Researchers studying diseases of the world’s most beloved fruit vegetable meet to grapple with climate change as a driving force affecting production of this popular crop

The latest advances in research on diseases of the world’s most popular fruit vegetable were shared at the VI International Symposium on Tomato Diseases, a major conference that attracted more than 200 experts, scholars, researchers and students from 25 countries to Taichung, Taiwan to discuss ways to address the challenges diseases present to production of this globally important vegetable crop.

Organized by the World Vegetable Center, the Taiwan Agricultural Research Institute (TARI) and National Chung Hsing University (NCHU), the event was held at the NCHU Conference Center from 6-9 May 2019.

The symposium was opened by NCHU President Shieu Fu-shen; WorldVeg Director General Dr. Marco Wopereis; International Society for Horticultural Science (ISHS) Representative & Chair, Tomato Diseases Working Group Dr. Enrique Moriones; Director of Science and Technology, Council of Agriculture (COA), Taiwan Dr. Dennis Wang; and Acting Director, Taiwan Agricultural Research Institute (TARI) Dr. Jyh-Rong Tsay.

The symposium theme, “Managing Tomato Diseases in the Face of Globalization and Climate Change” explored the effect of climate on one of horticulture’s most advanced, globalized, and innovative sectors.

Annual production of tomato has increased by 300% over the past 40 years. Yet higher temperatures, heat waves and longer droughts, change in precipitation patterns, more frequent wildfires, and an increase in the number, duration, and intensity of tropical storms are fostering the development and spread of tomato diseases and altering pest behavior and distribution.

And, although international commerce brings prosperity, it also transports horticultural pests and diseases around the globe, including begomoviruses and emerging Crinivirus, bacterial wilt and bacterial spot, late blight and early blight, and Fusarium wilt.

In his opening remarks, Dr. Wopereis observed that we know very little about the effect of rising CO₂ levels and temperatures on disease infestation levels in open field tomato production. The concentration of CO₂ has risen to 410 ppm, and it may well become 800-900 ppm near the end of this century. How will tomato pathogens behave under high temperatures and CO₂ levels? What about insects, as they often serve as a vector for disease?

“We need to think of smart and affordable experimental set-ups and surveys to test how crops like tomato grown under open field conditions respond to insect and disease pressure under a range of future climate conditions,” Wopereis said. “Next, we need to try to track down genes that can resist the diseases predicted to become more severe in the future.”

Dr. Wopereis noted that breeding for resistance to diseases in tomatoes was high on the symposium agenda, and with good reason. “Improved varieties will have a large influence on productivity and profitability,” he said.

He touched on the importance of the formal seed sector in scaling improved tomato breeding lines, using India’s vegetable seed sector as an example. Until 1988, the Government of India restricted the import of vegetable seed and the informal seed sector dominated, leading to inconsistent seed supply and quality. Liberalization of the seed sector and stronger protection of breeders’ rights gave an enormous boost to private seed sector development and the vegetable seed sector in particular. Quality vegetable seeds are now available across the country.

Keynote speakers included Dr. William Fry, Cornell University; Dr. David Francis, The Ohio State University; Dr. Nemo Peeters, INRA, France; Dr. Moshe Lapidot, Volcani Institute, Israel; Dr. Kai-Shu Ling, US Department of Agriculture; and Prof. Shyi-Dong Yeh, NCHU Advanced Plant Biotechnology Center. WorldVeg Virologist Dr. Lawrence Kenyon chaired the symposium scientific committee.

Papers were presented on genetics and breeding for resistance, alternative approaches for resistance, managing bacterial diseases, and virus and viroid management.

Field trips on May 9 visited the Taiwan Agricultural Research Institute and the World Vegetable Center.

The symposium was held under the auspices of the International Society for Horticultural Science (ISHS). Taiwan’s Council of Agriculture (COA) and Ministry of Science and Technology (MOST) provided financial support for the event, along with sponsors CropLife Taiwan, Known-You Seed Co., Genmail Biotechnology Co. Ltd., Advanced Green Biotechnology Inc., ID Lab Co., Ltd., and Lead-Biotech Instruments Co.

Photos: Lawrence Kenyon and Peggy Pei-chi Wang