Scientists are unearthing new knowledge about lentils in research that aims to discover root traits that will help breeders develop drought-tolerant varieties to increase production of the pulse.
The research is the first of its kind in Australian lentil varieties, as root research, particularly in pulses, is still in its infancy.
Agriculture Victoria Research Scientist Dr Shiwangni Rao said knowledge of the whole plant is integral to understanding plant growth.
"I think of it as going to war with a spear, but no shield. If you are trying to increase pulse production and you are only looking at above the ground and not below, you are only addressing half the question," Dr Rao said.
Most of Australia's lentils are produced in Victoria and South Australia, and export opportunities were boosted recently after India cut tariffs on Australian lentils from 30 to 10 per cent.
This research involved planting 36 lentil varieties in PVC tubes in the glasshouse at the Agriculture Victoria Research Horsham SmartFarm.
At maturity, the roots were washed, scanned and measured for a range of traits such as root length, surface area and average diameter. The second part of the experiment involved planting a range of lentil and field pea varieties under rain-fed conditions in the field, and a hydraulic corer was used to collect root samples for analysis.
"Using the corer – a machine that digs out cylinder-shaped samples – we collected 2,600 cores from 408 plots over the growing season."
"Rhizotron is like a colonoscopy for soil, and we can use it to visualise the plant roots. We stick a clear tube in the soil at the start of the season, and as the plant grows around the tube, we can pop a scanner inside and obtain images of the roots at any time," she said.
This research is ongoing; however, the team have so far identified five different root architecture forms associated with different varieties.
"The range of root shapes is greater than we expected, and they differ considerably in terms of distribution, depth and diameter," Dr Rao said.
One interesting correlation the research team aims to reveal is the use of above-ground traits such as canopy temperature to predict root traits.
"It is hypothesised that varieties with cooler canopies have deeper roots, but last year the weather was too wet – we hope there will be some interesting correlations this year."
Understanding the root architecture of lentils will benefit breeders and grain growers.
"This information will help breeders when they are looking to cross different varieties for local adaptation to different growing regions," Dr Rao said.
"They may cross a good yielding variety with deep roots for the low rainfall zone or a shallow root system with a lot of biomass for the high rainfall zone, additionally if they need to address boron toxicity or salinity there are roots that are resistant to those constraints."
Dr Rao said this knowledge will also help growers improve production and adapt to the changing climate.
"Drought has a major impact, and it is hard to predict when it will strike so we definitely need all the tools in our toolbox to address unpredictable rainfall, and even when it is not a drought year, an efficient root system means better yield."
This research is part of the Victorian Grains Innovation Partnership between the Grains Research and Development Corporation and Agriculture Victoria, and is aligned with the Grow, Modernise and Protect themes of the Strategy for Agriculture in Victoria.
