Pea and Lentils Invest in Root System Development Differently

By Adityarup Chakravorty

Underneath the surface, plant roots are hard at work. Roots, of course, are how plants get water and minerals from the soil. But digging into how different root systems affect crop yields has been challenging for researchers.

"We know so much less about root traits and how they impact crop yields compared to leaf characteristics," says Maryse Bourgault, a researcher at the University of Saskatchewan, Canada.

Bourgault is the lead author of a new study in which researchers unearth links between root systems and yield in lentil and pea crops grown in semi-arid areas. This study was published in The Plant Phenome Journal, a publication of the Crop Science Society of America.

A large percentage of global lentil exports originate in the Northern Great Plains in the United States and Canada. In these semi-arid areas, almost 4.5 million hectares—more area than the state of Maryland—are used to grow pea and lentil crops.

Bourgault and colleagues found that the highest yielding pea and lentil varieties had quite different root system structures.

In lentils, big root systems were well correlated with high yields. "Lentil plants tend to be small. So, breeders have been trying to get them to be bigger and taller," says Bourgault. "If we are pushing for bigger lentil plants, we should also select for bigger lentil root systems."

In peas, the situation was more complex. The highest yielding pea varieties tended to have root systems that were average in size.

"We think that root growth in peas may be more about timing during the plants' growing season," says Bourgault. The researchers think that the majority of root growth needs to happen before pea plants flower. "Once flowering happens, all the energy from photosynthesis needs to go to the pea pod development rather than the root growth."