Browsing by Author "Krishnan, S"
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ArticleItem Open Access Combining ability analysis in cowpea (Vigna Unguiculata [L.] Walp)(Kerala Agricultural University, 1998) Sobha, P P; Abdul Vahab, M; Krishnan, S; KAUCombining ability was studied in a 10 x 10 diallel cross in cowpea for nine important characters. The variance due to general combining ability and specific combining ability showed both additive and non-additive gene action for plant height, primary branches, days to flowering, pod length, pod weight, pods per plant, seeds per pod, 100 seed weight and yield per plant. Among ten parental lines, Arka Garima, VU-18, Selection 2-1, Section 263, Pusa Komal and Kanakamoni were good general combiners for most of the yield components. The hybrids VU-18 x Arka Garima and Selection 2-1 x VS 389 possessed high specific combining ability effects for yield per plant.ArticleItem Open Access Comparison of two methods for the study of permanent manurial trials(Kerala Agricultural University, 1982) Krishnan, S; Surendran, P U; Gangadhara Menon, P K; KAUA rigorous justification for the comparison of treatments by the stability approach initated by Finlay and Wilkinson (1963) has been attempted. The data on Jaya variety of rice were analysed both by the method of stability co-efficients as also by the method of analysis of groups of experiments. The results obtained by the above two methods revealed that they are equalent.ArticleItem Open Access Estimation of distribution of cumulative rainfall for a specific period within a Njattuvela(Kerala Agricultural University, 1993) Krishnan, S; Narayanikutty, U; KAUA stochastic model for determination of time distribution of cumulative rainfall for a specific period within a njattuvela was worked out by making use of the daily rainfall data collected from the Regional Agricultural Research Station, Kerala Agricultural University, Kumarakom. A day having a minimum of 3 mm of rainfall was regarded as a wet day. The daily rainfall depth within a njattuvela was characterised using an exponential distribution. Further the first and second order Markov chain models were fitted to the data. Thechi-square test for adequacy of f i t revealed that the first order was the best fit. Using the first and second order Markov chain probabilities, the cumulative rainfall depth of at least a reasonable amount was worked out. The study thus brought out that the significance of stochastic models for characterisation of time, distribution of rainfall depth.ArticleItem Open Access Estimation of leaf area in garcinia cambogia (Kodampuli) through linear measurements(Kerala Agricultural University, 1996) Lila Mathew; Sarah T George; Krishnan, S; KAUThesisItem Open Access Exploratory analysis of permanent manurial trials in rice(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 2017) Suvarna Shyam, K T; KAU; Krishnan, SPermanent Manurial Trials are experiments performed at fixed sites in a long run to assess the role of nutrient sources in catalyzing crop production. The experimental data from Permanent Manurial Trial in rice at RARS, Pattambi was explored in a view to identify suitable set of fertilizer treatments in optimizing grain yield.The experiment was commenced in 1973 under Kerala Agricultural University State Plan Project and is being conducted continually over years in two cropping seasons viz., Kharif and Rabi. Eight fertilizer treatments under test were either organic, inorganic or combination thereof. As treatment responses can be deliberately measured through yield, grain yield data maintained at research station for the period 1973 to 2015 formed the basis of study. Treatment-wise rice yield data was subjected to various statistical analyses, to screen superior fertilizer treatments. The influence of weather on yield responses were also assessed. Exploratory Data Analysis using graphical and non-graphical methods as a means to familiarize yield data was attempted to realize yielding behavior of treatments. Summary statistics viz., mean and median explicitly showed the superiority of treatment T1 ( Cattle manure at 18000 kg ha -1 to supply 90 kg N ha-1) followed by treatment T5 (Cattle manure at 9000 kg ha-1+ ammonium sulphate to supply 45 kg N ha-1+ superphosphate to supply 45 kg P2O5 ha-1 +45 kg K2O ha-1 as muriate of potash). Box plot of yield data remarked consistent yielding performance for the same treatments during both Kharif and Rabi seasons. Yield trend was assessed by regressing crop yield on time factor and no significant yield trend was observed. Analysis of variance was done for each of the experiments during both seasons and the post hoc test was effected through DMRT. All the experimented seasons showed significant fertilizer effect on grain yield. The treatments subgroups as formed through DMRT for each year was further used to score treatments. Lowest scores speaking of better treatment performance was recorded for T1 in both the seasons followed by T5. Analysis of groups of experiments was further necessitated to generalize on the yielding behavior of each treatment as results followed from analysis of variance for individual experiments do not give a confirmatory account in this regard; owing to its inclusion of seasonal fluctuations (season/ year) in experimental error. The results showed superiority of treatment T1 and T5 during both seasons. Influence of weather on grain yield was studied for three growth stages of rice viz., early tillering to panicle initiation, panicle initiation to flowering and flowering to milk stage. The results followed from correlation and regression analysis pointed to minimal role of weather in affecting grain yield, attributed to the crop management practices followed in the research station. Regression models for treatment-wise yield on weather indices formulated through principal component analysis were found poor fit as observed through R2 value. Consistency of treatments were assessed through two consistency measures and treatments T1 and T5 were observed to have average consistency. Sustainability Yield Index (SYI) index was further used to identify treatments that have yielded in a sustainable manner in comparison with the maximum yield reckoned for each of the treatments over a longer period. Maximum SYI was recorded for treatments T1 followed by T5 during both seasons. Combinatorial treatments of organic and inorganic fertilizers had higher index values compared to purely inorganic treatments. Statistically optimum fertilizer requirement was obtained by compiling the results followed from the aforementioned analyses. Treatment T1 (Cattle manure at 18000 kg ha ammonium -1 to supply 90 kg N ha-1) and T5 (Cattle manure at 9000 kg ha-1+ sulphate to supply 45 kg N ha-1 + superphosphate to supply 45 kg P2O5 ha-1 + 45 kg K2O ha-1 as muriate of potash) were chosen as the optimal fertilizer schedules for rice.ThesisItem Open Access Formation and efficient estimation of stochastic frontier production functions(Department of Agricultural Statistics,College of Horticulture Vellanikkara, Thrissur-680 656, 2013) Dhanesh, N J; KAU; Krishnan, STechnological change and efficiency improvement are important sources of productivity growth in any economy. The concept of technical efficiency (TE) is based on input and output relationships. Technical inefficiency arises when actual or observed output from a given input mix is less than a possible mix. The analysis of technical efficiency involves the assessment of the degree to which the production technologies are utilized. The present investigation on “Formation and efficient estimation of stochastic frontier production functions” was carried out in the Department of Agricultural Statistics, College of Horticulture, Vellanikkara during 2010-13, to assess the present economics of pepper cultivation, to formulate new stochastic frontier production functions and to compare them. The secondary data collected from the Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara on area of holdings, number of vines, yield, expenses for machinary, labour, manure, and other expenses for the cultivation of pepper in the three blocks viz; Mananthavady, Kalpetta and Bathery were used for the analysis. The summary statistics revealed that irrespective of the blocks, the expenditure on labour was the highest followed by expenditure on manure and it was increasing according to the increase in age of plants. For the stochastic frontier production model to be realistic, exact measurement of the cost of the inputs as also the realized output is extremely necessary. Very few farmers keep records of the expenditure incurred on the various inputs and very rarely the output realized. Vegetable crops have a short duration. So the farmer will be in a position to give realistic figures regarding the various inputs as also the outputs. As regards plantation crops, there will be a lag right from establishment of the crop to the steady bearing stage. Therefore, it will be very difficult to trace back the exact cost, as no records would be available about the costs incurred. A rapid estimation survey is the only feasibility where in simultaneous estimation of the costs involved at from the nursery through the various stages of growth can be observed. Since a farmer who is already having a steady bearing crop, would have incurred lesser costs through the previous stages of growth of the crop, it is most feasible to use the concept of present worth to arrive at exact costs of previous stages of the crop. The stochastic frontier analysis was done using the present value (PV) as also with the present cost. The stochastic frontier analysis (SFA) was done for all the three blocks compounding all the costs starting from the nursery stage (First age group) up to the steady bearing stage (Fourth age group) using PV. The mean technical efficiency was observed to be 0.93, 0.91 and 0.94 for Mananthavady, Kalpetta and Bathery Blocks respectively. The stochastic frontier approach for each age group by pooling over the blocks, were also worked out using PV and it revealed a mean technical efficiency of 0.95 and 0.92 for the plantations in the third and fourth age groups respectively. To assess the factors influencing technical efficiency, the regression of TE on the factors like area of holdings, number of vines, cost for implements and machinary, labour, manure and other expenses was fitted for each block. About 91 per cent of the variation in technical efficiency could be explained using these variables. When the area of holdings increased, the technical efficiency seemed to decrease. With proper labour management, the technical efficiency can be significantly improved.ArticleItem Open Access Genetic variability in Abelmoschus Caillei L.(Kerala Agricultural University, 1999) Reena Susan Chacko; Suresh Babu, K V; Rajan, S; Krishnan, S; KAUStudios on parameters of variability . correlation and path coefficient analysis of fruit yield in Abttmoschus caillei L- revealed that characters such as number of branches per plant, number of nodes per plant, plant height and fnlit length had maximum coefficient of variation. Higher values of heritahility anil genetic advance were simultaneously estimated for fruit yield per plant and fruits per plant. Yield per plant had hiph positive significant correlation with fruits per plant, fruit length, fruit weight, plant height and number of intemodes on main stem. Path analysis revealed positive direct effect on fruit yield per plant through fruits per plant followed by plant height.ThesisItem Open Access Interaction effect under ammi model(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 2006) Eldho, Varghese; KAU; Krishnan, SThe study of interaction is one of the major objectives of most of agricultural experiments. Conceptually this is done based on regression technique. Among the interactions studied, two factor interaction derives its importance as it is the simplest of the interactions. The joint regression technique is employed to study the G x E interaction. The regression techniques are having the assumption of additivity of effects. When there is departure from these assumption the joint regression technique fails. Additive Main effects and Multiplicative Interaction studies have helped a lot at this juncture. Raju (2002) derived a more comprehensive measure of interaction based on AMMI model. This was achieved using the spectral decomposition of the relevant interaction matrix which enabled the study of interaction with the same precision as that of studying the main effects. Biplots formulations of interaction effects based on the PCA vector scores are the most simplest and explicit representation of interaction. The study of interaction based on spectral decomposition has been illustrated using the secondary data on the biometric, chemical and qualitative characters from the projects “Development of a bimodal phasic management system to improve both quantity and quality in Kacholam (Kaempferia galanga)” and “Development of a bimodal phasic management system to improve both quantity and quality in Njavara (Oriza Sativa)”. The DMRT tests for each level of the factors viz., calcium and source were carried out for the parameters viz., percentage content of phosphorus in rhizome, percentage content of potassium in rhizome and North – South foliage spread. In all these characters no specific interaction effect could be sorted out. These interactions when studied based on the factor analytical technique revealed that source II and second level of calcium had the highest positive interaction as regards the percentage content of phosphorus; source III and third level of calcium for percentage content of potassium and source II and third level of calcium for North – South foliage spread. When the order of the interaction matrix was high as in the case of the second experiment, DMRT tests failed to highlight the appropriate interactive effect in the characters viz., grain yield, percentage content of nitrogen in grain, percentage content of phosphorus in grain, percentage content of phosphorus in straw and percentage content of potassium in straw. The study based on the factor analytical technique revealed that the treatments T15, T8, T3, T1 and T4 respectively had the highest interactive effect with Payyanur for the above said characters where as for Badagara they were T3, T14, T4, T5 and T8 .ThesisItem Open Access Nonlinear models for major crops of Kerala(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 2007) Joshy, C G; KAU; Krishnan, SNonlinear modelling techniques are the most suited tools for describing any time series phenomenon. Among the various nonlinear models in vogue monomolecular, logistic, gompertz and mixed-influence models find a prominent place. With this idea the agricultural scenario of Kerala was measured through the three important descriptors namely area, production and productivity of the major crops viz; coconut, rubber, paddy, pepper, tapioca, cashew and banana for all the districts and the state as such. Monomolecular model was the most apt model in most of the cases. The data sets were further explored based on the carrying capacity achieved by 2002-03 coupled with intrinsic growth rate. When none of the nonlinear models were found satisfactory either simple linear regression model or quadratic model was tried to explore the nature of trend. Coconut production was found to have reached its near maximum in all the districts where it was a major crop but the productivity figures gave a warning note for increasing the productivity. Rubber was found to be one of the most gifted crops, which was not devoid of proper attention. Even with this stature, production of rubber can be improved through uniform management practices. Usually nonlinear and quadratic models aptly describe a time series data on crop production. It is astonishing that simple linear regression model aptly described the paddy production in the state. The regressive value of the regression coefficients indicated that paddy production in the state is facing extinction.Paddy production in the state has at least to be protected. The lack of fit of most of the nonlinear models and even quadratic models to the data of pepper production indicate the various devastating hazards that the crop faced with. These contrasting features bring out the fact that pepper cultivation be not allowed to be toyed with. The area specific crops like cashew, cardamom, coffee and banana be made nonspecific through innovative technologies. A concerted effort with valid stresses specific to each crop will make the agricultural scenario bright.ThesisItem Open Access Optimality of block designs used in one way elimination of heterogeneity(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 1995) Somy Kuriakose; KAU; Krishnan, SBlock designs are usually used in experiments where it is important to eliminate heterogeneity at least in one direction. From the class of designs it is desired to choose a design which will estimate the elementary treatment contrasts with maximum precision. The optimality criteria are based on the dispersion matrix of all possible elementary contrasts. The A-optimality criterion based on the information matrix was derived. Usually for comparing test treatments with a control RBD is used with the control treatment replicated in all blocks. The same objective could be achieved by using Balanced Treatment Incomplete Block Designs (BTIBD). BTIBD was found to be more efficient than RBD with the control treatment replicated in all blocks. Optimalities of BTIBD were also examined. When a BTIBD was augumented with certain number of blocks, such that the augmented blocks contains only the test treatments the resulting design was found to be E-optimal.ArticleItem Unknown Productivity of cashew as influenced by chlorophyll and leaf nitrogen content(Kerala Agricultural University, 1994) Latha, A; John, P S; Mercy George; Krishnan, S; KAUThesisItem Unknown Relationship between weed density and yield loss in semi- dry rice(Department of Agricultural Statistics, College of Horticulture,Vellanikkara, 2001) Shiji, C P; KAU; Krishnan, SSacciolepis interrupta and Isachne miliacea are two major problem weeds of rice in Kerala. An investigation on the quantum of crop loss incurred due to different densities of these weeds was undertaken to study the extent of damage inflicted on the crop which would necessitate early control of these weeds. The observations recorded on the various crop and weed characteristics were analysed as a 52 factorial experiment. It was found that crop characteristics like total bio- mass of paddy at harvest, number of tillers of paddy at harvest, number of productive tillers at harvest, grain yield and strain yield. And weed characteristics like number of tillers of S. interrupta at 60 DAS, height of S. interrupta at 60 DAS, number of tillers of S. interrupta at harvest of rice, dry matter production of S. interrupta and drymatter production of 1. miliacea were found to be affected by the weeds. The intra and interspecific competition was also brought to light based on the analysis. Single weed species models like that of Cousens (1985), Hakansson (1983), the first model of Watkinson (1981), Marra and Carlson (1983), Wilson and Cussans (1983), Wilcockson (1977) and Carlson et al. (1981) fitted well to the yield loss - S. interrupta/ 1. miliacea density relationship whereas those models proposed by Ngouajio et al. (1999), Kropff and Spitters (1991), Dew (1972), Zakharenko (1968) and Chisaka (1977) fitted well only to the yield loss- S. interrupta density relationship. The extended version of the Cousens (1985) model by Swinton et al . . (1994a) to a multi-species model was also fitted to the data and the same explained the yield loss - S. interrupta + 1. miliacea densities relationship to a considerable extent. The reduced form of the multispecies model to an equivalent single species model as worked out by Swinton et al. (1994b) also had a good fit. The numerical assessment of yield loss _. S. interrupta + 1. miliacea density relationship as illustrated by Berti and Zanin (1994) revealed the extent of damage on the crop by the weeds. The new curvilinear models tried also explained the yield loss - weed density relationship with the exception that the role of 1. miliacea deterring the yield of crop could not be highlighted due to its peculiar way of growth. The threshold weed densities worked out on a economic loss basis revealed that even the presence of two S. interrupta plants in a square meter area was hazardous for the crop whereas even the presence of 321. miliacea plants in the same stipulated area was not as detrimental as S. interrupta.ThesisItem Unknown Time series analysis and forecasting of the prices of Indian natural rubber(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 2017) Velpula Jhansi Rani; KAU; Krishnan, SThe study entitled “Time series analysis and forecasting of the prices of Indian Natural Rubber” is primarily intended to forecast the prices for Indian Natural Rubber (NR). For forecasting the prices, firstly, domestic NR price was decomposed it into time series components. Evaluation of growth, instability and relationship between the domestic and international prices in the pre WTO and post WTO periods were carried out in this study. For decomposition of domestic NR prices into time series components, additive decomposition was tried. The data were decomposed into trend, seasonal and cyclic components. The trend values proved that there was quadratic trend over the years. Seasonality indices revealed that the highest price was in June and lowest price in December. Cyclic components showed three cycles over a period of time under investigation. For evaluation of growth and instability, volatility and instability analyses were carried out for pre-WTO, post-WTO and overall periods in terms of rupees as well as dollars. Two types of volatility i.e., intra-annual volatility (within year dispersion) and inter annual volatility (between year dispersion) were calculated. Intra-annual and inter annual volatility were higher in post- WTO for international and domestic NR price series and the crude oil price showed higher volatility in pre-WTO period in terms of rupees as also in dollars. GARCH (1,1) model gave an additional evidence for persistence of volatility. It proved that the volatility persisted in the overall period in terms of rupees and dollars for domestic and international NR price. Instability analysis showed that the price instability in post-WTO period was almost double than that of pre- WTO period and it tripled in the overall period in terms of rupees. In terms of dollars, the instability in post-WTO and overall period was almost triple than pre-WTO period for domestic and international NR prices and crude oil prices showed almost double instability than pre-WTO period. iii The relationship between domestic and international NR prices were analysed through cointergration analysis and Vector error correction model (VECM). The direction of relation was drawn by Granger Causality test. Cointegration and Granger Causality test proved that there was at least unidirectional relationship among the variables. VECM analysis proved that there was long run relationship between domestic NR price, international NR price and crude oil price. It revealed that, a speed rate of adjustment 14.3 per cent was required for domestic NR price series to correct its previous period. There were many general factors affecting the prices of domestic NR like synthetic rubber production, crude oil prices, international rubber demand and supply, international transactions, exchange rates, natural factors and development of automobile industries. Stepwise regression analysis was used to sort out the factors affected in pre-WTO and post-WTO periods. In pre-WTO, domestic NR price was affected by international NR prices and in post-WTO by international NR prices and SR consumption. Domestic NR prices were forecasted with three different models like Stepwise regression method, ARIMA and SARIMA models. Stepwise regression method could be predicted when the variables like international NR prices and import value of NR were available. Among ARIMA and SARIMA models, ARIMA (4,1,4) and (4,1,4) (1,0,1) 12 was found to be best judged as per different statistical criteria for assessing the model fit and model adequacy.ThesisItem Unknown Weather paddy crop relationship(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1981) Krishnan, S; KAU; Surendran, P UAn effective regression method for the examination of the stability of the treatments in repeated experiments was introduced by Finlay and Wilkinson (1963). A new justification for the employment of this method was evolved and this does not require the logarithmic transformation of the data to induce linearity of regression. A treatment has greater than average, average or less than average stability according as the regression coefficient b 1. The data from permanent manorial trials conducted at Rice Research Station, Pattambi from 1973 to 1979 were used to show that the method of regression coefficients to study stability and the method of analysis of groups of experiments are equivalent. This was the first attempt in that direction. Method of analysis of principal components was used to suggest a new weather index based on rainfall and temperature which are considered to be important weather para meters. The number of wet days did not have any significant correlation with the mean yields of treatments. In the kharif season mean daily humidity was significantly correlated with the yield. Whereas all other parameters such as mean daily rainfall, mean daily temperature, mean daily maximum temperature, mean daily minimum temperature, maen daily maximum humidity, mean daily wind velocity and mean daily hours of sunshine did not have any significant correlation. In the rabi season mean yield of Jaya had a correlation of -0.5713 with the mean daily temperature, 0.91131 with mean daily maximum temperature, -0.6802 with mean daily minimum temperature -0.5888 with mean daily minimum humidity and 0.88193 with hours of sunshine. A modified procedure was suggested to estimate the weekly rainfall of a place. This was obtained by applying the method of Surendran et.al. (1977) to logarithms instead of the weekly annual rainfalls. Incidentally it gave a method for suggesting the adequacy of the length of the date for estimation. Theoretical distribution of the weekly rainfall at Pattambi were indicated. All of them were found to obey beta distribution.