Lettuce was first cultivated in the Caucasus six thousand years ago. Later, in the Middle East, then in Egypt, then in ancient Greece and Italy, in Central Europe, and finally in North America, the main varieties arose by abduction and selection.
Chinese and Wageningen researchers are writing this week In Natural genetics. They studied the genetic variation of 445 varieties of greens from 47 countries. They associated groups of genes with certain traits. That information will help modern farmers improve their crops.
Wageningen Genetic Bank
There are hundreds of varieties of lettuce today, ranging from avocado and oak leaf lettuce to glacial lettuce and romaine. They all belong to the same plant species, Lactuca sativa, Which originated from the wild lettuce variety L. Seriola. But it is not yet clear where, when or how the process began. Genetic resources as part of the University of Wageningen and research Researchers line plant products from the Genetic Bank of the Netherlands (CGN). It stores more than 23,000 seed samples from thirty different crops, in addition to farm animals, trees and shrubs.
“Research on wild relatives of agricultural species is very important,” says CBN researcher and one of the authors of the article, Rob van Durren. Natural genetics. During the cultivation process, a very strong selection was made for desirable characteristics such as taste and simplicity of cultivation. But a lot of genetic differences have been lost in this process. “Thus strong traits and resistance to certain diseases are important traits for farmers. These can be brought back into the crop by crossing, but you must first find those properties. “The wild species create an enormous reservoir for this,” says Van Durren.
Sometimes CGN scientists go out to collect wild crops: lettuce from Tajikistan, melon seeds from Uzbekistan, leeks from Greece, lettuce from Jordan. But for the study of lettuce Natural genetics They do not have to leave the house. “We have a unique collection at Wageningen,” says Van Durren, “which again proves its worth”.
Four years ago Lettuce has been fully genetically mapped for the first time. The result is called the reference gene: a map of the genes of spinach. “Thanks to that reference gene, we were able to sort those 445 species relatively easily,” says Van Truran. “We looked for variations: places where the genetic reference of that type deviates from the gene.”
The first natural feature was already lost in the Caucasus
The variation listed tells about the relationship with the wild ancestor – and the time elapsed since the family tree split. “For example, we now know that the first natural feature in the Caucasus has already been lost,” says Van Truran. “That is, the ability of the plant to scatter the seed in the wind, like the corresponding dandelion. The seeds in the plant are easy to collect.” Somewhere on the road to Egypt the vertebrae were lost in the leaves.
“We discovered many new connections between clusters of genes and certain traits,” the Wageningen researcher continues. “We want to further investigate those relationships. We want to see if there are clear genetic markers for those traits that farmers can use. Such markers will greatly speed up reproduction.”
The good thing about the new study, Van Durren insists, is that the data is available for free. Can be used by anyone for research and crop development. “Thanks to this sequence of data, other users can learn very quickly about the properties of genetically engineered products,” says Van Truran. “It’s like we found the key to a treasure chest.”
A version of this article appeared in the April 15, 2021 issue of NRC Handelspot
A version of this article was also published in the NRC on the morning of April 15, 2021