124 carrot varieties were showcased at the 2024 Kern County Carrot Variety Trial. (Photo: Natalie Willis/Valley Ag Voice)

By Natalie Willis, Reporter, Valley Ag Voice

In June, the University of California Cooperative Extension in Kern County hosted the annual potato and carrot variety trials offering insights into the latest advancements in crop breeding and the adaptability of varieties to Kern County’s unique climate.

Piles of potatoes were showcased at Hart Memorial Park through the collaborative efforts of UCCE and the California Potato Research Advisory Board. The potatoes were rated by marketability, total yield, and overall response to Central Valley conditions.

The Potato Trial Field Day featured a diverse array of potato varieties, each bred for specific traits such as disease resistance, yield potential, and adaptability to various soil and climate conditions. The field day provided an opportunity for farmers to observe these varieties closely and discuss their performance with UC researchers.

While this is an annual event, it can take up to 10 years for promising varieties to take root in the valley as extensive pre- and post-harvest research is explored and broad-based adaptability is measured.

According to Jaspreet Sidhu, vegetable crops farm advisor at UCCE, breeders are tasked with making certain selections for a variety over multiple years in order to determine its overall viability in the region.

“Sometimes they incorporate one thing, one gene into it, and the other one is offset…so they have to make selections really well for [roughly] five to seven years,” Sidhu said. “And then you have to trial in the lab and under small conditions and then you have to trial it into the field.”

For potatoes, a variety’s performance is inspected by multiple factors such as yield, tuber size, color, skin, and disease resistance. Fingerling potatoes have remained popular among growers with similar favorability carrying over into this year’s trial.

A field in Grimmway Farms was utilized for the carrot trial where common standard carrot varieties were grown alongside newly released and potential new carrot varieties. This year, 104 carrot varieties were displayed from various seed companies such as Bejo, IFS, Seminis, and Nunhems. Grimmway Farms had 14 varieties, five of which were Cello — a high-value variety.

Carrot varieties are evaluated based on shape, size, color, texture, and taste. Sidhu noted that varieties grown in Kern County may have differences in these aspects than other areas with different water, soil, and pest management.

The U.S. Department of Agriculture also showcased its varieties at the event, with Phillipp Simon, research leader for Vegetable Crops Research at the USDA, explaining that breeding for disease resistance is a priority.

Cavity spot is one of the most common diseases in carrots — a disease that causes small legions on carrot roots, reducing their quality and making them unsalable — but purple carrots are largely resistant to it.

“And that’s something that we still don’t fully understand, but pretty much any purple carrot automatically has cavity spot resistance,” Simon said.

While one feature of the field day is to have varieties that are ready for the current industry, growers, and seed companies, it also provides an opportunity to look into non-typical carrots and features such as disease resistance which can be carried over through additional research trials.

Another area of research in carrots explores the potential for nematode resistance which is critical for improving marketable yield and quality, especially in areas prone to nematode infestations.

“Nematodes are a big problem, especially for carrots,” Sidhu said. “It doesn’t harm the yield or anything, but when you see those balls and the nodes in the carrot, it’s the aesthetic value, and you lose the marketable yield.”


Growers in the Central Valley can benefit from the resources UCCE provides, specifically farm calls and sample diagnostics. Sidhu explained that the service is free of charge.

“If they have any problem with the veg crops, they see any disease, they see any pests. They can always call me,” Sidhu said.

Sidhu can be reached at the UC Cooperative Extension Kern Office, and contacted at (661) 304-8870 or jaksidhu@ucdavis.edu.

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