Chromosome analysis on different breed types of water buffaloes (Bubalus bubalis) was undertaken to identify their karyotypes and to determine the pattern of chromosome segregation in crossbred water buffaloes. Altogether, 75 purebred and 198 crossbred buffaloes including 118 from Malaysia and 80 from the Philippines, were analyzed in this study. The diploid chromosome number of the swamp buffalo from both countries was 48 and that of the river buffalo was 50, while all F1 hybrids exhibited 49 chromosomes. The F2 hybrids consisted of three different karyotype categories (2n = 48, 2n = 49, and 2n = 50), whereas the backcrosses included two different karyotype categories each, with 2n = 48 and 2n = 49 in the three quarters swamp types and 2n = 49 and 2n = 50 in the three quarters river types. Chi-square tests on pooled data from Malaysia and the Philippines indicated that the distribution of different karyotype categories of F2 animals did not deviate significantly from the 1:2:1 ratio expected if only balanced gametes with 24 and 25 chromosomes were produced by the F1 hybrids. In the three quarters swamp and three quarters river types, the respective karyotypic categories were in ratios approximating 1:1. The distribution of chromosome categories among the F2 hybrids and backcrosses suggests that only genetically balanced gametes of the F1 hybrids are capable of producing viable F2 and backcross generations.

No abstract

No abstract

No abstract

Measurement values of sixteen external characters and karyotypes were described for one female and five males of the adult captive tamaraws, Bubalus (B.) mindorensis endemic to the island of Mindoro. Principal component analyses among bubaline species, using nine or ten of the characters as variables, derived more than 95% of total variance on the first component axis, in which the tamaraw was located almost at the midpoint of two distant bubaline groups : the dwarf water buffaloes of Sulawesi (Anoa depressicornis and A. quarlesi) and the Asiatic water buffaloes (the swamp and the river types of Bubalus bubalis). All the six tamaraws had 46 chromosomes in diploid form (2N) and 58 as the fundamental number (FN) including the sex