GENOTYPE BY ENVIRONMENT INTERACTIONS IN TWO SELECTION LINES OF AFRICAN CATFISH (CLARIAS GARIEPINUS) FOR GROWTH AND SURVIVAL TRAITS IN DIFFERENT PRODUCTION SYSTEMS

Résumé

This study was designed to determine the extent of genotype by environment interaction (GxE) of African Catfish (Clarias gariepinus) for growth and survival traits and to support the decision on the best environment for selection of C. gariepinus for a wide range of farming conditions. We used two lines of C. gariepinus that had been selected for two generations in two production systems. One line was selected in small scale farms (SC) utilizing agricultural by products mixed with complete feed
(low line). The other line was selected in semi extensive scale (SE) using flow-through (pond combined with concrete tanks) with good quality feed (moderate line). The heritability for weight gain, specific growth rate and survival were generally higher (0.3), (0.5) and (0.5) respectively. In between pond and small scale farms (SC) (low line), the GxE effect was insignificant, and the genetic correlation between trait expressions between the two environments was (0.9). On the other hand, there as moderate G×E effect between pond and SE (moderate line). The genetic correlations of the same traits between these pair-wise environments were (0.7). It was concluded that the best environment for selection of African Catfish for growth and survival traits on genotype by environment interaction (GxE) is low-input pond environment. A single breeding program on
genotype by environment interaction (GxE) to select feed intake under standard pond environment is recommended for African catfish (C. gariepinus).