Stock improvement of silver barb (Barbodes gonionotus Bleeker) through several generations of genetic selection

This paper reports stock improvement of silver barb (Barbodes gonionotus Bleeker) using selective breeding techniques and presents the results of three generations of growth performance between selected and nonselected control groups. The breeding program was initiated using two wild caught populations from Thailand and Indonesia and an existing local stock from Bangladesh. To produce the parental base population in 1996, the three unrelated founder stocks were mated through a complete 3 X 3 diallele crossing experiment to produce nine heterogeneous, outbred genetic groups. In 1997, the first generation (F1) trials were made. For each of the six reciprocal crosses, five to eight pairs were mated separately and the best three progeny groups were selected on the basis of egg fertilization rate, lack of deformities, healthy movement, and survival to make 18 full sib progeny lines. These were then communally stocked by mixing equal numbers of larvae from each family and grown until maturity in ponds. During the spawning season of 1998, the heaviest 20% of mature females and males were mass selected from the F1 communal crossbred group and mated to produce the F2 generation. In 1999, mass selection was again performed, selecting 15% of the best mature breeders from the F2 generation to produce the third generation (F3) for trials. In each generation, evaluation of growth performance was carried out through comparative trials between selected and nonselected control (existing stock of Bangladesh, B X B) groups. A 7.5% genetic gain in growth performance was attained by the F1 crossbred group over the nonselected control group. The F2 and F3 selected groups attained 2.3% and 12.1% cumulative weight gain, respectively, over two generations. The average gain per generation across two generations of selection for growth performance in weight was estimated as 7.2%. The weight gain values of the third generation of the selected group showed 21.9% superiority over the nonselected control. Present findings suggest that the method for improvement of silver barb through several generations of genetic selection might be a useful technique for other carp species in Bangladesh and elsewhere in Asia.