In the 1960s, California sweet potato growers faced a serious problem with russet crack disease of sweet potatoes.  This disease, caused by a severe strain of sweet potato feathery mottle virus (SPFMV), can cause root lesions, internal root corking symptoms, and reduced yields. Scientists at the University of California developed a program to provide growers with virus-tested, true-to-type sweet potato seed stock.  Dr. George Nyland and Dr. Robert Campbell of the UC Davis Plant Pathology Department managed the program for many years.

  In 1995, following the retirements of Dr. Nyland and Dr. Campbell, the program was transferred to FPS. The FPS program houses a collection of sweet potato mother plants as large, potted plants in a greenhouse.  These plants originated from vines which were treated by tissue culture therapy to eliminate viruses, tested negative for viruses, and were subsequently evaluated for agronomic characteristics. The tissue culture therapy and virus testing is done by FPS. Agronomic testing is arranged by sweet potato clientele and University Extension.  Bob Scheuerman and Bill Weir, emeritus farm advisors from Merced County, have each played a key role in leading the horticultural evaluations, as does current sweet potato form advisor Scott Stoddard.

  The collection is supported by the Sweet Potato Council of California, the Livingston Farmers Association, and individual sweet potato growers. Plant material is distributed as small rooted plants or unrooted cuttings to members of the sponsoring organization or with permission of the sponsor.