Number of pages: 11
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Open Access: green
If the generation interval can be reduced from four to three years genetic gain per year can be increased by 33 % given else similar conditions. In Atlantic salmon this can be obtained through the production families that are put into the sea as 0+ autumn smolt instead of 1+ spring smolt. Genetic parameters were obtained for growth and sexual maturity (either or trait) based on traits records on fish from the same families from each of three different year-classes (2006, 2009 and 2010) that were put into the sea as 0+ autumn smolt and 1+ spring smolts. The trait records were obtained after one winter in the sea for two of the 1+ year-classes (2006 and 2009) and after two winters in the sea for all three 0+ year-classes. For the 1+ fish percent early sexual mature fish was 11.9 % (2006) and 7.6 % (2009), and for the 0+ fish 27.0 % (2006), 60.2 % (2009) and 33.1 % (2010). The genetic variation for sexual maturity was substantial for the 0+ fish, but much lower for the 1+ fish, while the genetic correlation between these traits was close to zero in both year-classes (0.21±0.18; -0.02±0.10). The genetic variation for body weight was substantial for both the 0+ and the 1+ fish, and with a high genetic correlation between these traits in both year-classes (0.78±0.07; 0.76±0.05). It is concluded that if generation interval is reduced to three years and early sexual maturity is an important trait for fish put into the sea as 1+ smolt, the breeding nucleus families should also be tested as 1+ smolt.