REPRODUCTION CONTROL

Monosex Tilapia Production through Androgenesis: Verification of Androgenically Produced Males,
Their Viability, and the Influence of the Female on Progeny Sex Ratios

Reproduction Control Research 6B (9RCR6B)/Study

At the time the Ninth Work Planwas printed, the PMO had approved this study for funding, but formal subcontract work was still in progress. The proposed investigation was a three-part study under work plan code 9RCR6, "Monosex tilapia production through androgenesis." In subsequent negotiations, the scope of the original research plan was restricted to include only one of the three proposed studies, "Selection of individuals for sex inheritance characteristics for use in monosex production (9RCR6A)," which was published in the Ninth Work Plan.

Monosex Tilapia Production through Androgenesis:
Growth of Genetically Derived Males in Production Settings

Reproduction Control Research 6C (9RCR6C)/Study

At the time the Ninth Work Plan was printed, the PMO had approved this study for funding, but formal subcontract work was still in progress. The proposed investigation was a three-part study under work plan code 9RCR6, "Monosex tilapia production through androgenesis." In subsequent negotiations the scope of the original research plan was restricted to include only one of the three proposed studies, "Selection of individuals for sex inheritance characteristics for use in monosex production (9RCR6A)," which was published in the Ninth Work Plan.

Reproduction Control Research 7 (9RCR7)/Study

The objectives of 9RCR7 were to use androgenetic procedures to develop direct induction of YY-male Nile tilapia. This was to be done using an induction protocol whereby phenotypic markers would indicate males in the broodstock. While use of the induction protocol has shown some success, the production of viable androgenotes has been low. After two years of applying the induction protocol, none of the androgenotes survived beyond early juvenile development. Since no androgenotes have reached maturity, the hypothetical 1:1 sex ratio of androgenotes cannot be verified and further progeny testing of the putative YY males cannot be accomplished so as to test the hypothesis of all-male progeny in breedings with putative YY males.