Origin: Zaiger's Genetics by Floyd Zaiger

Unique features

Independence is a distinct, self-fertile, interspecific almond tree variety that produces soft-shelled nuts with very high yields.

Its novelty consist of the following combination of desirable features:

  • The trees are self-fertile and produce their own almonds, without the need for pollinators (needs fewer bees).
  • The tree has vigor and grows upright at a quick and healthy rate.
  • Produces soft-shelled nuts that are well sealed.
  • Nuts taste good (similar to Nonpariel. slightly sweet) and are of high quality
  • Low percentage of doubles (typically less than 10%)
  • According to the patent: Harvesting period is 7-10 days earlier than ’Nonpariel’ Almond
  • According to Dave Wilson Nursery: harvesting period can even be 2-3 days earlier than Nonpariel)
  • Harvest can be done in one and single pass.
  • Blooming in the same season with ‘Nonpariel’. Independence and ‘Nonpariel’ pollens are compatible, able to pollinate each other.
  • The tree can be planted in full sun and free-draining clay, loam, and sandy soils. [3]
  • Maturity Date: August 28 to September 13
  • Chilling Hours: 400h - below 45 °F (7 °C)

These unique features of this variety are first demonstrated with Independence being budded on ‘Nemaguard’ Rootstock that are grown on (Handford) sandly loam soil with Storie Index rating of 95 and in USDA Hardiness Zone 9. Independence was first grown by Floyd Zaiger near Modesto, California. In the process, standard almond growing approaches were employed such as pruning, spraying, irrigation and fertilization.

Origin of the variety

This variety has its roots in an experimental orchard in Modesto, CA. It is a cross between a variety called 'All-in-One' (U.S. Plant Patent No. 4304) and the proprietary almond seedling defined as 21G8. Independence variety was introduced in 2010. All-in-One is interspecific as it is a cross: (Almond x Peach). Independence is thus interspecific as a cross of (Almond x Peach) x Almond).

Almond breeding programs were being executed throughout the years, in both California and rest of the world, to produce a self-compatible variety that would, in turn, transmit this self-compatibility to its offspring.

Californian breeding programs have mostly introduced self-compatibility from peach. All-in-One variety itself originates from almond x peach F2 progeny.

Flower of the almond variety All-in-One (Image source: Fast Growing Trees)

All-In-One produces heavy crops of soft-shell nuts with sweet, flavourful kernels. This variety can be grown in Northern areas as it needs less winter chilling than other selections. However, in order to ripen, All-in-One needs a hot summer. The variety is resistant to frost, a genetic dwarf (semi-dwarf) that will only reach about 15' tall (somewhat smaller than Nonpareil). genetic dwarf and will only reach about 15' tall (about 4.5 meters).

Asexual reproduction of Independence was performed by budding to Nemaguard Rootstock which is an excellent peach and stone fruit rootstock that is highly resistant to root-knot nematode. Reproductions run true to the original tree.

Nut characteristics

Independence produces nuts which are of high-quality with medium thickness. The nuts have a light color. Their kernels comprise 65% of the nut and are in a moderately sealed paper shell.

Independence nuts are ready for knocking (shaking down from the tree) one week before Nonpariel. The harvest maturity for knocking, (shaking the nuts from the tree).

The nuts release from the tree readily (if nitrogen is applied with proper timing). This is another reason why growers are enthusiastic about the variety: only one shaking and one harvest is enough.

Differences from seed parents

  • In comparison to its seed parent All-in-One' Almond, the new variety blooms earlier by 8–10 days and matures earlier by approximately one week.
  • In comparison to its pollen parent (21G8), the new variety has nuts with soft shells compared to a hard shells and blooms earlier by approximately 10–14 days.

Optimizing yields

Introduced in 2010, Independence variety is relatively new. With each passing year, this variety is better understood by growers in different regions. As an interspecific descendant, grafting and when to apply nitrogen can have important effects in the output of Independence trees.

Nitrogen timing

According to Harbir Singh [2], Northern California sales representative for Dave Wilson Nursery, the initial stick-tight problem and difficulty of shaking and removing the nuts experienced in the early days of Independence are now resolved.

Timing of nitrogen turned out to be critical in this regard and applying the bulk of nitrogen for the season early seems to reduce stick-tight.

Growers should not apply nitrogen:

  • After April in the southern and central production areas
  • After May 15 in northern area

There is no need to limit other nutrients.

Grafting onto hybrid rootstocks

When grafted onto standard-sized rootstocks such as Nemaguard, Lovell, Atlas, Viking or Krymsk 86, Independence trees tend to grow smaller than Nonpareil. When grafting to such rootstocks, it's best to plan for a smaller spacing than traditional Nonpareil spacings to maximize the yield potential.

Growers that are aiming for larger trees should note that Dave Wilson Nursery achieved growing larger Independence trees by grafting onto hybrid rootstocks, such as Hanson.

According to Jereme Fromm, Dave Wilson Central California sales representative, depending on growing region, soil type, and equipment, plantings average about 21 by 15 feet or 140 to 160 trees per acre.

Wait until third leaf

And depending on those factors as well as fertility, Independence trees may begin bearing a crop during the second leaf. But Singh said growers would be wise to remove the crop and wait until third leaf to let the trees funnel more energy into building a stronger architecture and taller tree. In addition, two-leaf trees aren’t sturdy enough to take mechanical shaking, and growers who do so risk permanently damaging the tree.

Independence almond nut. (Image source: Almond Board of California )

[1] Interspecific almond tree named ‘Alm-21’ (Independence) patent: https://patents.google.com/patent/USPP20295P2/en

[2] Self-Fertile Almonds Gain in Popularity: Weighing the Risks and Rewards of Self-Fertile Almond Varieties https://www.wcngg.com/2020/05/14/self-fertile-almonds-gain-in-popularity/

[3] 48 Different Almond Tree Varieties https://www.progardentips.com/almond-tree-varieties/

[4] https://www.davewilson.com/growers/products/nut-trees/almond/independence_alm-21_cv/