1. Propagating Cynthiana/Norton Grapes
Basic Overview and MTSU Research Update
Tony V. Johnston, PhD, CFS, MS, MPH
Professor
School of Agribusiness and Agriscience
Middle Tennessee State University

2. Overview Propagation Basics Dormant (Hardwood) Propagation
Softwood Tip Propagation
Bench Grafting
Tissue Culture
From the Greenhouse to the Vineyard
Hardwood Propagation Issues
Propagate or Not?
MTSU Research Updates
Endophytes and their Impacts
Current and Future MTSU Research Goals
Research Credits
Questions

3. Propagation Basics
Always use clean, sharp knife and sterile rooting medium (no fertilizer)
Never use pruning shears or knife used to cut other plants without prior sterilization
Can transfer infectious viruses, mold, etc.
High humidity environment is essential (no roots!)
75oF minimum temp at all times
Good light– use a grow light if necessary

4. Dormant (Hardwood) Propagation
Traditional method
Pencil diameter, ft long
Must be viable wood (green pith)
Collect after vines are completely dormant
Remove all shoots and leaves
Set in sand, vermiculite/soil, or potting soil
Largest diameter end down; dip in rooting hormone (e.g. Roottone® or Hormonex®)
Constant temperature above 60oF

5. Softwood Tip Propagation
Collect cuttings anytime during growing season
Cut 3-4 inches from growing tip end
Strip all but 3-4 leaves on growing end of shoot
Dip end in rooting hormone (e.g. Roottone® or Hormonex®)
Place in sterile sand, vermiculite or peat moss
Keep moist but not soaking
Minimum temp 72oF; warmer better

6. Bench Grafting (pt. 1) Dormant propagation technique
Not widely employed at home
Essential for protection of non-phylloxera resistant varieties of grapes
Must have rootstock and scion
Both rootstock and scion must be very similar in diameter

7. Bench Grafting (pt. 2)
Both rootstock and scion are cut in identical ways (slant or z)
With machine, omega cut can be made
Join at cut, aligning carefully
Wrap union with grafting tape and allow to heal
Transfer to ground after viability is established
Do not remove grafting tape!

8. Tissue Culture (pt 1) Definitely not a home-based technique
Sterile environment and technique essential
Plant cells are extracted from carefully washed and sterilized plant parts (leaf, stem or root)
Place cells on specialized growth medium
Cells grow into undifferentiated (non-specialized) “callus”

9. Tissue Culture (pt. 2)
Callus is then transferred to different medium and conditions adjusted to stimulate the development of roots and stems
Hormone and medium composition is different for almost all plants
End result is a true clone– an exact replica of the source cells

10. Greenhouse/Lab to Vineyard
Propagated vines should be planted outdoors ASAP
Vines don’t do well in a greenhouse environment
Best to plant in spring after last frost
Two to three years to first harvest

11. Cynthiana/Norton Hardwood Propagation Issue
20 – 40% success rates typical
Success = viable plant
Common result: leaf production without root development
Must compensate by trying to root hundreds to get tens of successes
Time and resource intensive with low return on investment

12. Propagate or Not? Commercial plants are available to purchase
Best to purchase from nurseries “close” to Tennessee
If you have a “facility” in which to grow out your cuttings, home propagation is inexpensive, albeit time consuming and inefficient
Can be significantly more cost effective than purchasing vines from a nursery

13. MTSU Research Update
Focused on finding ways to better propagate Cynthiana/Norton grapes
Both hardwood and tissue culture techniques being studied
A follow-on to research conducted in Honduras
Enormous difficulty in rooting dormant vines
Complete failure of tissue culture efforts due to mold growth on plates

14. MTSU Hardwood Propagation Research
Evaluating:
Timing of hardwood collection (12 month project)
Efficacy of rooting hormone use
Timing of planting of hardwood propagated plants in the vineyard
Is dogma correct?

15. MTSU Tissue Culture Research
Initial attempts to culture Cynthiana/Norton grapes totally unsuccessful
100% failure to stimulate mold-free callus formation
While using different antifungal compounds and trying different pre-sampling techniques discovered an endophyte in the vines

16. What is an Endophyte?
Organisms, often fungi and bacteria, that live between living plant cells
Relationship with the plant varies from symbiotic to bordering on pathogenic
Extremely unusual and valuable organic substances are produced that may assist in helping solve not only human health, but plant and animal health problems
From

17. Endophyte Impact
Being a mold and living between the cells, it always contaminates tissue culture medium
Must eliminate endophyte to allow for tissue culture
Role of endophyte in Cynthiana/Norton grapes unclear
May play a role in the difficulty to propagate via hardwood culturing

18. Current MTSU Research Outcomes and Focus
MTSU research has resulted in technique to eliminate endophyte without killing plant tissue
Now researching techniques to take endophyte free tissue to plantlet development
Looking to create line of endophyte free plants

19. Future MTSU Research Focus on
Exploration of role of endophyte in Cynthiana/Norton grapevines
Determine whether endophyte-free Cynthiana/Norton are viable and can remain endophyte-free once planted
Determine productivity of potentially endophyte-free Cynthiana/Norton
Determine quality of fruit produced by potentially endophyte-free Cynthiana/Norton
Identify Cynthiana/Norton endophyte

20. Research Credits Dr. John DuBois, MTSU Biology Professor
Mr. Shannon Smith, MTSU Biology Graduate Student
Ms. Amanda Leachman, MTSU Biology Undergraduate Student
Ms. Aimee Wilson, MTSU Biology Undergraduate Student

21. Questions?