Production Research

The California walnut industry’s continued investment in production research has increased the profitability of producing walnuts through:

50 Years of Research

Over $23 Million Spent

Over 200 Projects

The production research program is developing and testing technologies for the future of walnut farming. Through the Walnut Endowment at U.C. Davis an additional $2 million has been invested in the walnut breeding program to ensure the industry’s future needs. Collaborative efforts between the research community, farm advisors, growers and industry make this all possible.

Production Research Key Areas of Study

Orchard Management

Orchard management is perhaps the most encompassing field of research as it deals with several aspects of production – rootstock, new varieties, cultural practices throughout the year, water management, tree and soil nutrition, and so on. Since partnering with UC Davis more than 4 decades ago, the ongoing research has resulted in several new varieties and rootstocks that are widely used today by walnut growers. Some of the varieties include Chandler, Howard, Vina and rootstocks include VX211, Paradox, and Vlach.


Just like any other commercial crop, walnuts are also susceptible to a variety of insect pests. The entomology research focuses on identifying potentially dangerous pests for the walnut tree and ways of mitigating this pest pressure. Some of the important walnut pests are Husk Fly, Coddling Moth and Navel Orange Worm. Besides the obvious commercial aspects of managing pests, identifying and dealing with them is especially important as majority of walnuts are exported and the importing countries have regulations to prevent sale of any commodity with a potential of spreading diseases for their own local crops.

Breeding & Genomics​

Genetic improvement is perhaps the most exciting field as development in gene analysis technology leads to a better understanding of which genes control what aspects of production, harvest time, pellicle color, lateral branching, and so on. UC Davis recently announced that the walnut genome was completely mapped for the first time. What this means is that we now have a better understanding of how the tree functions and what triggers certain functions.

Plant Pathology & Nematology

The field of plant pathology deals with studying plant diseases and identifying solutions to it. These diseases could be a result of pathogens (fungi, bacteria, viruses) or environmental factors. Some of the common diseases affecting California walnuts include Botryospheria and Walnut Blight. The California Walnut Board and Commission has partnered with UC Scientists on several projects aimed at finding solutions to various diseases through a combination of strategies – suitable chemicals, improved orchard management practices or more disease resistant rootstock.
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