How hybrid plant varieties can address food security and climate change

Hybrid crops and horticultural crops can play an important role in supporting global food security. They give higher yields and are often more resistant to disease and climate stress than non-hybrid varieties. But for many crops there are no hybrid varieties. Why is that?

Maize is a very important crop in the world, and the use of hybrid varieties is common. The first type was introduced in 1930. But this has not happened with other major crops such as wheat and cassava. Now, for the first time, a comprehensive study of all the factors that determine whether commercial breeders can come up with a hybrid variety. Sometimes biological problems arise. often economic factors join the game.

This is a unique comprehensive survey published in the journal Nature Plants. The authors of the article are associated with the company for the cultivation of potato hybrids Solynta and Wageningen University & Research. The main author is Emily ter Stig, Ph.D. PhD in Development Economics.

Creating inbred lines

The hybrid variety is “a descendant of two parent plants that complement each other perfectly. Then the hybrid combines the best qualities of the parents, ”says Ter Stig. But to create suitable parents you need to make sure that they are as genetically homogeneous (homozygous). You can do this by crossing your parents with yourself – a process called “self-eating” or “inbreeding”. “Developing strong parenting lines takes time and costs money. Therefore, the breeder must be sure that he will get a return on these investments, ”says Ter Stig.

There are many obstacles that need to be overcome. First of all, it must be biologically possible to obtain these homozygous parental lines. Ideal for self-pollinating plants, while plants that are always cross-pollinated with another plant, much harder. Moreover, some cultures also have multiple sets of chromosomes, making it even more difficult or nearly impossible to create inbred parental lines.

Potatoes grown in our fields, for example, have four sets of chromosomes with hereditary material. This is an important reason why there have been so few attempts to generate native lines. This makes breeding potatoes especially difficult, and so we still have ancient varieties such as Bintje or Russet Burbank.

But we are making progress. In fact, there is a diploid potato that has only one set of genes. These varieties did not support inbreeding. But scientists from Solynta and Wageningen University & Research have recently managed to get around this hurdle. The key to this is the Sli gene. Now it is clear the way to grow potatoes from hybrid seeds, not from tubers.

Economic drivers

“There is another issue to consider with wheat. Wheat yields relatively few seeds per pollination, and the added value of hybrid varieties is still limited. It is also a segmented market. Therefore, developing hybrid wheat is not yet cost-effective for breeders,” said Ter Stig.

Scientists have studied economic factors to develop a hybrid variety. On the one hand, this is the cost of the development process, and on the other – the expected revenue. Both play an important role. “Large markets or high value-added markets are more profitable for breeders. That’s why you see hybrids of major world crops and important vegetables, but less for small local crops. In addition, the market price of harvested products determines how much the grower is willing to invest in seeds. market prices for growers affect the cost of seeds and breeders ’incomes”.

By joint efforts

High-yielding and strong crops are urgently needed to address global food security and climate change. “But there is no progress in the selection of some major crops that are important for food security. This applies to cassava, sugar cane and sweet potatoes, but also to traditional leafy vegetables and fruits. If we want to improve and provide access to nutritious food in poorer countries“It’s important to make progress in less commercially attractive cultures as well,” says Ter Stig.

The authors of Art Nature Plants The article recommends public-private partnership in cases where breeders do not see immediate business. Examples of this approach are the national program Topsectorenonderzoek (Top Sector Research) and its predecessor Technologisch Top Institute Green Gronetics (Technologisch Top Institute Green Genetics). another, which was then used by breeding companies to breed new disease-resistant varieties ”.