There are several possibilities why apple trees bloom but fail to set fruit:
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | Ottawa 3 |
Introduced by the Agriculture Canada Research Station in Ottawa, Ontario, Canada in 1974 as a hardy dwarfing rootstock. The parents were M.9 and ‘Robin’ crab. Ottawa 3 roots poorly in the stoolbed and is often micropropagated. Trees are precocious and produce few rootsuckers and burrknots. It is sensitive to apple stem grooving virus. Ottawa 3 was included in the 1990 NC-140 cultivar/rootstock trial at 12 locations and the 1990 dwarf rootstock trial at 8 |
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. …
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | P.2 |
Resulted from a cross of M.9 x Common Antonovka and released by the Research Institute of Poland in Skierniewice, Poland. This is a productive, cold hardy, dwarfing rootstock slightly more dwarfing than M.9 NAKBT-337. It is susceptible to fire blight, and wooly apple aphid, but fairly resistant to crown and root rots. It produces few root suckers and burr knots similar to M.9. In NC-140 trials trees survive; depaending on location tree size was similar |
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, …
The simplest approach to measuring productivity is to assess yield on a per-tree basis; it is straightforward and easy to understand. The problem comes when comparing trees of different sizes. For instance, comparing the productivity of apple trees on M.9 NAKBT337 and those on G.30 on a per-tree basis would be meaningless. The size of trees on M.9 NAKBT337 would allow much greater planting densities than would that of trees on G.30. Therefore, trees on M.9 NAKBT337 could have a …
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 …
Pomological researchers have assessed other approaches to determining potential yield. Since planting density works together with per-tree yield to determine productivity per acre, researchers have used canopy dimensions to estimate planting density and then estimated potential yield per acre. This approach is perfect if the trees used to measure yield and canopy size are not contained by any pruning. Once the canopy is manipulated, and particularly if it is manipulated differently for trees of different sizes, potential yield per acre …
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 …
Harvesting apples with their stems intact will prevent fruit loss. Detached stems provide a point of entry for microorganisms and can result in decayed fruit. …
