Walnut Scion & Rootstock Improvement
Walnut Scion & Rootstock Improvement
Walnut Scion & Rootstock Improvement
University of California
Walnut Scion & Rootstock Improvement

Evaluation

Field Evaluation

Evaluation in the field includes phenological traits such as leafing, flowering and harvest dates. Other traits include precocity, lateral bearing, yield, tree form and blight resistance.

Fig. 4. Nuts borne on lateral branches.
Fig. 4. Nuts borne on lateral branches.
Fig. 5. Symptoms of walnut blight.
Fig. 5. Symptoms of walnut blight.

Nut & Kernal Evaluation

Nut and kernal evaluations are based on weight and a combination of traits:

  • Kernal traits: color, weight, kernal percent, fill, shrivel, plumpness, ease of halves.
  • Shell traits: seal, thickness, color, texture

Fig. 6. Harvested nuts.
Fig. 6. Harvested nuts.
Fig. 7. Measuring  & recording nut weight.
Fig. 7. Measuring & recording nut weight.
Fig. 8. Evaluation of kernel traits.
Fig. 8. Evaluation of kernel traits.

Grower Field Trials

The input from growers is an essential aspect of the Walnut Improvement Program, including field trials and extension events.

Fig. 9.  Gale McGranahan with colleagues in the field.
Fig. 9. Gale McGranahan with colleagues in the field.
Fig. 10. Growers inspect nuts during field trial.
Fig. 10. Growers inspect nuts during field trial.
Fig. 11. Growers participate in nut evaluation.
Fig. 11. Growers participate in nut evaluation.

 

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