Abstract
Seeds of catla, rohu and mrigal from 9 sources (3 riverine and 6 hatcheries) were stocked in separate
ponds (2 decimal each) and their growth (length and weight) was monitored for 6 months. Catla of
Halda (190.55±15.64g) and Jamuna (191.79±15.22g) showed similar growth performance but significantly
higher than Padma and hatchery sources. Growth of Halda rohu (119.85±18.57g) was significantly
(P<0.05) higher than wild and hatchery sources. Halda mrigal showed significantly (P<0.05) higher
growth (121.07±15.29g) than Jamuna, Padma and hatchery sources. Genetic characterization of three
species using allozyme and microsatellite DNA markers were done. In allozyme electrophoresis the 7
enzymes (LDH, MDH, PGM, GPI, AAT, ADH and G3PDH) encoded by 7 presumtive loci were screened.
No polymorphic locus was found in catla. Four polymorphic loci were found in rohu (Mdh-1*, Pgm*, Gpi1* and Gpi-2*) and three polymorphic loci were found in mrigal (Mdh-1*, Mdh-2* and Gpi-1*). The mean
proportion of polymorphic loci, the mean proportion of heterozygous loci per individual, the average
observed heterozygosity (H,) and expected heterozygosity (H) were 42.85, 15.77, 0.125 and 0.184%
respectively for wild populations of rohu which were higher than the hatchery populations. The highest
gene flow value (26.725) found in the Halda and the Jamuna river populations indicate the close
relationship among them. In mrigal the mean proportion of polymorphic loci, the mean proportion of
heterozygous loci per individual, the average observed heterozygosity (H,) and expected heterozygosity
(He) were 28.57, 10, 0.086 and 0.148% respectively for wild populations which were also higher than the
hatchery populations. The highest gene flow value (87.278) found in Rupali-1 and Bismillah hatchery
populations indicate the close relationship among them. For microsatellite analysis, samples were
collected from catla, rohu and mrigal of three riverine sources and 6 microsatellite markers were used for
each of the species (Ccat A12, Ccat C3, Ccat C6, Ccat C8, Ccat G1, & Ccat G2 for catla, Lr3, Lr12, Lr14b, Lr21,
Lr24 & Lr26 for rohu and MFW1, MFW2, MFW17, Bgon22 and Barb54 for mrigal). The average observed
heterozygosity (Ho) and the average expected heterozygosity (He) was highest in the Halda catla
population (0.6250 and 0.7156, respectively). Relatively high level (0.0653) of FsT and low level (3.5311) of
gene flow (Nn) was detected between the Halda and the Padma catla populations. In rohu the average
observed heterozygosity (Ho) was highest (0.633) in the Padma population and the average expected
heterozygosity (He) was highest (0.607) in the Jamuna population. Relatively high level (7.043) of gene
flow (Nm) was detected between the Jamuna and the Padma rohu populations. On the other hand, low
level (3.417) of gene flow (N,) was detected between the Halda and the Padma populations. In mrigal
the observed heterozygosity (Ho) was highest (0.400) in the Padma population followed by the Halda
(0.383) and the Jamuna (0.377) populations. The highest (0.0257) population differentiation (FST) value
was observed between the Halda and the Padma populations while the lowest (0.0143) was observed
between the Padma and the Jamuna populations. The highest gene flow (N,) was between the Padma
and the Jamuna populations (17.1756) and lowest between the Halda and the Padma populations
(9.4832). F1 generation of rohu and mrigal was produced through breeding of selective stocks. F1 rohu
(growth increment: length 9.5% and weight 9.2%) and mrigal (growth increment: length 8.7% and
weight 17.35%) showed better growth compared to their parents under same management practices.