Significant results of the study:

• All of the cultivated pepper varieties tested share a similar amount of genetic change relative to their common, although unknown, ancestor.

• Within the group of plants that produce sweet, nonspicy peppers, there was three times less diversity than within the group of pepper lines bearing pungent, or spicy, peppers.

• Of the well-defined groups of spicy pepper types, the Anaheim and ancho group are most closely related to the sweet bell pepper types.

• In general, lines with similar looking peppers were closely related. However, the two semi-wild pepper lines known to be resistant to the funguslike pathogen Phytophthora capsici have very similar peppers but are genetically distinct.

Other researchers on this UC Davis study were: Theresa Hill, Hamid Ashrafi, Sebastian Reyes-Chin-Wo, Ji-Qiang Yao and Kevin Stoffel, of the Center for Seed Biotechnology in the Department of Plant Sciences; and Maria-Jose Truco, Alexander Kozik and Richard Michelmore, of the Genome Center.

Funding for the study was provided by the University of California Discovery program, with matching funds from these firms: Rijk Zwaan BV, Enza Zaden BV, DeRuiter Seeds BV, from the Netherlands; Vilmorin Co. of France; and Nunhems USA, Seminis Vegetable Seeds Inc. and Syngenta Seeds Inc., from the U.S.