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Wisconsin Fast Plants Program Research Notes

The Wisconsin Fast Plants research team is continually improving and developing new lines of Fast Plants and other Rapid-cycling Brassicas. One of our current breeding projects aims to re-stabilize the genetics of the Rosette-Dwarf Fast Plants stock. This project began after observation of a low frequency off-type trait, a green stem, that is undesirable for this stock. The goal is to breed out any plants with the undesirable green stem trait, thus ensuring that the Rosette-Dwarf stock is true breeding for high purple anthocyanin pigment expression.

To accomplish this project, we need to produce a Rosette-Dwarf population without any green stems. This poses a challenge, because the green stem trait is controlled by a recessive gene. Therefore, a plant may appear purple (the dominant trait) while still being heterozygous for the undesirable green stem, making visual identification of off-types difficult. A unique approach was needed to identify and remove off-types from the population.

Stem color phenotypes, for given dominant/recessive genotypes

Plants that are heterozygous for a recessive trait can be indirectly identified: by individually self-pollinating* each plant in a large population of parent plants and then examining the phenotypes of the offspring. This practice applies Mendelian principles of inheritance in observing selfed-offspring phenotypes to determine the genotype of a parent plant. However, as discussed in a previous entry on pollination, Fast Plants typically require cross pollination to produce seed.**

*Self-pollination occurs when pollen from one individual plant is transferred to a flower on the same individual plant (i.e. the plant is fertilized with its own pollen). This contrasts with cross-pollination in which pollen from one plant is transferred to a flower on a second plant.

**Fast Plants require special techniques at the appropriate time in a plant’s development to accomplish self-pollination.

To learn more about this ongoing project, await our upcoming blog (current blogs can be viewed here) and follow us on social media to stay in the loop!