I think the way it works is that they will cross two varieties with promising characteristics and plant something like 1000 of the resulting seeds and then monitor the results and pick the handful that have some promise to evaluate further and abandon the rest.

I think in some cases the seedling can be grafted to an established tree to yield fruit sooner for evaluation.

I'm not sure if I'm answering what you're asking, but I'll give it a shot.

Most new apple cultivars are a result of controlled crossing have been bred in university or private breeding programs (older ones are often chance seedlings). Crosses are made by choosing two parents (which are not always cultivars...they could be selections in the breeding program which have good characteristics, but aren't good enough overall to be released as cultivars)that have characteristics the breeder is hoping to combine. For instance, there may be an apple that's scab resistant, but has crappy fruit, so he'll cross it with a cultivar that has excellent fruit. That's kind of a simplistic example, but it works. :)

Anyway, flowers on the female parent are emasculated (male parts ripped off) before the flowers open to ensure the flower has not already been pollinated. Then, pollen is collected from the male parent and is placed on the stigma of the female parent. The flower (or what is left of it, anyway!), is quite often covered in cheesecloth for 24-ish or more hours to ensure no other pollination occurs.

Then, the breeder crosses his fingers and hopes that the cross takes! The fruit is allowed to develop normally and the seeds are harvested.

The number of crosses made between two parent depends on two things:
1. The number of seedlings of that cross the breeder wants to evaluate (germination % comes in to play here)
2. The number of seeds the breeder can expect to get from a cross (it's much easier to be a strawberry breeder than a cherry breeder because of this!).

The seedlings are then planted (and in the case of tree fruits, often grafted onto rootstocks) and evaluated. Initial selections are made, and from there, go into more advanced trials so that they can be better analyzed.

Strawberries are considered a "quick" fruit to breed, and it usually takes at least 10 years after the cross is made to when the cultivar is released.

However, the use of modern genetics tools (such as marker assisted selection) can help speed up and streamline the breeding process.

Fruitgirl, thats what I was after, an explanation of the actual crossing process. Very interesting. Thanks all

Here is a old movie on apple breeding

Here is a link that might be useful: Apple breeding

The majority of famous heirloom apples are chance seedlings. The notion that you will get crab apples from apple seeds is pure nonsense, yet another urban legend. Crab apples are a different species of malus and will cross breed with regular apples hence some seedlings from such crosses will revert to crab apples.

In modern breeding programs where special characteristics are sought such as disease resistence, many seedlings are tried and very few selections are made. But for backyard fruit, seedlings will often produce decent fruit, but only it they are manually pollinated. Many commercial orchards use crab apples for cross pollination hence the notion of getting crab apples from seeds of store bought fruit,