Genetic improvement of ash in British forestry: Floral Diversity of Ash- Fraxinus excelsior Jo Clark National School of Forestry University of Central Lancashire

Introduction UK lowest forestry cover in Europe except Ireland (11%) Shift away from coniferous plantations to broadleaves, higher grant rates Influx on non native, non adapted material Ash is second most commonly planted hardwood Prone to forking and poor form without proper silviculture Need for tree improvement on hardwood species Reduction in rotation time and better form

Problems With Growing Quality Ash Ash bud moth Prays fraxinella Ash canker Nectria galligena Frost damage

Set up in 1991 to improve the quality of planting stock available to the forester Comprised of landowners, academics and interested parties Preferred improvement technique that of the Breeding Seedling Orchard – BSO (Barnes 1995) BIHIP – The British and Irish Hardwood Improvement Programme

Stages in a Traditional Tree Improvement Programme 1.Identification of phenotypically superior (plus) trees 2.Collection of reproductive material – either seed or scion 3.Establishment of progeny trials 4.Selection of best performing individuals for seed orchard establishment 5.Orchard of improved seed bearing trees

Traditional Vs BSO Approach Plus Tree Selection BSO Progeny Trial and Seed Orchard 20 Years Improved Seed in 20 Years Plus Tree Selection Progeny Trial Seed Orchard of Proven Individuals 20 Years Improved Seed in 40 Years

Plus Tree Selection

Ash BSO Design and Layout 36 families of half sibs 4 orchards of replicated units varying from 720 to 1296 trees Randomised block design with double buffer row Not all families are present in each orchard 4264 trees in total

BSO Assessment: Form Major Kink Classic Fork Severe SweepsPerfect Tree

Mean Height of Families Recorded at Four BSOs in 2001

Family Performance for Height

What to Rogue? How many trees should be left? Should we select individual trees, ie, the top 150 individuals? Or should we select the top families? What about gender?

Genetic Gain Calculations for Height Scarr = 32 families Mulgrave Estate = 21 families Little Wittenham = 36 families Little Hidden Farm= 27 families

Floral Biology of Ash Wind pollination A polymorphous species exhibiting a continuum of gender Staminate flowersPistillate flowers

True Hermaphrodite

Hermaphrodite Flowers Anther Filament Stigma Style

Predominantly hermaphrodite flowers with some pure male inflorescences

Predominantly Male Flowers

Predominantly Female Flowers

Male Inflorescence With the Terminal Flower Female

Seed Development

Questions Pertaining to Gender 1.What proportion are male and female? 2.Do they change sex as they age? 3.Are male trees bigger than female trees? 4.On a hermaphrodite, do male flowers appear earlier than female to prevent self pollination? 5.Do female trees show a higher degree of forking? 6.How much seed does a true hermaphrodite produce?

Flower Ratios Recorded at the Scarr BSO in 2002 and trees trees

Gender Answers Average height of all females = 414cm Average height of all males = 410cm Male flowers appear up to one month earlier than female flowers preventing self fertilisation Average forks per female tree = 0.97 Average forks per male tree = 0.80 Huge variation in seed production by hermaphrodites