What is cubing?
An alternative F1 hybrid breeding method I’ve used borrows from the “cubing a clone” technique. This is the technique of mixing pollen from all the selected males. This method guarantees that from the very first group of seedlings, a predefined fraction will be the offspring of the best male plant (defined as the male responsible for creating the best daughters). They will be easy to identify, being the superior plants.
The disadvantage of this method is that the identity of the responsible male is lost, rendering that specific cross difficult to repeat. That’s a major disadvantage if the intention were commercial production of the hybrid strain. However because it’s more time-saving & practical, mixing the pollen is the best method for home breeders wishing only to obtain a great clone mother. One need only germinate a large enough group of seeds to ensure several female offspring of each select male & the future clone mother will be among them.
Cubing a clone is a way to create a unique seedline (a “strain”) modeled after a currently existing female individual. The goal is to create seeds from which the females replicate the phenotype of the original female. Obviously the chosen female should be an outstanding specimen.
CONTINUOUSLY KEEP A MOTHER IN THE VEGETATIVE STATE TO PROVIDE CLONES
1. Pollinate a flowering clone of the original female with the pollen of a related male, preferably her father or a brother. The resulting seeds contain 1/2 the original female's genes and 1/2 those of the male. An unrelated male won’t have the Y-chromosome of the chosen female’s family & therefore any Y-linked traits of the family will always be missing in the seedline.
2. Grow the above seeds & flower them. Collect an equal quantity of pollen from each selected male and mix it together.
3. Pollinate a flowering clone of the original female with the above pollen. These seeds contain 1/2 the original female’s genes plus 1/4 more because the male used was 1/2 her genetics too. I call this generation “.75” to capture the idea that it’s 3/4 of the original female’s genetics.
4. Grow the above seeds & flower them. Collect an equal quantity of pollen from each selected male and mix it together.
5. Pollinate a flowering clone of the original female with the above pollen. These seeds contain 7/8 the original genes (1/2+3/8), the ".88" generation.
6. Grow the above seeds & flower them. Collect an equal quantity of pollen from each selected male and mix it together.
7. Pollinate a flowering clone of the original female with the above pollen. These seeds contain 15/16 the original genes (1/2+7/16), the ".94" generation. Theoretically this will be a stable, true-breeding seedline from which all females are replicas of the original.
Note that in cubing we have no further use for the males of previous generations after taking their pollen. Therefore mixing the pollen & losing the identity of “best male” is no problem here. The goal of the cubed strain is to reproduce the female phenotype, independent upon P1 generations for reproduction after a certain number of steps in the cubing process.
I recommend carefully evaluating the females produced in each generation of the cubing process to monitor their progress. If the results don’t progressively shift toward your goals, then you may have to change your male selection parameters.