Selecting the Next Generation
By Olivia Steinmetz | April 25, 2022
As winter slowly fades into spring, the first major task we do as field season begins is dig up plants from our established nurseries. Digging up plants is a time where we are making selections and deciding what to move forward in our breeding program: we are choosing certain plants over other plants. The plants that we choose are going to be the biggest, the best, and the healthiest. These top performing plants will become the “parents” to a new generation. This is how we begin a new potential variety!
Every spring we transplant thousands of alfalfa plants out of the greenhouses and into field nurseries (see “Winter in the Greenhouse” for more details.) We maintain these nurseries for multiple years, adding on to them year after year as we work with multiple populations and multiple traits of interest. The longer that the plants are in the nurseries the better – this leads to more differentiation from plant to plant as the weaker ones die off and the stronger ones shine through. That way when it comes time to select parent plants out of the established nurseries, we know their pedigree, what other selections they have gone through (such as a disease screen), we know they have great persistence as they’ve survived multiple winters, and we can select for yield as we choose the biggest plants. Out of the hundreds of plants within a population’s nursery, only 50-100 are chosen to move forward to the next stage.
The parent plants that we dig up and select are shipped out to Idaho, where all our seed production takes place. These plants are put under a “cage,” which is a PVC-pipe and mesh contraption that protects these plants from other pollen contamination. We want to make sure that at this stage of variety development, the population is pure. Leafcutter bees are put into the protected cage once these parent plants are flowering to pollinate all the plants and generate seed for that next generation.