Richardson Seeds International (RSI), a subsidiary of Nuseed, has been leading sorghum advancement since 1955. This team of experts relies on years of technical field experience and a keen sense of sight to use traditional breeding methods to advance top performing sorghum hybrids.
However, not all sorghum traits can be observed visually. As a result, the breeding teams at RSI and Nuseed South America have also teamed up with the R&D team at the Nuseed Innovation Center in West Sacramento, CA to recognize important traits faster.
The teams’ combined objective is to find and confirm specific gene markers in sorghum through a process called marker-assisted selection (MAS). MAS is when the desired trait is selected based on a genetic marker or DNA sequence and essentially takes the manual guesswork out of finding specific traits. “When choosing traits in traditional plant breeding, breeders are visually looking for plant characteristics such as height, seed color, and brown midrib. Genetic markers are key when looking for not so easily seen traits such as anthracnose resistance and sugar cane aphid resistance,” said David Drinnon, RSI GM.
MAS helps mitigate field inconsistency impact on traditional breeding. “For example, if we are trying to assess sugarcane aphid resistance and there’s no heavy bug pressure that year and visual selection is difficult, we don’t need to wait for a year with high pressure to select for the traits,” further explained Drinnon. Genetic markers identify these traits regardless of them being seen in the field, dramatically increasing breeding efficiency.
MAS starts with our breeding team taking leaf tissue samples when the plants are young and about knee-high. They use a leaf punch to put two leaf disks into a 96-well plate. These samples are randomized, and the plants are marked with orange tags for later reference. If the samples are being sent from Argentina, the leaf disks are dried first and then sent to California. If the samples are from RSI, they pack the well plate into a cooler with ice packs and overnight it to the Nuseed Innovation Center in California.
Once the samples are tested, the teams review the results and discuss advancement decisions. The advancement meeting is held early in the season to ensure enough time to crossbreed the plants containing the specific gene marker to advance. Then they can harvest the crosses the same year and get them planted in the nursery.
Our team is currently working to further advance sorghum hybrids with a selection of grain improvements and herbicide tolerance. While MAS is not new technology, it is certainly being used extensively, making a positive impact on Nuseed’s sorghum portfolio by using gene marker technology to continue to develop elite sorghum lines.