What are different "strains" of the same apple cultivar?

Many cultivars of apples have multiple strains or selections which will have different names usually in front of the cultivar i.e. Grand Gala, Gale Gala, Fulford Gala, etc.  These different strains are all of the same cultivar with some unique characteristic usually relating to color, size, or maturity.   The availability of different strains is more prevalent in some cultivars than others.…

What does "low ethylene" apple cultivar mean?

Ethylene is a small gaseous molecule which is present in all plant tissues.  Interestingly, it is a plant hormone and is actively involved in many physiological processes.  One very important process in apples in which ethylene is intimately involved is ripening.  Specifically, ethylene is the triggering molecule for apple ripening.  If ethylene is removed from the fruit or its production is limited within the fruit, ripening will be slowed or, in some cases, nearly stopped.  Low-ethylene cultivars have an inherently …

Do scab-resistant apple cultivars still need to be protected against scab infection?

Yes. Fungicide applications are an essential component of effective scab management, even though a cultivar may be resistant to the scab fungus. The fungicide applications contribute to the preservation of the plant’s resistance genes, which are subject to continuous evolutionary pressure from plant pathogens. For scab-resistant cultivars in particular, the most critical period for fungicide applications is during the primary infection cycle in the spring. Spores from over-wintered leaves on the ground are the “offspring” of the previous year’s infections …

How do I find out if two apple cultivars are effective to cross pollinate?

Nursery catalogs or their web sites often list apple pollination charts or recommend good apple varieties to use as pollinzers. Varieties listed in these charts have overlapping bloom periods and are effective pollinizers. However, some varieties, such as Winesap, Stayman, Mutsu, and Jonagold, produce sterile pollen and therefore cannot be used to pollinate other apple varieties. …

How do I select the best "strain" of an apple cultivar?

In selecting the best strain of a cultivar it is important to talk to other fruit growers, cooperative extension personnel and nursery owners. Solicit advice from these groups that know your local growing conditions. Check to see if any of these people have trees of the strain you are interested in and visit their orchards to see fruit on the trees. If you are looking to plant large acreage of a particular strain you should set out a few trees, …

Is there a chance that a scab-resistant apple cultivar will become scab-susceptible?

Yes, and several scab-resistant cultivars already are scab-susceptible at some locations. Most scab-resistant apples trace their origins to a collaboration between Purdue University, Rutgers University, and the University of Illinois. The PRI apple breeding program began in 1926 when crosses made from the crab apple, Malus floribunda 821, were found to show some resistance to apple scab. The PRI group then bred the resistant Vf gene from Malus floribunda 821 into commercial apple cultivars. Decades of subsequent hybridization and selection …

Does an apple cultivar ripen at the same time every year?

Not necessarily. Time of apple ripening is affected most by bloom date and growing season weather. For example, McIntosh typically ripens 125 Days After Full Bloom (DAFB), but can range from 115 to 135 DAFB. There are formula(s) for determining harvest timing, for example, this one for McIntosh from Cornell University. In any year the best indicator of maturity and harvest timing is a combination of flavor and fruit background and over-color, but the starch-iodine index test is also …

What are fruiting spurs on apple trees and why do some cultivars have more than others?

The term fruiting spurs does not have a universally agreed upon definition. Most fruit scientists consider fruiting spurs to be short shoots, usually less than 6 inches long, with a rosette of leaves just behind a fairly large bud at the tip of the shoot. the large bud (the terminal bud) is usually a flower bud, from which a cluster of five flowers will emerge the following spring. Spurs arise from portions of a branch that are at least two …