New research conducted by scientists at the Donald Danforth Plant Science Center and Cornell University successfully produced fertile hybrid offspring in soybeans using a biotechnology approach. The study published in the Plant Biotechnology Journal revealed that obligate outcrossing with the Barnase/Barstar lines can amplify hybrid seed sets and enable large-scale trials for heterosis in soybeans.
Soybean is 99 percent self-pollinated, which prevents gains from hybridizing. For over a century, hybrid breeding for increased vigor has been used to boost agricultural outputs without the need for higher inputs. This approach has led to substantial gains in crop productivity, but some barriers have limited soybean improvement through hybrid vigor. Soybean flowers self-fertilize before opening and thus are not readily amenable to outcrossing. This is in part due to the limitations of current approaches, which have failed to produce reliable obligate outcrossing in soybeans.
The research team showed that the Barnase/Bastar male-sterility/male-rescue system can be used in soybeans to produce hybrid seeds. By expressing the cytotoxic ribonuclease, Barnase, under a tapetum-specific promoter in soybean anthers, they were able to completely block pollen maturation and create male-sterile plants. They also showed that fertility can be rescued in the F1 generation of these Barnase-expressing lines when they are crossed with pollen from plants that express the Barnase inhibitor, Barstar.
�??Improved soybean is a long-term goal of farmers, plant breeders, and scientists,�?� says Dr. Blake Meyers, Danforth Center principal investigator and professor of plant science at the University of Missouri. He added that improvements could have a potentially substantial effect�??and offer a benefit to beleaguered pollinators as well.

[www.danforthcenter.org]