JOAN CARTAN-HANSEN, HOST: There's a science to growing fruit on a tree.

Meet a researcher at the University of Idaho who knows how to raise a peach of a peach.

[MUSIC] CARTAN-HANSEN: At the University of Idaho's Parma research station, they grow 162 gene types of stone fruit, things like peaches and apples, as well as grapes and alternative fruits.

Essie Fallahi is the station's director and professor of pomology, the science of fruit crop physiology.

ESSI FALLAHI, University of Idaho: What we are doing here, we are trying to have better fruit, higher quality, better-looking fruit, and definitely safe fruit that we can present to our growers and they can grow that for the public.

CARTAN-HANSEN: Here researchers test different varieties of stone fruit under different conditions to see what works best.

FALLAHI: We are looking for better size.

And more resistant to cold.

And also we are looking for flavor, color.

So yield alone is not enough.

We have to look at the number of other factors.

This is an example of different varieties of peaches that we have.

For example, this peach over here is a giant peach called July Sun.

And it is huge and it is an excellent quality peach.

This is pf24.

This is probably 750 grams, which is close to the world record of the largest peach.

This is a flat peach.

There are different varieties of flat peach that we are testing and this particular variety is called Jupiter.

And it is a white flesh, very tasty.

This one is Sweet Dream.

If someone is interested in a yellow-flesh peach, kind of late season, actually I would say that's for early September season.

This would be the choice, Sweet Dream.

And it does extremely well under all conditions.

CARTAN-HANSEN: So, doctor, how important is the tree to the health and the production of good fruit?

FALLAHI: It is extremely important because imagine that the leaves on the tree, they are like a laboratory.

It's manufacturing all of those goodies, all of the food that the fruit takes from them.

CARTAN-HANSEN: So for better fruit, scientists test better ways of taking care of the trees.

FALLAHI: We want to make sure the tree is pruned and trained in such a form that can harvest the sun, if you will, harvest the sun, it means it can take the energy of the sun without being blocked by the canopy.

Therefore, we need to expose them to the sun.

As an average, a fruit like this, it is probably the best quality you can imagine, needs to have 70% of light penetration inside of the tree canopy in order to produce good fruit for this year and also strong buds for next year.

Just as a general rule, if you stay in the shade of your tree in the backyard, end of June or early July, if you see sunlight is penetrating through the canopy, you see sunlight on the floor right on the drip line of the tree, you know that the pruning was done right.

But if you are standing in the shade, it is completely shade, almost dark, that is too crowded.

CARTAN-HANSEN: Okay.

Let's go look at some of the different varieties you have here.

So what are these?

FALLAHI: This is quince, this is one of the many alternative fruits that we are testing in this orchard.

Quince is native to Iran, and it is used for jelly and jam.

CARTAN-HANSEN: So what is this?

FALLAHI: This is a new plum that basically, the gene bank of that, is from Iran, and it is fantastic.

CARTAN-HANSEN: Oh, wow, what a different taste!

Yum!

FALLAHI: It is a different taste, and we are trying that here, and our growers are extremely excited about that.

CARTAN-HANSEN: The team shows off this year's crop at the station's annual fruit day celebration.

It's a chance for growers to see and taste new varieties and to find out the latest science has to offer.

FALLAHI: Science is very important in fruit production and growing trees.

Why?

We need through science to know what makes a tree more efficient in terms of production.

For example, if a large trees you may need 40 leaves for one fruit.

But in a more efficient tree, a more dwarf trees, you may only need 20 leaves per fruit.

CARTAN-HANSEN: And the best part of growing a more efficient tree is that you get to eat your research.

FALLAHI: This is a wonderful-tasting peach.

CARTAN-HANSEN: If you want to learn more about trees, check out the Science Trek website.

You'll find it at science trek dot org.

(MUSIC) Major funding for Science Trek is made possible by the Laura Moore Cunningham Foundation, helping Idahoans reach new heights for generations.

Additional funding provided by the Idaho National Laboratory, mentoring talent and finding solutions for energy and security challenges, and by contributions to the Friends of Idaho Public Television from viewers like you, thank you.