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ThesisItem Open Access Statistical approach on the pattern of development of shank length in ducks(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1989) Sunanda, C; KAU; George, K CThe present investigation entitled ‘‘statistical approach on the pattern of development of shank length in Ducks’’ has been undertaken to study the following objectives. 1. To examine the pattern of development of shank length in two breeds of ducks in University Duck Farm, Mannuthy. 2. To compare them (a) between genetic group (b) between males and females within each genetic groups (c) between males of genetic group (d) between females of genetic group and 3. To fit appropriate growth curves for prediction of body weight through shank length at different stages of growth. For this purpose shank length and body weights on 14 males and 25 females of Desi ducklings and 26 males and 26 females of White Pekin (WP) ducklings were utilized. The ducklings were reared for twelve weeks in Kerala Agricultural University Duck Farm, Mannuthy under uniform feed formula and identical management practices. In the day old and the twelfth week of age uniformity could be seen in the mean shank length of the four groups. But at the fourth and eighth week of age, mean shank length of the four groups was not uniform. Upto ninth week of age, Desi females had higher shank length than the other three groups except at the fifth week. But during the fifth, tenth, eleventh and twelfth week of age Desi males had the highest shank length. The least shank length was always observed for WP males. During the entire period, Desi ducklings had higher shank length than WP duckling. The growth pattern of body weight was not uniform in the four groups except the initial body weight. High correlation was found between the body weight and shank length. It revealed that shank length can be made a criterion for selection for higher body weight. The method of comparison of growth rates recommended by Rao (1958) was found unsuitable for the present study. Among the functional relationships worked out linear, exponential and second degree equations were found to be unsuitable for fitting shank length as a function of age. Modified exponential, logistic, Gompertz and Von-Bertalanffy equations were found to be suitable for fitting shank length over a period of time. Among these four, Gompertz was found to be the best fit. The second best fitted equation was logistic. Graphs of the best fitted equations ie. Gompertz and logistic were drawn for all the six group along with the observed values. This also confirms above result. Among the two functional relations ie. linear and exponential used for predicting body weight from shank length, exponential was found to be most suitable.ThesisItem Open Access Comparative study of genotype environment interactions in Sesame(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1989) Mini, C J; KAU; George, K CThe present study has been conducted to choose a consistent variety for all the regions and all seasons in the light of genotype-environment interaction with the following objectives. (i) to evaluate the existing techniques available for studying GE interaction in sesame (ii) to develop new concepts and methods to solve some problems peculiar to crop sesame like non-linearity of interactions, non-orthogonality of data and different patterns of genotype-environment (GE) interactions that are encountered while studying the stability of varieties simultaneously for several traits.ThesisItem Open Access Biennial tendency among coconut hybrids- a statistical study(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1989) Lathy, K S; KAU; Saraswathy, PThe present study deals with the objective of estimating the magnitude of biennial tendency among coconut hybrids and WCT and to test for their significance. Non parametric and parametric approaches were tried for the study. The intensity of crop fluctuations was also estimated. The magnitude of biennial tendency was 100 per cent, 52.26 per cent and 84.34 per cent respectively for the WCT palms taken from RARS, Pilicode; RARS, Kumarakam and CRS, Balaramapuram. 100 per cent bienniality was observed for the WCT palms which were subjected to NPK manuring and for the hybrid varieties NCD, LO x GB and CC x GB palms. 97.59, 94.12, 80, 83.33, 80, 71.42, 66.67, 95.69, 88.89 and 25 per cent of the palms of WCT x CDG, WCT x GB, AO x GB, Java x GB, LS x GB, T x G, T x SS, T x D, T x GB and komadan exhibited biennial tendency. T x AD and T x LD palms showed only 14.29 per cent bienniality. Intensity of crop fluctuations was less than 50 per cent for almost all these varieties. The distribution of palms in the ‘on’and ‘off’ phase also established the existence of biennial tendency. The test of significance of biennial tendency established the existence of biennial tendency established the existence of biennial tendency among all the WCT and hybrid palms except for T x AD and T x LD. The time-trend was not found to be a significant characteristic for almost all the varieties. WCT palms which were subjected to fertilizer management during the period of the study and WCT x cdg palms were found to be influenced by both the time-trend and biennial tendency.ThesisItem Open Access Optimum stratification for yield estimation in cocoa (Theobroma Cacao L.)(Department of Agricultural Statistics, College of Horticulture, Vellanikkara, 2000) Sunil Kumar, G; KAU; Gopinathan Unnithan, V KInvestigation on "Optimum stratification for yield estimation In cocoa (Theobroma cacao. L)" was carried out in the department of Agricultural Statistics, College of Horticulture, V ellanikkara during 1997-99 using data on 1025 'F orestro' variety cocoa trees from the Cadbury-KAU Co-operative Cocoa Research Project (CCRP), College of Horticulture, Kerala Agricultural University. Four different stratification rules, viz, cumulative root 'f rule, cumulative cube root 'f rule, Ekman's rule and an iterative procedure for function minimisation, were used to arrive at boundary points of strata. For each of these rules stratification was carried out on average yield of yester years, canopy spread, value of HxG2 where 'H' is height and 'G' is the girth of the trees, the first principal component derived from these variates and height and girth of the trees and regression estimate of the study character with the predictor variables mentioned above. Sampling variance of the estimator of the population mean under Neyman allocation for two to five strata situations was estimated in each case, assuming a uniform sample size of 200. Different stratification rules and stratification variables were compared using these estimates. No single rule was found to be appropriate for all the stratification variables and for different number of strata. But in most of the cases the cumulative root 'f rule was found to be good for smaller number of strata followed by the cumulative cube root 'f rule. For large number of strata, the iterative procedure performed consistently well compared to all the other methods. In the case of stratification based on the canopy spread, the Ekman' s method was found to be good for different numbers of strata. Regarding the stratification variables, the average yield of yester years was found to be best followed by the regression estimate in the sense of resulting in smaller sampling variance of the estimator of the population mean. Stratification based on value of HxG2 and the first principal component were found to be inferior. Average yield of yester years or regression estimate of yield could be used as covariate to perform the analysis of covariance for experiments in cocoa and also blocking of trees could be done based on these for the conduct of planned experiments on cocoa.