FFAR Research Revolutionizes Hybrid Seed Production

Hybrid crop plants produce higher yields than their non-hybrid cousins, but they are expensive to create. To make hybrid maize seeds, for example, farmers must plant alternating rows of male and female plants, with each containing a different desirous trait, and then harvest the resulting hybrid seeds. This process requires 33 percent extra land as well as the use of specialized tractors, which compact the soil and burn fossil fuels. Rice and wheat hybridization, too, rely on cumbersome systems which are highly sensitive to adverse environmental conditions while many crops, including most legumes and sorghum, are not available to farmers as hybrids due to the difficulty of cross-pollinating them.

Further increasing costs, high-yielding hybrid strains cannot currently be maintained from season to season. Existing hybrid plants generate a second generation of seeds, but the seeds are not as productive as the first generation because optimal gene combinations are not retained. Thus, the hybridization process must be repeated every season.

UC Davis researchers are optimizing newly discovered synthetic apomixis technology to reduce the cost of developing and maintaining hybrid strains. Apomixis is a process in many plants that reproduce asexually, avoiding the genetic variability in the next generation that arises from sexual reproduction. Synthetic apomixis is the application to crop plants that allows hybrids to produce seeds that are clones of the parent plant, with the same high yields. Using genome editing, the research team is introducing apomixis to rice plants and aims to boost the frequency of clone seeds in affected plants from 30 percent to 90 percent. The team also plans to introduce the improved synthetic apomixis technology in maize, which shares many key features with rice and has a large demand for hybrid seeds. Rice and maize provide the majority of calories in the developing world. Incorporating synthetic apomixis into cereal crops, therefore, would go a long way toward sustaining global food security.