Most modern fruit breeding involves having grad students carefully bag flower buds with gauze bags, then removing the bags at the proper time, surgically remove the petals and anthers, brushing on pollen from selected male specimens, rebagging, coring out fruit, growing seedlings in a greenhouse and then selecting.
There is another model. It is called Mass Selection.
The advent of DNA testing revealed that many of the controlled crosses....were not. Somehow, mother nature and/or an enterprising pollinator circumvented the best laid plans of the major professor.
The idea behind mass selection is that since controlled pollination is partially fiction, why not plant prodigious quantities of seeds that are likely to have the desired parents?. In the case of my pear experiment, the maternal parent is Potomac and the likely pollen parent is Olympic. These trees are planted close together. In fact, the branches interlace (it is like when I am walking so close to my wife that I can put my hand in her pocket). They bloom at the same time. Many of the fruit on each tree were likely to be pollinated by the other tree.
My goal is to select pears that are precocious (produce fruit early in life), resist most common pear diseases, ripen late, taste great and keep in common cold storage until February.
Efficient sorting:Efficient sorting is considered an obsolete subject. Everybody has huge amounts of computing power and massive amounts of storage capability.
But I used to work with very large databases using an antiquated Time Sharing computer and my project were assigned back-burner priority. I learned a few lessons about efficient sorts.
The first lesson is to thin the herd as quickly as possible. I might have four criteria to sort on. One criterion might weed out 5%, another criterion might remove another 10%, the third criterion might remove 20% and the last criterion might remove 99%. Sorting through five million records required 17.4 million actions if sorted in the order listed. Reversing the order reduced the number of actions to 5.2 million actions or about one third of the inefficient way.
One might think that a plant breeder would be extremely protective of his creations. Well, we cannot afford to be; at least in the early stages. The watch words are to kill them quick and kill them cheap.
I placed an email to Joseph Postman, one of the curators at the Pear Germplasm reserve in Corvallis, Oregon. I asked him if there was a quick, easy way to sort through the seedlings to determine if, in fact, they were the assumed cross: Potomac X Olympic?
He responded in less than an hour.
He said to look at the edges of the leaves and I would see that the Olympic was saw-toothed and the Potomac was smooth. Seedlings of the two will show the saw-toothing but Potomac by other pollen parents will likely not.
|Olympic leaf on left, Potomac on right|