How Syngenta Breeds Resistance Traits in Vegetable Crops
Damage to crops from diseases and pests leads to yield loss and increased production costs for growers. Largescale disease or pest issues could also affect global food security. Breeding pest resistance into the genetics of plants is an effective way to manage vegetables and to protect crops and the food supply. In vegetable seeds, our researchers use conventional breeding methods to find resistances to diseases and pests.
Breeding selection has been a practice in agriculture for thousands of years. It ensures the most desirable crop traits are passed down season after season. Early agrarians selected plants for qualities like taste and seed size. Now, with technology and data, plant breeding scientists do the same thing for vital traits like resistance to diseases and pests. Resistance breeding is one of many ways scientists at Syngenta Vegetable Seeds look to meet the needs of growers today and in the future.
“At Syngenta we are working on our new generations of resistance to provide a long-term solution for the future,” said Eleni Bachlava, Head of Applied Data Science at Syngenta Vegetable Seeds.
In today’s breeding, scientists find cultivars or accessions that are resistant to disease or pest damage. Then, they search for the gene, or genes, with the resistance needed. Introgression, which is carried out through the process of hybridization and repeated backcrossing, transfers desirable traits.
Plant breeders develop molecular markers to follow the resistant gene through the process. Molecular markers are similar to using a map to navigate an unfamiliar city, according to the Crop Science Society of America. It eliminates guesswork as breeders can confirm the presence of the necessary gene.
Resistance Breeding in Brassicas
Brassica trait conversion at Syngenta Vegetable Seeds is one example of how modern resistance breeding can bring solutions to growers faster than ever. Typically, the conversion to add traits to a parent line requires repeated cycles, or generations, of selective backcrossing. Backcrossing allows breeders to transfer a desirable trait from one variety into a desirable background of another. Backcrossing typically takes six to seven years. However, at Syngenta Vegetable Seeds, that cycle is reduced to just three to four years through genotyping.
Bringing together experts and world-class facilities at Syngenta Technology Centers, innovations in brassica products are developed using the latest technology and traditional breeding methods. During the development of brassica lines, plants are brought to flowering based on pre-selected traits using genetic markers and field performance data. This allows breeders to analyze progeny that are most similar to the parent for subsequent backcrosses to speed up the process.
This is all part of the resistance breeding phases all new varieties go through at Syngenta Vegetable Seeds. From screening to deployment, the time needed to reach commercialization varies by complexity of the trait and crop, about five to 15 years.
Years 1-5: Screening
Resistance breeding process starts with screening. First, teams work to determine if a particular outcome is possible. They determine the complexity of finding resistance and how much growers in the future may need certain resistances in their crops.
Pathogens and insects are collected and multiplied in facilities. During this time, scientists also develop screening tests. Finally, they collect and screen for germplasm variation.
Years 4-6: Trait Fixation
After the screening stage, plant breeders select the best performing material from the screening stage. By carefully selecting the plants that exhibit natural resistance to the specific diseases screened, these plants can be crossed with others to create offspring with enhanced resistance.
Years 5-9: Discovery
“We are looking for which species are resistant and how the resistance is working,” said Marc Bots, Syngenta Head of Vegetable Trait Development. “Is it dominant? Is it recessive? How many genes are involved?”
During the discovery phase, scientists aim to answer those questions. They develop the discovery population of plants to create markers. During this time, they look at phenotyping, which is the plant’s observable characteristics that are a result of the interaction between the plant’s genetic background, or genotype, and the environment in which it was grown.
Years 8-9: Validation
“Once we have the genes and resistance available, we make one line resistant and then we test in different environments,” explained Martina Gunneman, Syngenta Head of Germplasm Development for Lettuce and Brassicas. “Normally in different locations where the disease pressure is present and also in our Technology Center.”
In locations like the Seed Innovation Center in the Netherlands, plant breeders recreate conditions from a variety of countries to validate the resistance in different growing environments. By testing in these conditions, breeders can ensure resistance in various hot-spot locations for any disease.
Year 8-14: Deployment
Once results are validated, the resistant variety moves into deployment. Breeders take the most promising gene, or genes, and introgress them into the most advanced parent lines available. This gives growers access to the latest varieties with the top yield potential and the resistance they need.
Breeding for the Future of Farming
For the thousands of years that humans have been farming, the goal has been to improve yields and practices. At Syngenta Technology Centers, scientists are continuing this tradition with more efficient and precise methods. Using the latest data and technology, breeders in Syngenta facilities intensively screen germplasms for resistances. Technical research allows for the highest degree of repeatability and control. Specialized growth chambers in Syngenta facilities allow breeders to replicate the conditions they are testing year-round, ensuring consistent results.
The resistant varieties in fields today are the result of 10 to 20 years of screening, testing, and validation. Right now, Syngenta Vegetable Seeds breeders are working to predict the challenges facing tomorrow’s growers and looking at thousands of potential products to help meet those needs. While the obstacles future growers will face can be difficult to predict, one thing is certain: through traditional breeding techniques and modern technology, vital products with natural resistance to threats will make it into the hands of growers to help them tackle each challenge.
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