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

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

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

Dormant (Hardwood) Propagation Traditional method Pencil diameter, 1-1.5 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

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

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

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!

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”

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

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

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

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

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

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?

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

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 http://plantsciences.montana.edu/facultyorstaff/faculty/strobel/endophytes.html

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

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

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

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

Questions?