Friday, September 20, 2013

Eaton Rapids Joe Pear Breeding Project

I decided to try my hand at pear breeding.

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
I love competent, helpful people.


  1. In his later years, my Dad had a pear tree in his orchard that wasn't producing properly. He considered the options and settled on grafting. He did his research and started grafting stock onto that tree. The year he died, that tree produced nice different varieties of pears, all from the same root stock.

    When I lived on the farm, I had a grafted pecan tree. One side produced Stewarts, the other side produced Paper Shells. Both sides were grafted on common native root stock.

    Sometimes grafting is the best solution to getting the fruit you want.

  2. I like messing around. By my reckoning I have about 30 good years and I have 10 acres to mess with.

    I do know how to graft and will likely graft the most promising seedlings into the tops of older trees to get an advanced preview.

    Even if all the seedlings prove to be duds, they will provide many rootstock for me to graft over.

    I have not kept count but suspect that I have fruited out over 20 varieties of pears looking for what I want. Shenandoah looks close.

  3. Has anyone had success growing pears or apples without any spraying at all?