A 10-year analysis of the high-density nursery (HDN) in the breeding of low-chilling peach and nectarine [Prunus persica (L.) Batsch] cultivars indicated selection was effective during the first cropping year for chilling requirement, fruit development period, size, color, shape and firmness but not for crop load, which needs to be evaluated at normal spacing over several years. The HDN system effectively has advanced the breeding program by promoting short generation time, reducing labor and space, and allowing for rating of some characters within 2 years from seed.