Optimization of the Structure of a Nucleus Breeding Program under Genotype-Environment Interaction Effects Using Simulation

Subject Areas :

A.A. Shadparvar ¹ , Z. Nouri Sigaroudi ² , A. Safari ³

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Received: 2025-01-30 Accepted : 2025-06-11 Published : 2025-09-01

Keywords: breeding program, genetic gain, genetic variance, genotype-environment inter-action, stochastic simulation,

Abstract :

A crucial challenge in nucleus breeding programs is the potential impact of genotype-environment interac-tion (GxE) on identifying the optimal configuration. This study aims to investigate the optimal structure of a nucleus breeding program in the presence or absence of GxE effects. Thirty-six distinct scenarios were created based on two levels of nucleus size (5% and 15% of population), three levels of female transfer rate from the base to the nucleus (0, 25 and 50%), three levels of male transfer rate from the nucleus to the base (25%, 50 and 100%). The mean genetic value in the last generation of the nucleus was higher than that of the base population, due to initial selection for nucleus formation and the selection method applied in sub-sequent generations. The mean genetic value in the nucleus ranged from 19.75 to 23.89, while in the base population, these values ranged from 17.16 to 23.76. Genetic gain in the nucleus over 20 generations ranged from 11.82 to 14.89, whereas in the base population, it fluctuated between 12.26 and 18.87. Genetic vari-ance in the 20th generation ranged from 0.1 to 5.08 in the nucleus and from 0.18 to 9.02 in the base popula-tion. Overall, the presence of GxE interaction led to a reduction in both genetic mean and genetic gain in the nucleus and base populations. The findings indicate that GxE interaction can influence the optimal structure of base populations in a nucleus breeding program.

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