Project title: Selective breeding based on natural spawning & mate selection in Nile tilapia
PhD student: Yonas Fessehaye
Short description of the proposed research:
The general objective of this study is to investigate the natural mating system of the Nile tilapia, Oreochromis niloticus in ponds. According to the mate choice theory, individuals in some species prefer mates carrying dissimilar genes at the major histocompatibility complex (MHC) which may function to increase the MHC or overall heterozygosity of progeny. This MHC-heterozygosity of progeny is suspected to confer resistance to infectious diseases. Another objective is to reconstruct the family pedigree of naturally mating tilapia using microsatellite genotyping. This pedigree tracing will enable us to estimate progeny growth and survival without the need of separate rearing facilities or tagging of individuals. In addition, the rate of inbreeding, response to selection and other genetic parameters could be estimated under natural mating systems. Finally the information obtained will be translated to design a breeding strategy for a natural reproducing tilapia population where genetic gain is maximised with out compromising fitness due to inbreeding.
The project objectives are:
1. Investigating the contribution of parents to the next generation and identify the factors
that contribute to the differential reproductive success of parents under natural mating.
2. To investigate if there is evidence for disassortative mating based on MHC gene variation in Oreochromis niloticus.
3. Investigate the effect of inbreeding in both natural mating and paired matings.
4. The information on mating structure, molecular pedigree and other genetic parameters will be used to develop
a selective breeding program that maximises genetic gain with minimal accumulation of inbreeding.
Composition of the scientific support project group:
Dr. Prof. V. Arendonk Supervisor WUR /Animal Breeding & Genetics
Dr.ir. Hans Komen Co-Supervisor WUR /Animal Breeding & Genetics
Dr. ir. Henk Bovenhuis Advisor WUR /Animal Breeding & Genetics
Dr. Mahmoud Rezk Advisor WorldFish Center, RRC for Africa and West Asia, Abbassa, Egypt