Two UC Cooperative Extension scientists have been selected as Presidential Chairs for Tree Nuts at University of California Agriculture and Natural Resources.

Giulia Marino, UCCE specialist, will be the Presidential Chair for Tree Nut Genetics and Mae Culumber, UCCE nut crops advisor, will be the Presidential Chair for Tree Nut Soil Science and Plant Water Relations, announced Glenda Humiston, UC vice president for agriculture and natural resources.

The endowed chairs will give the two scientists a dedicated source of funding for five years for their ongoing agricultural research. UC Agriculture and Natural Resources established the two $1 million endowments in 2015. Half of the funds for the endowed chairs was donated by the California Pistachio Research Board and the other half was provided by UC Office of the President.

“The California Pistachio Research Board appreciated the opportunity to create these Presidential Chairs with the dedicated flexible funding it provides the scientists,” said Bob Klein, manager of the California Pistachio Research Board. “Mae and Giulia have stellar research records, have a history of research on California pistachios, and deserved both consideration and the award of these Chairs. The Board was pleased with the previous incumbents and is now looking forward to working with both Giulia and Mae in their programs on Genetics and Soil Science/Water Relations.”

Marino, who joined UC ANR in 2020, is based at UC Kearney Agricultural Research & Extension Center in Parlier. Her research integrates germplasm preservation and evaluation with tree physiology to improve orchard system profitability and abiotic-stress resilience. She explores the interactions between cultivar-rootstock traits, soil conditions and management practices.

“The funding from the presidential chair of tree nuts genetics will allow me to evaluate the horticultural and physiological performance of some promising new scion-rootstock options stemming from the UC pistachio breeding program developed by Craig Kallsen, UCCE farm advisor for Kern County, and Dan Parfitt, UC Davis professor emeritus,” Marino said. 

“The program has the objectives of increasing the genetic diversity of the scion and rootstock cultivars used by the pistachio industry to improve grower returns and reduce its susceptibility to climate change,” Marino continued. “Rootstock projects include novel rootstocks more tolerant of boron in irrigation water, dwarfing rootstocks for higher early yields and more efficient use of pruning and harvest inputs. Scion objectives include novel scions for higher yield and trees less sensitive to inadequate winter chilling.”

One of her current research lines focuses on the characterization of low vigor cultivars and/or rootstocks to increase orchard planting density and reduce management costs in olive, pistachio and almond. She develops protocols for irrigation management based on genotype-specific physiological responses to water stress. Marino also studies the impact of saline sodic soil conditions on pistachio physiology and of low winter chill on cherry and pistachio tree and fruit physiology.

Marino earned a doctoral degree in fruit and forestry tree systems and master's and bachelor's degrees in agricultural science, all from the University of Palermo in Italy.

Culumber, UCCE nut crops advisor for Fresno and Kings counties, focuses on enhancing the sustainability and viability of nut crop production through applied research and outreach education with emphasis on soil and water conservation and reducing the impact of production practices on air quality and greenhouse gas emissions. Culumber partners with fellow UC advisors, specialists, campus faculty, growers and other industry stakeholders to find practical, sustainable solutions for issues including soil salinity, tree training and pruning, tree nutrition, and pest and disease management. 

“As Presidential Chair, I will utilize these generous funds from the Pistachio Research Board to augment my collaborative outreach extension and applied research efforts to understand 

and develop solutions to soil and water quality problems faced by pistachio growers and other nut crop producers across the San Joaquin Valley,” Culumber said.

She is collaborating on a CDFA Fertilizer Research and Education Program project that provides irrigation and nitrogen management training for certified crop advisors and growers to adopt practices that conserve water and protect water quality. She is also studying how to improve estimates of crop evapotranspiration and forecasting for major California crops for more precise irrigation. Culumber is leading research on the effects of whole orchard recycling on air quality and climate resilience, soil health, tree growth and productivity in second-generation orchards. 

Culumber earned a Ph.D. in soil science and agroecology and a master's in plant science and molecular ecology, both from Utah State University, and a bachelor's in biology from University of Wisconsin-Stevens Point.

Bruce D. Lampinen, UC Cooperative Extension integrated orchard management, walnut and almond specialist in the UC Davis Department of Plant Sciences, received the first Presidential Chair for Tree Nut Soil Science and Plant Water Relations. Craig Kallsen, UC Cooperative Extension farm advisor in Kern County who specializes in fruit and nut crops, received the Presidential Chair for Tree Nut Genetics.