Variety traits

Maturity Group — Walnut

Juglans regia L.

There is no strict classification of maturity groups for walnuts; maturity is determined by visual and physical indicators, such as husk splitting and the browning of the internal septa.

In the reference 63 varieties crop Persian walnut, where this is mentioned in the description.

Technical maturity of the walnut occurs when the green husk splits and the nuts begin to drop spontaneously. An important internal indicator of readiness is the browning of the septa between the kernel and the shell, with the moisture content of the nut reaching up to 40 percent at the time of harvest.

Cultivars are classified as early, mid-season, or late based on the accumulated growing degree days (GDD) requirement, which is approximately 2000 degrees. Early harvesting of immature nuts leads to a reduction in commercial quality due to kernel darkening and shriveling during drying, while late cultivars require a prolonged frost-free period to complete their development cycle.

A separate phase is the milk-waxy stage, where nuts are harvested for industrial processing before the shell has formed. Unlike commercial harvesting, this stage is characterized by a soft husk and does not require the seed to reach biological maturity.

General information about the subject — on the page Maturity group.

Sources8

Varieties of Persian walnut mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.