AfDB| Zambia Aquaculture Enterprise Development Project. (ZAEDP), End of Project Report Genetic Improvement Program for Oreochromis andersonii and Report on Production and Performance Assessment of F2 (G1), April 2024

Abstract

Under this project this project the following have been achieved. 1- we have been able to make essential steps in the practical development of the national GIP by developing a base population and subsequent selected populations upon which the breeding program would be continued in the future. Building on the base population (F1 or G0) to produce the first selected O. andersonii generation (F2 or G1). The latter represents the first ever documented case of formal genetic improvement for O. andersonii. 2- Initial assessments of the base population that was developed from a diallel cross of three populations (NARDC, Luangwa and Super upper Zambezi), indicated a significant heritability estimate (h2) of 0.58 implying a great potential for selective breeding of O. andersonii. The current assessments of the first selected generation (F2/G1) combined have further indicated a significant heritability estimated of 0.35 and a genetic improvement of the selected G1 over the base population G0 of up to 12.92% genetic gain. 3- The heritability estimate for harvest weight was moderate and statistically significant at 0.35 ± 0.08 but, as anticipated, lower than that obtained in the analysis of G0 data alone. Family, hapa and additive genetic effects could not be separated in the analysis of G0 data (as there were no known genetic relationships between G0 families) and, thus, the estimate of the additive genetic effect and heritability in the G0 analysis was likely inflated. The estimated narrow sense heritability (h2) of 0.35 is close to an estimate (h2=0.38) previously obtained in the Abbassa O. niloticus breeding program (Charo-Karisa et al., 2006) and suggests that a favorable response to selection for weight at harvest can be expected in the O. andersonii breeding program taking place at NARDC. 4- A dissemination strategy was developed to guide Government on the sustainability of the O. andersonii program in the face of market and industry dynamics. The estimated genetic gain of 12.60% in G1 was encouraging, and it is recommended that the progeny of G2 of this improved seed (that is G3) should be distributed to the multiplier hatcheries. Distributing improved seed with sufficient gain is essential so farmers can appreciate the improvement and its benefit. This will provide an appreciative and good understanding that genetic gain delivers adequate benefit to the breeding program's farmers, clients and possible donors.