Plant roots are actively working below the surface. Plants naturally obtain water and minerals from the soil through their roots. However, it has been difficult for researchers to delve into how various root systems effect crop production. According to Maryse Bourgault, a researcher at the University of Saskatchewan in Canada, “we know so much less about root qualities and how they affect crop yields compared to leaf attributes.” In a recent study, Bourgault served as the lead author. The researchers discovered relationships between root systems and yield in lentil and pea crops produced in semi-arid regions. The Crop Science Society of America’s magazine Plant Phenome Journal published this work. The Northern Great Plains of the United States and Canada account for a sizable portion of the world’s lentil exports. Nearly 4.5 million hectares, or an area larger than the state of Maryland, are utilized to cultivate pea and lentil crops in these semi-arid regions. Bourgault and colleagues discovered that the pea and lentil varieties with the highest yields had very distinct root system morphologies. Large root systems and high yields were positively associated in lentils. “Lentil plants are often tiny. Breeders have therefore been working to make them bigger and taller, according to Bourgault. “If we are promoting larger lentil plants, then our breeding initiatives should likewise prioritize larger lentil root systems.”
The circumstance in peas was more complicated. The root systems of the pea types with the highest yields tended to be average in size. According to Bourgault, “We believe that timing during the plant’s growing season may be more important for pea root growth.” The majority of root growth, according to the researchers, must take place prior to pea plants flowering. “Once blooming occurs, the pea pod development must get all the energy from photosynthesis instead of the root growth.” The discovery that various root systems would result in higher yields in various crops went slightly against the expected trend. The general consensus was that all crops in semi-arid regions would benefit most from having “deep but lean” root systems.
According to Bourgault, “the ‘deep but slender’ concept was based on analysis of the wheat crop. According to research, a wheat cultivar with deep, slim roots is more suited for semi-arid climates. This could have occurred because wheat plants with deep root systems had access to water that was located farther down in the soil. Higher grain yields were possible due to the plants’ sparing use of resources in the roots due to the leanness of the root system. The concept of “deep yet lean” has gained a lot of traction, claims Bourgault. We showed that this is not a universal truth and that other crops may not exhibit the same characteristics as wheat.
The results of Bourgault’s research also demonstrate the benefits of examining crop root systems up close, particularly in semi-arid regions where water is frequently in limited supply. The next significant increases in yields for semi-arid regions, according to her, will likely result from a serious examination of root systems and an understanding of how they function. The Northern Agricultural Research Center at Montana State University served as the study’s location. The root lengths of 29 pea and 25 lentil cultivars were scanned and quantified by the researchers between 2017 and 2019. The amount of investment in root systems varies significantly across the pea and lentil varieties, according to Bourgault. In lentils and peas, Bourgault and her colleagues are currently trying to find genes or genomic areas linked to reliable data on root traits. That might modify the way root traits are introduced in breeding programs, she says.
The Montana Fertilizer Advisory Board, Montana State University, and the USA Dry Pea and Lentil Council all provided funding for this study.