Raghavan, K CJimcy JosephKAU2019-06-242019-06-242007http://krishikosh.egranth.ac.in/handle/1/5810109746PGGenetic diversity of four geographically different goat populations in Trivandrum, Kottayam, Thrissur and Kozhikode districts in Kerala was analysed based on physical, biometrical traits and microsatellite markers. Based on physical traits, the populations were not very distinct and uniformity was seen with respect to coat colour, horn pattern, presence or absence of tassels or beard and hair pattern. The animals were predominantly horned and short haired with coat colour of white or a combination of white with either black or brown. Majority of animals did not possess tassels or beard. The biometrical traits observed in the present study were body measurements, peak yield and prolificacy. Body weight of adult female goats was predicted using the regression equation based on the power function of chest girth. It was shown that the animals of Trivandrum district had higher values for almost all body measurements and predicted body weight, while the Thrissur population had lowest values for these growth traits. Animals of Kottayam and Kozhikode came in between. Percentage of multiple births was also higher in Trivandrum goat population (68) compared to other populations indicating high prolificacy. Highest peak yield was recorded for Kottayam goat population. Discriminant analysis based on morphometric measurements revealed that the most discriminative variables were head width and body length, followed by shin circumference and rump length. Mahalanobis distance calculated based on morphometric traits indicated that Thrissur and Trivandrum populations were more distant, while least distance was observed between Kottayam and Kozhikode. Discriminant analysis based on body weight, peak yield and prolificacy revealed that only body weight and peak yield variables have significant discriminative capacity. Trivandrum, Kottayam and Kozhikode populations were grouped together in one cluster based on the distance value. Thrissur population was distant from all other populations. Microsatellite analysis revealed that all the five loci were highly polymorphic with five to nineteen alleles in different populations. The total number of alleles, the mean number of alleles per locus, mean heterozygosity and mean polymorphic information content were 51, 10.2, 0.8201 and 0.8104, respectively. The values indicate that the markers can be successfully used to study the variations existing in the populations. Based on Nei’s genetic distance Thrissur and Trivandrum population were grouped together first and then with Kozhikode population, while the Kottayam population formed a unique branch in dendrogram. Unrelated distance values produced by quantitative and molecular measures of variation may be attributed in part to the environmental influences and local selection pressures. Though use of more number of markers may possibly explain the variation encountered in these traits, the present investigation reveals that selection within each population for traits of economic importance like body weight and milk production is the best method to improve the performance of goats of Kerala.ennullThesis