Genetic improvement of ash in British forestry: Floral Diversity of Ash- Fraxinus excelsior

1. Genetic improvement of ash in British forestry:Floral Diversity of Ash-Fraxinus excelsior Jo Clark National School of Forestry University of Central Lancashire joruthclark@hotmail.com

2. 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

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

4. BIHIP – The British and Irish Hardwood Improvement Programme • 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)

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

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

7. Plus Tree Selection

8. 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

9. BSO Assessment:Form Major Kink Severe Sweeps Perfect Tree Classic Fork

10. Mean Height of Families Recorded at Four BSOs in 2001

11. Family Performance for Height

12. 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?

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

14. Floral Biology of Ash • Wind pollination • A polymorphous species exhibiting a continuum of gender Staminate flowers Pistillate flowers

15. True Hermaphrodite

16. Hermaphrodite Flowers Stigma Style Anther Filament

17. Predominantly hermaphrodite flowers with some pure male inflorescences

18. Predominantly Male Flowers

19. Predominantly Female Flowers

20. Male Inflorescence With the Terminal Flower Female

21. Seed Development

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

23. Flower Ratios Recorded at the Scarr BSO in 2002 and 2003 2002 170 trees 2003 589 trees

24. 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