Forestry and Forest Products Selection concepts Isolation, inbreeding and relationships in forest trees Forestry and Forest Products Isolation, inbreeding and relationships in forest trees 1. Phenotype 2. Selection (seed orchards, seed prod areas) Why is selection important? We want the best! Do we want big trees? Tree Quality P = G + E P = G + E Is environment important? E Environment ↕ Natural environment + Silvicultural Genetics & silviculture together Genetic diversity P = G + E P = G + E Product = genetics + environment Product = genetics + environment Tree Quality Is environment important? Forestry and Forest Products Propagation Population (seed orchards) Selection Breeding Population Base Population Activity cycle for tree breeding Crossing Planting stock for plantations [...]... 1 Plot 6 Family 6 Forestry and Forest Products Self-fertilised family inbreeding depression of yield pollen seed Forestry and Forest Products Inbreeding depression of growth in control-crossed progenies of E camaldulensis (Petford) at 30 months - trial near Gympie, Queensland outcrossed selfed Forestry and Forest Products Inbreeding problems Petford Vietnam landrace Petford Rwanda landrace E camaldulensis:... trees pollen seed Forestry and Forest Products Seed production area (SPA) – unpedigreed Forestry and Forest Products Seed production area – unpedigreed 1st thinning Forestry and Forest Products Seed production area – unpedigreed 2nd thinning Forestry and Forest Products Further thinning and selection 80% culling Original population mean Selected population mean Selected trees to be intercrossed to produce... camaldulensis: natural seed source vs local land race Australian seedlot (collected from natural stand, one year younger) Vietnam land race Forestry and Forest Products Open-pollinated eucalypt family insects are the main pollinators pollen pollen pollen seed 70% outcrossed 20% selfs 10% inbred (relative mating) Forestry and Forest Products Within-plot thinning of seed orchards First assessment Replicate... 6 Forestry and Forest Products Within-plot thinning of seed orchards Second assessment Replicate 1 Plot 1 Replicate 2 Related trees adjacent - mating results in inbreeding Plot 2 Family 2 Plot 1 Family 3 Family 3 Plot 2 Family 5 Plot 3 Family 6 Plot 3 Family 4 Plot 4 Family 5 Plot 4 Family 1 Plot 5 Family 4 Plot 5 Family 2 Plot 6 Family 1 Plot 6 Family 6 Forestry and Forest Products Within-plot thinning... 5 90 m Forestry and Forest Products 60 ½ -sib families 5 reps x 5 rows x 3 m = 75 m 42 30 m 24 5 Rep 5 41 4 Rep 4 1 3 Rep 3 2 Rep 2 Row 1 2 3 4 5 Rep 1 5 tree row plots 5 replicates each family occurs only once in replicate Within-plot thinning of seed orchards First assessment Replicate 1 Replicate 2 Plot 1 Family 2 Plot 1 Family 3 Related trees adjacent - mating results in Plot 2 inbreeding Family... breeding Selection Base Population Propagation Population (seed orchards or clone hedges) Crossing Breeding Population Planting stock for plantations 6 Genetic gain Gain ƒ ( i h2 σp ) Where: σp → variability h2 → genetic control i → selection intensity Selection for development of seed orchards We selectively thin unpedigreed seed production areas, and pedigreed seed orchards, to achieve genetic gain... thinning of seed orchards Third assessment Replicate 1 Replicate 2 Unrelated trees adjacent Plot 1 - outcrossing Family 2 Plot 1 Family 3 Plot 2 Family 3 Plot 2 Family 5 Plot 3 Family 6 Plot 3 Family 4 Plot 4 Family 5 Plot 4 Family 1 Plot 5 Family 4 Plot 5 Family 2 Plot 6 Family 1 Plot 6 Family 6 Forestry and Forest Products Outcrossed family (control-pollinated single-pair cross) Unrelated parent trees. .. Selection for development of seed orchards We selectively thin unpedigreed seed production areas, and pedigreed seed orchards, to achieve genetic gain Must thin to one tree per plot in seedling seed orchards, to avoid inbreeding within families Seedling seed orchard with 60 ½-sib families Col 1 2 3 4 5 6 7 8 9 10 11 12 35 57 47 45 36 10 5 4 52 46 2 15 55 37 58 12 11 26 43 18 49 53 22 50 8 40 34 13 48 30... Products Further thinning and selection 80% culling Original population mean Selected population mean Selected trees to be intercrossed to produce next generation 90% culling Original population Selected population mean mean Selected trees to be intercrossed to produce next generation  . Forestry and Forest Products Selection concepts Isolation, inbreeding and relationships in forest trees Forestry and Forest Products Isolation, inbreeding and relationships in forest trees. trees adjacent - mating results in inbreeding Forestry and Forest Products Self-fertilised family - inbreeding depression of yield seed pollen Forestry and Forest Products selfed outcrossed Inbreeding. to achieve genetic gain ¾ Must thin to one tree per plot in seedling seed orchards, to avoid inbreeding within families Forestry and Forest Products Col 1 2 3 4 5 6 7 8 9 10 11 12 Rep 1 1 1412442355747453610