Seed Orchard Views

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Chestnut Research Milestone Achieved at Penn State's Arboretum In the first test of blight resistance in the hybrid chestnut orchard in The Arboretum at Penn State, two strains of chestnut blight fungus were inserted, one in each of two small holes in the trunks of seedlings planted in 2002. History of the Orchard at Penn State

The orchard will continue to grow larger each year as more parent trees from the fourth generation reach maturity and begin intercrossing. Within five to ten years, the most promising of the families planted throughout the first few years will have been selected and will be producing the initial seed for restoration.

Seed orchards are a common method of mass-multiplication for transferring genetically improved material from breeding populations to production populations (forests) and in this sense are often referred to as multiplication populations. A seed orchard is often composed of grafts (vegetative copies) of selected genotypes, but seedling seed orchards also occur mainly to combine orchard with progeny testing. Seed orchards are the strong link between breeding programs and plantation establishment. They are designed and managed to produce seeds of superior genetic quality compared to those obtained from seed production areas, seed stands, or unimproved stands.

In first generation seed orchards, the parents usually are phenotypically-selected trees. In advanced generation seed orchards, the seed orchards are harvesting the benefits generated by tree breeding and the parents may be selected among the tested clones or families. It is efficient to synchronise the productive live cycle of the seed orchards with the cycle time of the breeding population. In the seed orchard, the trees can be arranged in a design to keep the related individuals or cloned copies apart from each other. Seed orchards are the delivery vehicle for genetic improvement programs where the trade-off between genetic gain and diversity is the most important concern. The genetic gain of seed orchard crops depends primarily on the genetic superiority of the orchard parents, the gametic contribution to the resultant seed crops, and pollen contamination from outside seed orchards.