Browsing by Author "Prabhakaran, P V"

Now showing 1 - 20 of 28

Characterization of the pattern of rainfall in northern Kerala
(Kerala Agricultural University, 1988) Santhosh, K; Prabhakaran, P V
A first order Markov Chain model was applied to daily rainfall data of five selected reporting stations of northern Kerala with a view to characterize the rainfall p-.ttern in that tract. It was found that the mod^l was adequate in representing the rainfall pattern in almost all fortnights except a few at the beginning and at the end of the year. The equilibrium probability of occurrence of wet day showed increasing trend iall centres upto 12th, 13th or 14th fortnights and then decreased. The results indicated that the likely commencement af south-west monsoon was in ui>> 11th fortnight (June 1 to 15). Suitable probability distributions were fitted to estimate the rainfall probabilities. It was found that there was slightly higher chance at Irikkur and Mananthody to get sufficiently high rainfall during earlier fortnights (8th and 9th).
Comparision of path coefficient analysis and principal component analysis and principal component analysis in turmeric
(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1985) Geetha, U; Prabhakaran, P V
The discriminant function technique was adopted for the construction of suitable selection indices for rhizome yield in turmeric, utilising the characters selected through principal component analysis and path coefficient analysis and relative discriminating powers of these two multivariate techniques in identifying the pertinent characters aws also evaluated. Data on 18 biometric characters of 19 varieties of turmeric gathered from a field trial conducted by the Department of Plantation Crops, College of Horticulture, Vellanikkara, Trichur during the year 1977- 1978 were utilised for the study
Comparison of alternative methods for the control of experimental error in perennial crops
(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 1994) Seena, C; Prabhakaran, P V
The feasibility of using certain novel devices for the control of error in experiments on perennial crops was examined on the basis of actual experimental data and the resulting efficiency gain evaluated. A considerable amount of reduction in error variance was achieved by the application of analysis of covariance with suitable functions of pre-experimental yield as concomitant variable. Application of quadratic covariance resulted a substantial gain of precision in the analysis of data on coconut. Nearest neighbourhood analysis (NNA) resulted in a significant improvement of precision in the analysis of data in most of the experiments. Double covariance analysis involving suitable functions of pre-experimental yield and NN variable as covariates resulted in further reduction of experimental error. Pearce’s iterative NN procedure was found to be the best alternative method for reduction of error over the coventional method of stratification. A plot of eight trees was found to be optimum for conducting yield trails on coconut and cashew. The percentage of genetic variability to the total phenotypic variability in the yields of cashew, coconut and cocoa was estimated to be 77.7, 83.4 and 45.4 respectively. The result called for the use of calibration of the plots and choice of appropriate concomitant variables for the reduction of experimental error in designing experiments on perennial crops.
Comparison of transformations used in the analysis of data from agricultural experiments
(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 1997) Priya Menon, K; Prabhakaran, P V
Correlation of yield of PTB rice varieties with some weather factors
(Kerala Agricultural University, 1985) Prabhakaran, P V
Determination of the size and shape of plots for trials on cashew
(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1981) Remesh B Nair; Prabhakaran, P V
The present study whose objective is to evaluate the problems concerned with field experimentation on cashew was undertaken using the yield records of 625 uniformly treated cashew trees collected from cashew research station, Madakathara for a period of five years starting from 1976. A single row of trees was discarded on either side of the experimental field to eliminate border effect. Thus the experimental material consisted of 576 trees raised from same parental stock in a 24 x 24 compact block arrangement. The period 1976 to 1980 for which there was no change in treatment was considered to be the pre-experimental period and the year following the application of treatment was considered to be the experimental period. Observations on certain yield contributing characters pertaining to the year 1978 to 1979 such as height, spread and trunk girth were also gathered. Plots of different sizes and shapes were formed by combining yields of adjoining trees in various possible ways, a single tree being considered as the ultimate unit. The plots were grouped into blocks of different sizes and cv was worked out for plots of different dimensions when plots were arranged in blocks and not arranged. The trees were found to be highly heterogenous even though they were raised from the same parental stock. Single tree plots were found to be the most efficient when viewed from the point of view of maximum relative percentage information and consequently could be recommended for conducting field experiments on cashew. Two tree plots could also be recommended due to certain practical considerations shape of plot did not seem to have a consistent effect on variability. Fair field Smith’s equation gave a good fit to the data and the parameter ‘b’ was found to be high in both the cases when trees are arranged in blocks and when they are not arranged. It was observed that 2 plot blocks were the most efficient for conducting field experiments on cashew. The efficiency of blocking decreased with an increase in plot size. The result showed that experimental error could be considerably reduced by the use of incomplete block designs. As an effective method of controlling tree to tree variation the method of ranking based on their past performance can be adopted. Efficiency of local control was considerably increased by ranking of trees as compared to mere grouping of trees with respect to their geographical contiguity. Pre-experimental year’s yield was found to be the most important yield contributing character. Trunk girth of tree was also found to have significant influence on the inherent yielding ability of the trees. A selection index evolved was found to be strongly correlated with experimental yield. The correlation coefficient observed for this variate was higher than that for other yield contributing characters. Maximum efficiency in analysis of covariance was noted by using selection index as covariate. Efficiency of covariance analysis decreased with an increase in plot size. The optimum pre-experimental period for calibration and covariance analysis was found to be two year’s immediately prior to the start of the experiment.
Effect of levels of N, P & K on the uptake of nutrients and grain yield in cowpea
(Kerala Agricultural University, 1979) Mohan Kumar; Balakrishna Pillai, B; Prabhakaran, P V
Efficiency of covariance analysis in manurial trials on cashew
(Kerala Agricultural University, 1983) Prabhakaran, P V; Remesh B Nair
Estimation of leaf area in costus speciosus using linear measurements
(Kerala Agricultural University, 1983) Prabhakaran, P V; Sudha Devi, P K
Forecasting of rice yield using climatological variables
(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1986) Ajitha, T K; Prabhakaran, P V
Forecasting of sugarcane yield
(Kerala Agricultural University, 1991) Alphi Korath; Prabhakaran, P V
Genetic divergence in banana
(Kerala Agricultural University, 1985) Valsalakumari, P K; Sivaraman Nair, P C; Prabhakaran, P V
On the basis of multtvariate analysis 62 cultivars of banana belonging to different genomic groups were grouped into 8 clusters considering 22 characters simultaneously. The characters pulp/peel ratio on volume basis followed by the weight of fruit contributed the maximum towards divergence.
Genotypic variability correlation and path-coefficient analysis in turmeric
(Kerala Agricultural University, 1987) Geetha, U; Prabhakaran, P V
Data on 18 biometric characters of 19 varieties of turmeric gathered from a field trial were analysed and the various genetic parameters estimated. High heritability estimates were manifested by girth of mother rhizome at centre and height of the plant. The expected genetic gain from plant height was also high. The correlation studies revealed that all characters were positively related to yield. Path-coefficient analysis showed height of the plant and length of secondary finger were the major contributors towards the rhizome yield.
Measurement of perception of the importance of linkage activities in the transfer of technology of improved rice varieties
(Kerala Agricultural University, 1992) Abdul Rahiman Kunju; Prabhakaran, P V
An investigation was designed to measure the perception about the importance of linkage activities among the research, extension, client and input subsystems in the transfer of technology of improved rice varieties. The extension subsystem perceived its linkage activities with the research subsystem as less important. The research subsystem percieved its linkage with the input subsystem as less important and this was reciprocated by the latter also. The perception of the client subsystem about its linkage with the input subsystem was also poor. The extension subsystem was of opinion that its linkage with the client and input subsystem was important and this view was reciprocated by the client and input subsystems.
Optimum plot size for field experiments on turmeric (Curcuma longa L)
(Department of Statistics, College of Veterinary & Animal Sciences, Mannuthy, 1984) Gopakumaran Nair, B; Prabhakaran, P V
A uniformity trial on turmeric (Curcuma Longa. L.) was conducted at the experimental field of College of Horticulture, Vellanikkara, during the period from June 1983 to January 1984 to assess the nature and magnitude of soil heterogeneity of the experimental field, and to determine the optimum size and shape of experimental plots and blocks in conducting field trials on turmeric by different methods. At the time of harvest, the yield data from 864 plots each of size 0.6m x 0.75m were recorded separately, discarding the external border row.
Optimum plot size for field experiments with tapioca
(Kerala Agricultural University, 1974) Prabhakaran, P V; Thomas, E J
Optimum plot size for field trials with banana
(Kerala Agricultural University, 1978) Prabhakaran, P V; Balakrishnan, S; Mary George
The data from a uniformity triai on banana was analysed for finding the optimum plot size for conducting field experiments. The results showed that single plant plots were most efficient. The co-efficient of variation of yield decreased steadily with increasing plot size. The empirical law suggested by Fairfield Smith gave a satisfactory fit to the data. The number of replications required for providing estimates with 5% standard error decreased with increased plot size, but the total experimental material required was minimum when single plant plots were used. However, as banana plants are liable for disease incidence, three plant plots are suggested for experiments.
Optimum size and shape of plots in field experiments with cashew
(Kerala Agricultural University, 1983) Remesh B Nair; Prabhakaran, P V
The data from a uniformity trial were analysed to find the optimum size and shape of plots and blocks. Considerable variability was observed in the yields of trees eventhough they were raised from the same parental stock. The relative percentage information was found to be maximum in single tree plots both in the case when the plots are arranged in blocks and when they are not arranged. Thus single tree plots could be recom.nended as optimum for conducting field experiments on cashew. In order to avoid enhanced chance of loss in information with single tree plots as an alternative suggestion two tree plots could also be used for conducting field experiments on cashew. It was observed that two plot blocks were the most efficient for conducting field experiments on cashew. The Fair Field Smith's equation gave a good fit to the data on the 2 cases when the plots are arranged in blocks and not arranged. The relatively high value of the parameter 'b' indicated that genotypic variation was more predominant than positional variation.
Pattern of occurrence of rainfall and estimation of rainfall probabilities in northern districts of Kerala
(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1987) Santhoh, K; Prabhakaran, P V
Pre-harvest forecasting of sugarcane yield
(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1984) Alphi Korath; Prabhakaran, P V
Several yield prediction models were tried to examine their suitability for the pre-harvest prediction of yield of two varieties of sugarcane namely CO-997 and CO-62175 in different months of plant growth using biometric characters based on the data collected from the Sugarcane Research Station, Thiruvalla. The methods of multiple regression analysis, path coefficient analysis and principal component analysis were used for the above purpose. Multiple regression analysis using plant biometric characters revealed that cane yield could be predicted on the basis of observations on height of the cane, girth of the cane find estimated total leaf area per cane or area of third leaf from the seventh month after planting onwards with an accuracy in the range of 59*5 to 81.9 per cent. The estimated cane yield when multiplied by the number of canes in the plot will give an advance estimate of the plot yield Linear models with five biometric characters viz., height of the cane, girth of the cane, width of the third leaf determined from the selected plants of each plot and number of canes/tillers and number of leaves determined on a whole plot basis were sufficient to predict the plot yield of the crop as early as in the fifth month of plant growth with an accuracy in the range 68 to 90 per cent. Path analysis revealed that height of the cane and girth of the cane were the t wo important characters contributing towards cane yield in all stages of plant growth. Using the forecasting models fitted with principal components as explanatory variables, yield could effectively be predicted with 81.4. per cent accuracy for variety CO-997 and with 76 per cent accuracy for variety 00-62175 in the Sixth month of plant growth.