coconut fat increased. Contrary to this a decreasing trend in meltdown time was observed as percentage replacement with coconut fat increased. Whipping ability was lowest for the control during the first 5 min of freezing but it significantly increased during the second five min of freezing. Structural details of the ice cream revealed that as replacement level increased the air cell diameter and cell wall thickness increased. Organoleptic quality of kera ice cream were comparable to normal ice cream. The savings in cost of production for kera ice cream with 100 per cent replacement was calculated as 40.57 per cent compared to control. The properties of the reconstituted ice cream revealed more or less similar trend in characters like acidity, pH, specific gravity, overrun, meltdown time and organoleptic properties as that of the freshly prepared ice cream. The ultra structure of the kera ice cream mix powder particle were studied and it revealed that as replacement level increased the particle size also increased. Clumping of the particles and irregular surface were more evident at 75 and 100 per cent level whereas particles of the control and 25 per cent had smooth surface. Solubility index of the powder increased as percentage replacement increased. Significant difference could be noted with regard to bulk density and percent volume occupied by the powder particle. Storage studies were conducted with different packaging material and metallised polyester polyethylene was found to be the best. The moisture and titratable acidity of kera ice cream mix powder with and without antioxidant were significantly higher at any replacement level at 180 days of storage. The thiobarbituric acid value showed a significant difference for the powder without antioxidant at 120 days of storage and with antioxidant the difference could be noted at 180 days of storage. Peroxide value was recorded as zero at different periods of storage upto 180 days of storage. At 180 days of storage, powder without BHA at any replacement level showed significant difference whereas in antioxidant added powder difference could be noted at 75 and 100 per cent replacement levels. Nutritional qualities of kera ice cream was evaluated by rat feeding trials and was found that protein efficiency value and feed efficiency were comparable to ice cream diet. The cholesterol and triglyceride level in animals fed with kera ice cream and ice cream were also not different. Pathological examination of carcases and tissues of animals under treatment and control groups did not reveal significant changes indicating that incorporation of coconut fat cannot cause any untoward effect in organs and tissues of animals. It can be concluded that coconut fat can be incorporated in the prepartation of ice cream and mix powder with out any noticeable changes in the quality. Addition of antioxidant prolongs the keeping quality of the powder by two months. There is no health hazard in consuming the kera ice cream as revealed by the pathological examination of tissues from the experimental animals fed with kera ice cream.
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    Dynamics and competitiveness of agricultural trade polices on coconut economy of Kerala
    (Department of Agricultural Economics, College of Horticulture, Vellanikkara, 2019) Thasnimol, F; Prema, A
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    Development of an integrated light (minimal) processing technology for tender coconut and tender coconut husk based products
    (Department of Processing Technology, College of Horticulture, Vellanikkara, 2004) Subramanian, K V; Raju, V K
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    Resource management for intercropping white yam (diocorea rotundata poir) in coconut garden
    (Department of Agronomy, College of Agriculture,vellayani, 2001) Suja, G; Muraleedharan Nair, V
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    Potassium supplying capacity of Neyattinkara- Vellayani soil association and its relationship with potash nutrition of major crops on them
    (Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1989) Valsaji, K; Subramonia Aiyer, R
    Detailed study on the potassium supplying capacity of Neyattinkara-Vellayani soil association and its relationship to potash nutrition of major crops on them namely coconut and cassava has been made. This soil association represents the red loam soil type and consists of Neyattinkara series tentatively classified under Typic Eutropepts and Vellayani series under Typic Tropudalfs. Soil samples were collected from selected fields under coconut and cassava for the dominant soil types namely sandy clay loam and sandy loam soils under Neyattinkara and Vellayani series. To find the most suitable depth and location of soil sampling for coconut samples were also drawn at two different depths of 0-30 and 30-60 cm from basins and interrows. Empirical methods, quantity intensity studies, electro ultrafiltration studies and foliar diagnostic techniques were employed to decide on the most suitable method for plant available K. The various intensity, quantity and capacity factors which relate the readily available, difficultly available and storage or buffer capacity were assessed for a proper appraisal of the K status and supplying capacity. The various soil K parameters such as total K, water soluble K, exchangeable K, available K, nonexchangeable K, HNO3 extractable K, H2SO4 extractable K, sodium tetraphenylboron extractable K and percentage K saturation were found to be low. The water soluable K formed higher proportion of available K than exchangeable K. Interrelations showed that water soluble K, exchangeable K and available K are in dynamic equilibrium. Nonexchangeable K did not show any relationship with available K indicating that it is a poor source of available K. Quantity-intensity studies showed that the shape of the Q/I curve was similar in all types of soil since they belong to a group of related soils. The Q/I parameters like Are.K, Ko, Kx. KL and potential buffering capacity values were low. The KL values were higher than NH4OAc.K. The free energy values were found to be high indicating easy release rates of K. For both coconut and cassava, the leaf K did not show any consistent relationship with the soil K parameters. Among the Q/I parameters, KL had significant relation with leaf K of coconut. EUF 10 and EUF 35 showed significant relationship with leaf K of both coconut and cassava. Electro-ultrafiltration studies showed that the easily desorbed K was more than the strongly desorbed K indicating easy supply rate. The EUF 30-35 values were related to HNO3.K showing that this fraction included some initially nonexchangeable K. EUF 10 had significant relation with exchangeable K and EUF 35 had significant relation with exchangeable and available K. The buffer parameters BK (EUF 10/EUF 30) and EUF.Q (EUF 30-35/EUF 30) values were low indicating low buffer capacity. The EUF desorption pattern showed that the first peak was within 10-20 minutes and prominent than the second peak. This indicated low reserve K but easy supply rates. The EUF desorption curve of soils with high NH4OAc.K was above that of soils with low NH4OAc.K. This indicated that with increase in NH4OAc.K the easily desorbed K also increased. The yield of coconut and cassava were related to the various K parameters to evaluate the suitability of different methods for available K. In most of the cases NH4OAc method was found to be suitable for both coconut and cassava. Leaf analysis was also found to be suitable. For cassava the result obtained after 41/2 months is meaningless for the current crop. For coconut collection of index leaf is laborious. It was also found that the Q/I and EUF were suitable for coconut. But these methods cannot be followed in routine soil testing because of the high input of laboratory work involved. Considering these aspects it was found that NH4OAc method is the most suitable one because it is simple, cheap and easy to adopt. Based on the NH4Ac.k content the fertility status was found to be low to medium. The various intensity, quantity and capacity factors of soil K, Q/I and EUF parameters revealed that this soil association has low K supplying capacity. Hence heavy dose of K fertilizers is required. Split application is preferable especially in sandy loam soils to reduce leaching losses. NH4OAc.K which was found as a suitable indicator of plant available K varied significantly in basin and inter-row samples of sandy clay loam soils. This K fraction did not vary with depth in both sites. In general, the K nutrient index indicated that the basin samples had a higher level than inter-row and surface samples. Thus basin sampling at 0-30 cm depth was found to be the ideal site of soil sampling for coconut tree.
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    Population dynamics, intensity of damage and management of the coreid bug, paradasynus rostratus dist.
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 2006) Ambily Paul; Nandakumar, C
    Experiments were conducted to study the influence of alternate hosts on the population dynamics of the coreid bug, Paradasynus rostratus Dist. and consequent damage to coconut and to evolve an eco-friendly management strategy to the pest. An abstract of the work done and the results are given below. A survey conducted in Thiruvananthapuram district to study the incidence and intensity of coreid bug infestation on coconut revealed that the infestation was the highest in the coastal region. The incidence was lower in the upland and midland regions. Among the variety of crops seen in the coconut based homesteads, guava, cashew, cocoa and neem were recorded as potential hosts of the pest. Studies on the influence of alternate hosts on the population build up of coreid bug revealed that the alternate hosts were a major determinant in the extent of infestation of coreid bug on coconut. The pest multiplied on the alternate hosts during flushing, flowering and fruit formation stages of the crops and subsequently shifted to the base crop, coconut in multiple cropping systems. The changes in size and yield parameters of nut due to the infestation of P.rostratus were assessed. Nuts with negligible damage (category II) did not show any significant difference in nut shape, nut characters, copra and oil content. Significant reduction in copra and oil was observed in moderately (category IV) and , heavily (category V) damaged nuts. The endosperm was not at all formed in severely damaged (category VI) nuts. The changes in the biochemical constituents of coconut buttons due to feeding of coreid bug were studied. The phenol content in young infested nuts recorded an increase compared to healthy nuts. A progressive reduction in starch and fibre content of young nuts was obtained with increase in degree of infestation The study on the effect of infestation of P.rostratus on germination and vigour of seedlings revealed that though all the nuts in damage category II (negligible damage) to IV (moderate damage) germinated within six months, only seedlings from nuts with negligible damage (category II) had the qualities of good seedlings. The antifeedant effect of neem based botanicals and efficacy of synthetic chemical pesticides were evaluated against coreid bug. Among the botanical and chemical pesticides, neem seed oil- garlic emulsion 2 per cent and profenophos 0.05 per cent proved most effective against the coreid bug. A field experiment was conducted to evaluate the effect of selected treatments on alternate hosts for control of coreid bug in coconut. The study revealed that the combined application of neem seed oil- garlic emulsion 2 per cent + profenophos 0.025 per cent was the most effective in reducing the extent of coreid bug infestation in the surrounding coconut palms. The present study could establish the role of alternate hosts on the population buildup of coreid bug. Plant protection operations in alternate hosts against coreid bug are more effective, economical and viable options compared to those in coconut. Based on the results of the study, a package involving regular monitoring of the alternate hosts in the homesteads, removal and destruction of the egg masses and early instars of the pest and giving a need based spray with an insecticide formulation like neem oil- garlic emulsion 2 per cent + profenophos 0.025 per cent on the alternate host would be a practical and cost effective approach for reducing the damage of P.rostratus on coconut in the homesteads.
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    Evaluation and characterisation of effective fungal pathogens associated with the coconut eriophyid mite (Aceria guerreronis Keifer)
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2006) Amritha, V S; Pahummal Beevi, S
    Outbreak of coconut eriophyid mite has become a serious menace by inflicting heavy damage to coconut plantation both in terms of yield reduction and economic return. The increased awareness of the general public about the repercussions of extensive use of chemical pesticides and also because of the apprehension being expressed by scientists and policy makers on various side effects of chemicals, biocontrol is getting more attention in the management of mite. The present study on “Evaluation and characterisation of effective fungal pathogens associated with coconut eriophyid mite (Aceria guerreronis Keifer)” was carried out in the Department of Agricultural Entomology, College of Horticulture, Vellanikkara. The main objectives of the study were to isolate, identify and confirm the pathogenicity of fungi associated with the eriophyid mite, identification of the potential acarifungal pathogens and molecular characterisation of the selected isolates. Survey conducted at three different locations each from four panchayaths of Thrissur district for one year revealed that there was no significant difference in mite population (live mite, dead mite and egg) among the four panchayaths, but it varied significantly within the three locations of the four panchayaths. A uniform distribution of mite population was followed in the outer perianth, inner perianth and nut surface with maximum live mites and egg count on the nut surface and dead mites on the inner perianth. Live mite and egg count contributed to about 36 per cent while the dead mite formed 28 per cent of the total mite population. Predatory mite population varied significantly both among the four panchayaths as well as among the locations within the four panchayaths. Two types of predatory mites, Amblyseius spp. and Bdella spp. were mainly observed during the study with an average population range from 4.469 to 15.719 per nut. Seasonal variation showed three peaks of live mite population and egg count during the late monsoon (August), winter (January/February) and summer (April/May) months; where as two peaks during winter (January to February) and summer (March to April) for the dead mite population. Predatory mite population followed a normal range which increased with increase in mite population to a certain degree within the limited range of predatory mite population. Correlation analysis showed a positive relationship between population parameters of mite (live mite, dead mite, egg count) and predatory mite population and maximum temperature. A non-uniform correlation was observed between mite population and other weather parameters. Natural occurrence of the mite specific pathogen, Hirsutella thompsonii isolates at monthly intervals for 12 months contributed to 4.90 per cent. Maximum number of Hirsutella isolates was obtained during winter season followed by the monsoon season. Isolates belonging to the genus Fusarium spp., Acremonium spp. and Paecilomyces spp. were mostly isolated during the monsoon season while the isolates of actinomycetes during summer period over the entire four panchayaths. The fungal species which proved pathogenicity to coconut eriophyid mite were two species coming under the genus Hirsutella, viz., H. thompsonii and H. kirchnerii and the other fungal species coming under the genus Acremonium viz., A. strictum and A. incoloratum, Fusarium viz., F. lateritium and F. verticillioides, Paecilomyces, P. fumosoroseus and P. lilacinus. Based on the presence or absence of synnemata, two different varieties of Hirsutella were found to occur, namely, H. thompsonii var. thompsonii and H. thompsonii var. synnematosa. Cultural and morphological observations revealed that among the eight isolates coming under the two varieties H. thompsonii var. synnematosa isolate, Madakkathara-I recorded maximal fungal growth (4.167 cm) and biomass (2.660 g) while the H. thompsonii var. thompsonii isolate, Chirakkekodu-I possessed maximum mean sporulation (3.33 x 106 spores ml-1). Among the other fungal pathogens, maximum growth and sporulation was observed on Acremonium spp., A. strictum (7.99 cm) and A. incoloratum with a mean value of 43.11 x 106 spores ml-1. Mortality assessment of the Hirsutella isolates along with other fungi at their respective doses of sporulation revealed that the fungal pathogen, P. fumosoroseus recorded the maximum mortality of 83.65 per cent which was closely followed by H. thompsonii var. thompsonii (Chirakkekodu-I) with a mortality of 80.63 per cent. Molecular characterisation of the seven isolates of Hirsutella using the five primers comprising of the OPE and OPAH series exhibited a maximum genetic similarity of 74 per cent between the Hirsutella isolates, Madakkathara-I and Konnakuzhy-I. Fifty per cent genetic similarity was obtained between two clusters with the Hirsutella isolate, Marakkal-I in one cluster and all the other Hirsutella isolates and H. kirchnerii in the other cluster. The isolates coming under two varieties of H. thompsonii, H. t. var. thompsonii, Chirakkekodu–I with maximum sporulation and H. t. var. synnematosa Madakkathara-I with maximum growth rate and biomass came under the same subcluster.
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    Extension strategies for the major farming systems in the context of the changing agricultural situations in kerala
    (Department Of Agricultural Extension, College Of Agriculture, Vellayani, 2004) Balachandranath, N G; Prakash, R
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    Production dynamics of ginger (zingiber officinale R.) under varying levels of shade, nutrients and triazole
    (Department of Horticulture, College of Agriculture, Vellayani, 1999) Ajith Kumar, K; Jayachandran, B K
    The experiments were conducted at the Coconut Research Station, Balaramapuram, during 1996-97 and 1997-98 to study the production dynamics of ginger under varying levels of shade, nutrients and triazole. The specific objectives were to study the production potential of ginger under open and different shade levels, to standardise optimum dose of nutrients and mulch for ginger intercropped in coconut garden and to evaluate the efficacy of triazole in the improvement of yield and other desirable characters. The effect of shade on growth and yield contributing parameters viz., tiller number, leaf number, leaf area, leaf dry weight, root spread, root volume, rhizome spread, rhizome thickness, number of rhizomes, leaf thickness, stomatal frequency, DMP and LAI under 20 and 40 per cent shade levels exhibited significant superiority in pot culture study. In pot culture study: maximum fresh ginger yield of 450.0 and 396.3 g plant" were resulted from plants kept under 20 and 40 per cent shade levels respectively. This was 27.4 and 12.2 per cent higher compared to open- condition. The dry ginger yield of 94.5 and 89.2 g plant" were obtained from plants kept under 20 and 40 per cent shade levels respectively. This was 27.8 and 20.7 per cent higher compared to open condition. However, the dry ginger yield obtained from 60 and 80 per cent shade levels were significantly lower compared to open. The shade levels 20 and 40 per cent gave the highest shoot dry weight of 48.9 and 53.6 g plant" respectively. Volatile oil content showed an increasing trend with increasing levels of shade in pot culture study. Maximum NVEE was recorded under 20 and 40 per cent shade levels. Highest starch content was obtained from 20 per cent shade level. Crude fibre gradually reduced with increase in shade levels. The field trial on nutrient requirement of ginger as intercrop in coconut garden revealed that, NPK application at higher levels increased plant height, tillering, leaf number, leaf area, DMP and chlorophyll content. Physiological parameters like, NAR, CGR and RGR were promoted by higher rates of nitrogen application. The results revealed that, N: P, N : K and P : K ratios of l.5 : 1, l.5 : 1 and 1 : 1 respectively, were ideal to get maximum fresh ginger yield. Application of 150 kg N, 100 kg P20S and 100 kg K20 ha-l gave maximum net profit ofRs. 96605/- and Rs. 99227/- during first and second year respectively. The net profit when the existing recommendation of 75 kg N, 50 kg P20S and 50 kg K20 ha-l was Rs. 54960/- and Rs. 54730/- during first and second year respectively. Hence the study suggests that the existing recommendation (75 kg N, 50 kg P20S and 50 kg K20 ha") has to be doubled (150 kg N, 100 kg P20S and 100 kg K20 ha-l) for increasing the productivity of ginger intercropped in coconut garden. Increased rate of fertilizer application did not influence the quality of the produce. Plant uptake of NPK increased with higher levels of fertilizer application. The field experiment on mulch requirement of ginger intercropped in coconut garden showed that the rhizome yield from plots mulched with 30.0, 22.5 and 1 =r. 0 t ha' were on par. Therefore the mulch requirement of ginger intercropped in coconut garden can be reduced from 30 t ha-l to 15.0 t ha-I Application of triazole did not exhibit any beneficial effect on yield and quality of ginger.