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19862
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Subject: Agricultural Statistics and Informatics × Author: KAU × End date: 1986 × Start date: 1986 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Standardisation of techniques of clustering genotypes using mahalanobis D2 and wilks ^ criterion
    (Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1986) Suresh, K M; KAU; Gopinathan Unnithan, V K
    Two major drawbacks of Tocher's method of clustering genotypes using Mahalanobls D were pointed out and animprovement over Tocher's method was suggested. The cluster configuration obtained by these two methods were compared with those obtained by canonical analysis method. A new computer oriented iterative algorithm for clustering using Mahalanobis D values was proposed. A procedure for formation of clusters statistically, using O V Mahalanobls Er was suggested to form maximum nonsignificant subsets of genotypes. A new measure of dissimilarity which does not require any assumption on distribution of the population, viz., the determinant of the pairwise scatter matrix was proposed in the study. Minimum /W/ criterion of Friedman and Rubin (1967) was also used for clustering. The clustering obtained by the new iterative algorithm using either Mahalanobls or determinant of pairwise scatter matrix or both could be used as the initial solution for it A graphical method for determining the optimum number of clusters was suggested The different methods were illustrated in two sets of data
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    ThesisItemOpen Access
    Standardization of field plot technique for cashew
    (Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1986) Lucyamma Mathew; KAU; Saraswathi, P
    The present study deals with a plot technique for conducting field experiments on a biologically heterogeneous tree crop cashew by applying a well known result in sampling theory that the clusters formed with negative intraclass correlation are relatively more efficient Cashew being a perennial crop are sensitive to variation in fertility status of soil in which they grow, susceptable to mishaps, long gestation period etc Because of their large size and long life they are considerably different from annuals or field crops as to need special considerations in designing experiments with them. The experimenter is always faced with the dlffiiculty of getting uniform experimental trees on account of the biological variation present among the individual trees. The difficulty in getting experimental trees with uniform yield or some other measurable characteristic of the tree and some considerations in overcoming this problem is discussed. Achieving greater homogeneity between plots within a block by creating greater heterogeneity within plots is found to be a better field plot technique for experiments with adult trees on cashew. Similar techniques are also applicable to other plantation crops which are subjected to high biological variation.