Features Production Research
Grafting tomatoes brings better yields

December
2, 2011 – New research shows that tomato growers may not have to choose between
plant varieties that produce high-value fruit and those that are resistant to troublesome
soil-borne pathogens. Researchers and farmers alike are demonstrating that
grafting shoots of one plant to the root system of another is a cost-effective,
environmentally sound way for growers to both manage diseases and cash in on
improved yields.

December
2, 2011 – New research shows that tomato growers may not have to choose between
plant varieties that produce high-value fruit and those that are resistant to troublesome
soil-borne pathogens. Researchers and farmers alike are demonstrating that
grafting shoots of one plant to the root system of another is a cost-effective,
environmentally sound way for growers to both manage diseases and cash in on
improved yields.

One
Pennsylvania farmer growing grafted tomatoes in high tunnels boosted his yields
20 per cent – or $9,024 per high-tunnel acre – compared to his standard
practices. Separately, North Carolina State University researchers determined
that grafting with organic and heirloom tomatoes can increase profit by 38
cents per plant. 

Sustainable
Agriculture Research and Education (SARE) recently released a new fact sheet – Tomato Grafting for Disease Resistance
and Increased Productivity – that helps farmers and agricultural
educators learn how to graft tomatoes to fight disease and improve the health
and vigour of tomato crops. It is available for free download from SARE’s Learning Center.

Growers
interested in experimenting with this novel approach of improving resistance to
soil-borne pathogens will find:

• Helpful tips for grafting plants,
  including variety selection based on resistance to particular diseases,
  step-by-step grafting techniques and caring for grafted plants
• Instructions for building a
  healing chamber for newly grafted plants, and for transplanting them to the
  field
• An analysis of the economic
  viability of grafting under different conditions.

Still
a relatively uncommon practice, researchers around the world have demonstrated
that grafting can protect plants against a variety of soil-borne fungal,
bacterial, viral and nematode diseases, such as Verticillium and Fusarium wilt
(FW), corky root rot, root-knot nematodes, bacterial wilt, southern blight and
other diseases.

Grafting
is on the rise since it has been shown to successfully manage bacterial wilt in
tomatoes, even in severely infested soils. In western North Carolina, a
resistant rootstock was used to reduce bacterial wilt in tomatoes: At season’s
end, nearly 90 per cent of the control plants died while 100 per cent of the
grafted plants not only survived, their yield was more than two fold that of
the surviving non-grafted plants.

Tomato
grafting shows particular promise for high-tunnel, heirloom and organic
growers. With little opportunity for extended crop rotation intervals in a high
tunnel, disease pressure can be very high. Heirloom varieties are not bred for
resistance, and, in organic systems, other disease management practices are
limited. Due to the phase-out of methyl bromide, grafting could become a
widespread pest management strategy for a large segment of growers.

Interested
in sustainable pest management? Visit the pest management section
of SARE’s Learning Center to see itsentire collection of free resources related
to this topic.