Rewiring Plants For Reproduction To Increase Seed Production
In farming communities in sub-Saharan Africa (SA), the quirks of plant breeding can be exploited to improve yield per hectare of sorghum and cow beans, two of the main crops.
That was the end of Hy-Gain, a multimillion-dollar international collaborative research project led by Anna Koltunow, a professor at the University of Queensland, and supported by the Bill and Melinda Gates Foundation.
Professor Anna Koltunow said: "Hy-Gain is designed to enable small farmers to preserve and sow high-yield hybrid sorghum and Cow bean seeds."
Hybrids (inbred, the offspring of genetically different parents) were unusually strong and the yield per unit area increased significantly.
But these properties are not retained in any seed produced by hybrid plants because they are formed by sexual seed formation. It requires a pathway of meiosis and fertilization.
Professor Corturno says sexual reproduction naturally separates the genetic traits in the seeds formed in the hybrid flowers.
"The key to keeping hybrid seed yields up from one generation to the next lies in one of the strangest aspects of plant reproductive biology: 'apomixis', the naturally occurring asexual seed formation pathway in plants," she says.
"If a high-quality hybrid seed is equipped with a genetic switch that allows it to asexually reproduce a plant with a new seed, i.e., without meiosis and fertilization, the resulting seed will produce a plant that is identical to the clone of the hybrid parent.
"This will allow hybrid seeds to be retained and re-planted on farms for generations, enabling farmers to increase production and save on the cost of purchasing hybrid seeds each year."
Hy-gain consists of six research organizations and a multinational seed company. It was previously a five-year project led by Professor Koltunow and partly funded by the Bill and Melinda Gates Foundation.
One of the most obvious aspects found in previous studies, says Prof Corturno, is that the change required to switch from sexual to asexual is relatively small.
"With Hy-Gain, we are developing plant prototypes to test whether we can target these valuable hybrid traits when hybrids are sown, bloom and produce more varieties," she said.
"The goal is to provide regionally-specific sorghum and cow bean varieties adapted to African needs with higher yields and resilience.
"The goal of the Hy-Gain team is to deliver forward a very useful technology that can be easily and cheaply used for breeding.
"Domestic breeders of cow beans and sorghum need to be able to connect with their farming communities and make decisions about the varieties in their area."
If successful, Professor Koltunow says, Hy-Gain technology could be a potential "game-changer" for farmers around the world, including those in Australia's sorghum breeding program.
Professor Koltunow said: "This technology could make plant breeding and seed production more efficient at a time when the grain industry is dealing with the challenge of maintaining yield per unit area in growing conditions that are getting hotter and drier."