Posted on October, 29, 2024 at 10:23 am
A research team led by The University of Queensland is making strides toward addressing a significant challenge for Australian farmers through targeted breeding aimed at improving yields in sorghum crops.
This effort is part of a five-year, $12 million collaborative research investment involving industry and government, focused on reducing sorghum lodging.
Professor Andrew Borrell, from the Queensland Alliance for Agriculture and Food Innovation, said sorghum lodging occurs when the plant lacks sufficient water, costing growers an average of $12 million annually in yield.
“Lodging is where the stem breaks just before harvest, usually as a result of drought that occurs during grain filling,” he said
“The sorghum panicle requires a certain amount of carbon and nitrogen to fill the grains, which is normally provided through photosynthesis.
“But if you have a drought after flowering and the leaves begin to die, the plant takes carbon from the stem to fill the grain, hollowing out the stem and making it more prone to breaking.
“What’s even worse is that lodging often happens late in the grain filling period – you have farmers looking at a great crop in the field but then the stems fold just before harvest.”
Project lead, Professor David Jordan, said advances in genetics and lodging still remains a complex issue.
“What plant breeders need is a reliable method to screen plants for lodging resistance,” he said.
“However, high-yielding plants with their heavier grain loads tend to be more susceptible to lodging, creating a dilemma. If we select for lodging resistance, we often end up with lower yields, but if we focus on high yields, we see more lodging.
“While the direct impact of lodging is significant, its biggest impact comes from farmers growing lower-yielding varieties to avoid the risk of lodging.
“Our goal in this project is to develop a method to help plant breeders to separate and identify plant traits that resist lodging without reducing yield.”
To tackle this challenge, Post Doctoral Research Fellow Dr. Geetika Geetika highlighted that the team is examining variations in stem composition and structure in sorghum.
“Knowing which genotypes have higher stem strength will allow us to select for these genotypes and eventually breed for a stronger stem,” said Dr. Geetika.
“This will result in a genotype with a high-yielding trait and stronger or increased stem strength.
“We create artificial drought stress to promote lodging by fully defoliating the plants, among other treatments.
“Differences in stem strength at anthesis and maturity are assessed using a stem breaker that we have custom-designed to assure consistent performance and data collection.
“We know there is a wide variation in stem strength among genotypes, with contributing factors including structural features such as rind thickness and overall stem shape and diameter, as well as compositional characteristics like differences in cellulose, hemicellulose, or lignin content.”
Source: Food and Beverage