Doubled haploid techniques help improve sorghum breeding timeframes

Something that could take up to a half dozen years to complete can now be developed in a couple of years. In the plant-breeding world, it’s nothing short of a small miracle.

Research by Tanveer Hussain, Cleve Franks, Amira Kajtazovic and Paul Huettl, Corteva Agriscience, Johnston, Iowa, showed doubled haploid is the shortest route to obtain instant homozygous lines. The introduction of the DH approach into breeding programs can reduce the times and population sizes required for production of pure lines in comparison with conventional selfing or back crossing.

“This is a breeder’s tool that will advance the sorghum technology pipeline and enable farmers to see new technologies in their field faster,” said Franks, who is the Corteva Agriscience sorghum research scientist and Coastal Plains evaluation zone lead.

For sorghum, a doubled haploid breeding system allows parent lines to be developed in two years, where it currently takes up to seven years to complete, according to USCP.

The doubled haploid technology is already being used in other crops like corn and canola. For companies like Corteva, DH techniques help improve plant breeding efficiency and effectiveness by generating inbred lines with 100% purity in one or two generations, depending on the crop. Genetic gain per cycle is increased and as a bonus, costs are reduced when it comes to research and development.

To produce DH lines in a mass to meet needs of breeding programs, researchers found that a simple, reliable and efficient genotype-independent doubled haploid system is what they needed. This allows breeders to evaluate the subsequent germplasm in homozygous backgrounds faster.

In their research, they’ve discovered two sorghum haploid inducer lines, SMHI01 and SHMI02.

As for sorghum, this breeding system greatly increases the scale of which a sorghum breeding program can generate parent lines, thus drastically increasing the number of hybrids tested each year, Justin Weinheimer, Sorghum Checkoff crop improvement director said.

“The end result of this will be increased chances to improve sorghum yield or bring other valuable traits to the farmer,” he said.

It also serves as a force multiplier, in that it greatly enhances the power and efficiency of other technologies, such as molecular markers. Eventually, once the sorghum makes it to farmers’ fields, it gives them more options.

“While farmers will not use or see the doubled haploid breeding system in their field, they will see the results of this breeding tool in the hybrids they plant,” Weinheimer said. “Seed developers using this tool to make hybrids can offer more hybrids with greater agronomic performance than previous generations leading to greater farm profits.”

It’s simply a breeder’s tool that will help advance sorghum technology, and Weinheimer sees the benefits to this kind of work.

The United Sorghum Checkoff Program teamed up with sorghum breeding leadership at what was then Pioneer, now Corteva, starting in 2014. They agreed there was a change needed to allow sorghum genetics to compete long term.

“The Sorghum Checkoff invested with Corteva to develop the doubled haploid breeding system now in its second phase of partnership,” Franks said. “The collective project using Corteva’s world class sorghum breeding program set a goal to make a revolutionary change in sorghum by developing this tool.

Partnerships with seed companies also afford a direct route to deliver the benefits of this technology to growers’ fields in the fastest possible way. The project currently runs through 2020.

“While major strides were made in 2017, by discovering a key element of this tool, the remaining project years have been spent further developing the system,” he said. “This tool has several steps and each step needs to be refined such that it is not only efficient but economical for a breeding program to use.”

According to USCP, the goal is to develop a holistic, end-to-end system that sorghum breeders can use at scale to produce the volume of doubled haploids they need to effectively drive genetic gain.

In a 2017 news release from USCP, the program funded the then DuPont Pioneer research as part of a three-year, $800,220 investment. The research, conducted in Texas, Kansas, Puerto Rico, Mexico and Iowa, leveraged the world-class, global breeding programs of DuPont Pioneer.

“The inducer lines discovered by DuPont Pioneer will give sorghum breeders the opportunity to create finished inbred parents in a single step,” Franks said in a news release. “This could accelerate the breeding process by potentially cutting the time required to create new hybrids in half.”

The results and developments from the partnership will be available for out licensing. As one of the top five cereal crops in the world, sorghum can be grown as a grain, forage or sweet crop. The United States is the world’s largest producer of grain sorghum, having produced 597 million bushels in 2015. The United Sorghum Checkoff Program partners with both public and private sorghum breeding entities.

Sorghum groups are committed to making this technology available and affordable to everyone involved in sorghum improvement, both public and private.

“It promises to be a truly transformative tool that will greatly enhance the ability of sorghum researchers to utilize other emerging technologies, such as genomic predictions and CRISPR,” Weinheimer said.

Kylene Scott can be reached at 620-227-1804 or [email protected].