September 17, 2016

1 - Pear trees (and many other fruit trees) can be cross-pollinated by other varieties of the same species, in fact, some require another variety for pollination.

Yard and Garden September 17, 2016

Q.

I have two pear trees that I am trying to figure out their variety. I have looked online extensively but cannot find much detailed description or a methodical way to figure it out.

The trees are at least 30 years old, if not older, so they are probably not be a "newer" variety. The pears are not changing color after being picked. I think they look like a 'Comice' pear, which is also called a Christmas Pear or French Pear. They are greenish with a red blush and are short and squatty.

Also, I have a pollination question. Can two different pear trees cross-pollinate and produce a "hybrid pear" that has a blend of the two types? For that matter, can apple trees do that as well?

A.

This is a challenging question! Identifying the specific variety of many fruits can be difficult. Shape, color development, flavor, and crispness are characteristics that may help. There is some information that may be helpful at USA Pears. However, the description of the fruit does sound like 'Comice' pear. The website I listed above provides descriptive material about flavor and texture that may help separate it from the 'Seckel' or other variety that looks similar. Size may also be a characteristic that distinguishes varieties, but that is culturally and environmentally dependent.

The other question regarding pollination is somewhat easier to answer. Pears will cross-pollinate with other pears, in fact many varieties need proper pollinator varieties to maximize fruit set and yield. Some pears are "self-fruitful", meaning, that they can be pollinated by flowers of the same variety. Other pears need a different variety blooming at the same time to provide pollen because they cannot be pollinated with pollen from their own variety. Most pears will produce more fruit if they are cross-pollinated, even if they are self-fruitful.

Whether the fruit are the result of cross-pollination, or self-pollination, seedling trees grown from these seeds will exhibit characteristics that differ from the parents since they are genetically heterozygous. That means the variety began as a seedling that had maternal and paternal parents whose genetics combined to produce the current variety. The parents themselves were produced by cross-pollination and also had genetic input from different parents. Seedlings grown from these seeds will exhibit the genetic characteristics that are the result of the specific set of genes it inherited. They will be different from their parents and other pear varieties. It is unique. The variety you are growing had been selected from other seedlings because it had superior characteristics from other plants. Our contemporary plant varieties may also have developed from buds on a branch that mutated, altering their genetic characteristics, so that fruit on that branch was different from fruit on other branches of the same tree. It was then clonally propagated (usually by grafting) for years or even hundreds of years to clonally preserve the characteristics desired. The genetic makeup of the plant determines whether or not cross-pollination is absolutely necessary. This information is true for both apples and pears (and most other fruits).

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

Links:

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