Báo cáo nghiên cứu nông nghiệp " Seed-Producing Stands " pot

Seed-Producing Stands There are many methods to obtain seed for planting • Meeting immediate needs – Seed from individually good phenotypes – Seed from seed stands/seed production areas • Meeting long-term needs – Seed from seed orchards • These seed sources are different in genetic quality Why not just collect seed out of plantations? • We may not know the genetic origin of the plantation – it could be inferior, or the genetic base too narrow. • There has been no selective thinning to remove inferior trees in the plantation. • The inferior trees contribute their pollen to the other, better trees in the plantation, lowering seed quality. Why not just collect seed out of plantations? • Because the trees are growing at close spacing, flowering may be poor, resulting in inbreeding and poor genetic quality of seed. • Much better to get our seed from well-managed seed-producing stands. Collect seed from superior trees only when seed is needed for immediate planting Inferior trees contribute pollen to better trees Types of seed producing-stands • Seed stand • Seed production area • Seed orchard – Seedling seed orchard – Clonal seed orchard Seed Stand An area of planted or natural forest of superior appearance (phenotype) but unknown genetic potential Teak seed stand, Thailand Seed Stand A mature plantation of Eucalyptus regnans. We may not know the original seed source. Seed Production Area • Plantation raised from suitable provenance, selectively thinned and managed for seed production • At least 20 unrelated families to minimise inbreeding • Family identity of individual trees not known • Heavy selective thinning removes inferior trees, retaining good trees to produce seed • Produce seed of somewhat improved quality E. camaldulensis SPA, Laos Seedling Seed Orchard • Developed by selective thinning a progeny trial which tests many (>100) different families of a species • Progeny trial reveals which families and trees are growing best • Inferior trees are removed in 2-3 thinnings • All trees of some inferior families may be completely removed • Family identity of every tree is known • Seed from the best trees of the best families have the best genetic quality – producing best plantation A. crassicarpa SSO, Thailand . Seed-Producing Stands There are many methods to obtain seed for planting • Meeting immediate needs – Seed from individually good phenotypes – Seed from seed stands/ seed production. well-managed seed-producing stands. Collect seed from superior trees only when seed is needed for immediate planting Inferior trees contribute pollen to better trees Types of seed producing -stands •. area of planted or natural forest of superior appearance (phenotype) but unknown genetic potential Teak seed stand, Thailand Seed Stand A mature plantation of Eucalyptus regnans. We may