Pre-harvest Drop

Apples sometimes drop to the ground before they reach the desired harvest maturity. This pre-harvest fruit drop can cause significant losses in apple orchards. As apples mature, an abscission layer of specialized cells naturally forms between the apple stem and the fruit spur to which it is attached. The abscission layer allows the apple to be released from the tree without causing damage to the tree. However, apples may fall off the tree before the ideal harvest maturity has been …

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.…

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 …

How do I know when it is the right time to pick an apple cultivar?

Time of harvest depends on the intended use of the apples.  Apples that will be consumed immediately can be left on the tree longer than those intended for cold storage. Generally, fruit can be harvested from the tree over a couple of weeks. Fruit that drops from the tree is usually over ripe.  To determine the approximate time of harvest, check a fruit tree nursery catalog or their web site for a list of harvest dates for various cultivars. These …