They couldn’t meet in person, but that didn’t stop members of the APSA-WorldVeg Vegetable Breeding Consortium from gathering—virtually—to share progress and explore opportunities ahead for the vegetable seed sector in Asia.

Plant breeders are no strangers to viruses; some will spend their entire careers seeking to develop vegetable varieties with resistance to the infectious pathogens. So it was no surprise that the Asia & Pacific Seed Association (APSA)-World Vegetable Center Vegetable Breeding Consortium was not to be daunted by SARS-CoV-2.

Faced with a patchwork of travel restrictions and quarantines, the consortium decided to transform this year’s annual workshop into a videoconference.

On 12 May 2020, nearly 200 participants from 33 companies and WorldVeg met online for discussions and intensive seminars on the Center’s breeding work and other research. The video event was the fourth edition of the annual workshop.

“I am certain that after this pandemic is behind us the world will pay much greater attention to nutrient-dense crops and vegetables in particular, and how they fit into food systems, from seed to plate,” said WorldVeg Director General Marco Wopereis in his opening remarks. “The work we do together in this Consortium − producing high quality, sturdy and nutritious vegetable seeds − is a critical entry point towards future food systems that are more resilient to shocks and provide healthy diets for all.”

Kanokwan (May) Chodchoey, APSA Executive Director, noted how APSA member companies benefit from WorldVeg breeding programs, innovation and knowledge, and encouraged members to learn from WorldVeg and each other, and share their comments on issues of interest to develop meaningful programs and activities for future meetings.

“Nutrition and food security is important now more than ever,” she said, “and vegetable breeding and seed is very important for supply chains and food security, even without COVID-19.”

Seed companies participating in the consortium get early access to new breeding lines and the opportunity to interact with WorldVeg experts on upstream research. In return, WorldVeg receives feedback about the performance of its material in various locations and in commercial seed production—vital information that can help WorldVeg demonstrate its value to donors.

Farmers—seed company customers—benefit most of all: they have access to more and better quality vegetable varieties to produce on their farms.

— Read more about consortium membership —

Vegetable breeding update

Session I focused on vegetable breeding, moderated by Roland Schafleitner, WorldVeg Flagship Leader for Vegetable Diversity and Improvement.

Tomato

Global Plant Breeding Lead Scientist Peter Hanson updated the group on WorldVeg tomato breeding programs and progress on insect resistance. “Resistance is a must-have trait for open field production,” Peter said. “We’re introducing lines with multiple Ty genes with resistance to begomoviruses.” The WorldVeg tomato yellow leaf curl disease (TYLCD) breeding strategy includes two elements: pyramiding multiple Ty genes to improve the range and level of virus resistance, and incorporation of vector resistance from wild tomato species.

Among other activities, the tomato breeding group is studying acyl sugar levels in tomato plants that repel whiteflies, a major vector of tomato viruses and diseases. Mapping heat tolerance in populations with good horticultural traits has revealed the unusual qualities of ‘Siberia,’ a tomato variety that demonstrates both heat and cold tolerance. It may prove useful as breeding stock.

Flavonoids, such as anthocyanins and carotenoids, are compounds linked to improved plant tolerance to abiotic and biotic stresses. Human diets high in flavonoids are associated with lower risks of some cancers and heart disease. Peter presented two high anthocyanin and high carotenoid lines with dark purple skin color and red internal color.

Peppers

Vegetable Breeder – Pepper Derek Barchenger briefed consortium members on pepper breeding activities. “About 65% of the world’s peppers are produced in Asia,” Derek said. “We’re focusing on breeding chili and sweet pepper with tolerance and resistance to key diseases and stresses.” He explained recent work on a heat tolerance protocol using an impedance flow cytometer to measure pepper pollen grain numbers and activity under high heat conditions, and showed a short video to demonstrate how quickly the device measures grain numbers and germination rates. “There’s considerable variability in the pollen numbers in WorldVeg pepper accessions,” he said.  “Pollen number is an important factor to monitor in heat stress, as accessions with more pollen are more likely to set flowers.”

Derek presented WorldVeg studies on anthracnose resistance, which have identified a stable source of resistance in C. baccatum. He then reviewed the latest pepper offerings for consortium members: high yielding chili pepper with diverse fruit shapes and sizes for good performance in hot weather, with resistance to Chili veinal mottle virus (ChiVMV), Potato virus Y (PVY), Phytophthora capsici race 3, and anthracnose. Sweet pepper lines on offer combine resistance to ChiVMV, PVY, P. capsici race 1, and bacterial spot (Xanthomonas campestris). WorldVeg will also release newly developed genic male sterile (GMS) chili and sweet pepper lines with WorldVeg-developed molecular markers linked to sterility, as well as three new cytoplasmic male sterile (CMS) sweet pepper A- and B-line pairs. GMS and CMS lines are used for efficient and cost-effective hybrid seed production. The new male sterile lines combine resistance to PVY and moderate resistance to P. capsici race 1 and have high yield during the hot season.

Cucurbits

Next up was Narinder Dhillion, Vegetable Breeder – Cucurbits and Manager, WorldVeg East and Southeast Asia Kamphaeng Saen Research Station in Thailand. WorldVeg’s cucurbit breeding program focuses on four cucurbit species: bitter gourd (Momordica charantia), tropical pumpkin (Cucurbita moschata), ridge gourd (Luffa acutangula), and sponge gourd (Luffa aegyptiaca = cylindrica). Cucurbit cultivars should withstand the onslaught of viruses such as Tomato leaf curl New Delhi virus (ToLCNDV) in bitter gourd, ridge gourd and sponge gourd, and Squash leaf curl virus along with ToLCNDV in pumpkins. Narinder reviewed the progress achieved in breeding improved lines for each crop.

Cucurbit powdery mildew (CPM) caused by Podosphaera xanthii is another serious economic disease of bitter gourd; five new bitter gourd inbred lines resistant to CPM developed at WorldVeg will be made available to consortium members. “WorldVeg has established a bitter gourd support group for private seed companies and the members are developing elite bitter gourd F1 hybrids using WorldVeg bitter gourd materials,” he said. “It’s a unique public-private cooperation.” WorldVeg’s pumpkin breeding effort has resulted in the development of begomovirus-resistant pumpkin. WorldVeg Luffa breeding activities are based on a diverse genepool of landraces collected from various countries across Asia to develop genetically diverse and improved products in popular market segments.

WorldVeg Director General Marco Wopereis prepares to address his remarks to the camera.

Special projects

During Session II, workshop participants explored future research topics and ways to apply new breeding technologies to advance the development of improved varieties. Ideas for multilateral project funding were presented for discussion and review among consortium members.

Peter Hanson discussed opportunities for consortium members to test their vegetable varieties in different climates and agronomic conditions in Africa and to build networks with African seed companies. “There’s a lack of improved, tropically adapted vegetable varieties in Africa,” Peter said. “It’s likely that some APSA members have hybrids that could perform well in Africa with local adaptation.” WorldVeg proposes running impartial variety trials to test performance in Benin and Tanzania. “Benin is an excellent country for testing, as it covers numerous agroecological zones – coastal, sub-humid, semi-arid,” he said. “Tanzania has highland vegetable production areas.” Tomato, chili and sweet pepper, and onion are the suggested crops.

Derek Barchenger elaborated on developing heat stress tolerance of tomato and peppers. “People living in tropical and subtropical countries will be much more affected by climate change,” he said. “These countries have more smallholder farmers—they need heat-tolerant varieties.” He encouraged consortium members to support joint research activities to study and develop pepper lines for high fruit set under high temperatures.

Genebank Manager Maarten van Zonneveld emphasized the need to collect and safeguard cucurbit diversity in south and southeast Asia. He proposed a three-phase project to rescue landraces of bitter gourd, luffa, and pumpkin in Myanmar, Bangladesh, and Vietnam. This would result in a unique set of at least 630 accessions of cucurbit landraces and wild varieties, augmented by the collection of novel information about genetic diversity and variation in agro-morphological traits of these crops. APSA members, participating national genebanks, WorldVeg, and ultimately farmers would benefit from this increase in germplasm and knowledge. “There’s a need for better collaboration between the public and private sector in germplasm collection,” Maarten said. “And there is much diversity to collect before it is lost forever.”

Flagship leader for Vegetable Diversity and Improvement Roland Schafleitner wrapped-up the discussion. “I miss the personal interaction of the workshop,” Roland said. “But this meeting has shown that there is a way to work together despite the pandemic. And of course it is always possible to contact WorldVeg staff to keep in touch. I’m thankful we had the opportunity to talk today.”

In closing, Marco Wopereis expressed his appreciation to the participants for a brisk and engaging workshop. “It has been an intensive and high-speed event,” he said. “I learned a lot, and I hope it was the same for you. I really liked that high speed question-and-answer — we exchanged a lot of knowledge in the past couple of hours!”

Marco thanked May Chodchoey and the APSA and WorldVeg teams that coordinated the online workshop: “The organization was flawless,” he said. “Thanks to all the participants for a very rich debate. Stay safe everyone!”

Story and photos: Maureen Mecozzi