Grains grow more erratically in drought

Cereals adapt to drought. How does that affect their yield?

'How grains grow depends on a number of choices in the plant. The wheat or barley plant can produce many or few lateral shoots (branches with spikes, ed.), many or few seeds, large or small seeds. In addition, the timing of the plant's development matters a lot; do we see early or late flowering? These options all affect how much yield comes from a plant.

In drought, the choices a plant makes in this regard are under a lot of pressure. Drought costs a lot of energy and then it doesn't manage to invest in everything. So the yield goes down - as we see in Africa but also Europe, among others. But what choices plants make in this can make a lot of difference.'

And you are looking for the best possible outcome?

'That's the ultimate goal. Sometimes you see more side shoots, but then there are fewer seeds on a spike, for example, or there are a lot of seeds on a spike, but the seeds are smaller. Among those different options, there is going to be an optimum, with the most production. Sometimes only a very small percentage more yield is involved, but calculated over an entire field, that is still a lot of grains.

What the desired optimum is also depends on the context: the field, the variation in weather conditions that occur, and the climate. For example, do you want early bloomers or late bloomers? That depends on how and where the plants grow. Rapid flowering can be a good strategy in a climate where drought often occurs later in the season. Even if it might give a lower yield, it is still better than no yield at all.

How will your research contribute to drought-resistant grains?

‘It often happens that breeders combine a range of favourable genes in a new variety, but the intended trait is still not observed in the plant. I hope that my research and that of my team will help us understand these genes and their interactions even better. Without a deep understanding of gene interactions, the impact of favourable genes is almost impossible to predict. Moreover, if you map the genes for a particular trait even more precisely, you can proceed more quickly with breeding for different situations, such as a rapidly changing climate.’

A different variety for every situation within each crop?

‘Various circumstances come together everywhere. That is quite a challenge, but I believe it should certainly be possible from the plants' perspective. The necessary variation is already present in the plants; it is just a matter of getting the right combinations of genes together.’

And what about relocating crop cultivation? For instance, can’t we just start growing Southern European varieties and crops in Western Europe?

‘I get that question quite often. It seems logical, given the shifting climate. But besides a difference in climate, there is also a difference in day length. The day length in Spain is shorter in spring and summer than in the Netherlands. Crops are adapted to those specific conditions and do not achieve optimal yield outside of them.’