National yield and chipping trials, funded by the U.S. Potato Board (USPB) and managed by the Snack Food Association, were conducted by growers, processors and university researchers in six states in 2004. These trials evaluated 10 advanced breeding lines with excellent chipping potential from seven U.S. potato breeding programs.

The trials involved collecting information, including yield stability, specific gravity (dry matter level), tuber and chip defects, and disease and pest susceptibilities or resistances. Lines were evaluated for chipping ability directly from field harvest and also from short- and long-term cold storage. However, the most important product of these trials is that they facilitate the exchange of information and foster coordinated efforts between growers, processors, extension and researchers.

At each trial location, the regional coordinator selects the cooperating chip grower and a cooperating chip processor (Table 1). These trials are designed to simulate a mini-commercial trial, when growers plant seed of each entry in one of their fields and manage it with standard commercial cultural practices. At harvest, samples are graded for yield, size distribution, defects and dry matter.

The potatoes also are chipped within 48 hours to evaluate out-of-the-field processing characteristics. In the northern trial locations, where potatoes are typically stored for four to eight months, samples are placed in grower storages for out-of-storage chipping evaluation the following late winter or early spring.

Potatoes are much more site-specific in their range of environmental adaptation than they appear. Lines often perform significantly better in the region where they were first selected by the breeding program which developed them. Only a few potato varieties, such as Atlantic, consistently perform well over a wide range of geographical and environmental conditions. Thus, the Atlantic variety is used in our SFA/USPB Chip Trials as a standard for stable yield and high dry matter.

High specific gravity (dry matter) is a very important trait for processing potatoes. The higher the dry matter, the less heat and frying oil it takes to make chips and also the higher the conversion ratio of finished product from fresh product. However, potato lines with higher dry matter are often much more susceptible to tuber bruising, resulting in increased defects in the finished chips. Disease, such as scab or soft rot, also impact tuber quality. Potato varieties also differ in their ability to make light-colored chips, either processed directly from field harvest or from storage.

The goal of these trials is to identify new potato lines with the best combination possible of the above-discussed traits. Notes on the 10 lines tested in 2004 are provided in Table 2 along with identification of the breeding program that developed them.

The naming and release of a new potato variety does not assure that it will survive the critical test of meeting “commercial acceptance” by the industry. Because initial line selection and development involve small-scale, often individual-handheld procedures, it is difficult to select for traits that might be impacted by large-volume agriculture.

When a new variety is subjected to the more rigid tests of large-scale production, including mechanical seed cutting, planting, harvesting, handling and long-term storage, significant defects — if they exist within the variety — are more likely to appear. Also, to ensure a more rapid and successful adoption, research must be conducted on optimal production practices, such as fertilization, spacing or storage temperatures, specific for each new line. Thus it is very important to have industry involvement as early as possible in variety development, as exemplified by the USPB/SFA Chip Trials.