AMES, Iowa Agronomists at Iowa State University are offering doubled haploid technology that allows corn breeders to more quickly produce inbred lines for research or private use.
Thomas Lbberstedt, associate professor and K.J. Frey chair in agronomy and director of the R.F. Baker Center for Plant Breeding, has launched a Doubled Haploid Facility at ISU that can develop pure, inbred corn lines in less time than traditional methods.
Inbred corn lines have two copies of the same genome. They are sometimes called pure lines, because after self-pollination (same plant is both male and female) all offspring are identical to the parent plant. They are an exact replica of the single parent and are valuable for research or commercial use.
These homozygous plants have two identical copies per gene, while heterozygous plants, such as hybrids, frequently have two different copies per gene.
Offspring of hybrids are genetically segregating because they received their two genomes from different male and female plants. This is the reason why hybrid seed has to be reproduced from stably maintained inbred plants. Corn crop produced from seed that has not been harvested from hybrids will not only segregate but also show reduced hybrid vigor.
"If you want to develop new inbred lines, you would start out with a plant that is heterozygous. Then by self-pollination you can increase the homozygosity each generation. But you need maybe five to eight generations before you have an inbred line that is pure enough so that you can combine two inbred lines to create such a hybrid," Lbberstedt said.
The Doubled Haploid Facility at ISU will allow development of pure, inbred lines in only two generations, taking about one year.
"With the doubled haploid process, you start from the same place, but by a biological trick, the offspring do not contain two genomes as usual, but only one. Then you have a chemical treatment, and after
|Contact: Thomas Lbberstedt|
Iowa State University