Diversity in a Collection of Heirloom Tomato Varieties

Heirloom tomato varieties are appealing because of their diverse range of color, size, shape, texture and flavor. Heirlooms are largely unimproved for traits such as yield or disease resistance; as such they have attracted efforts of breeders and other researchers who are targeting niche markets.  The National Plant Germplasm System (NPGS) Plant Genetic Resources Unit (PGRU) holds the largest tomato (Solanum lycopersicum L.) collection in the U.S., many of which are heirlooms. Characterization of the collection will increase its efficiency of use. Replicate plots of 44 heirloom varieties were grown in three locations (Ohio, North Carolina and New York) in 2009. Data were collected for highly heritable horticultural traits and several fruit component traits: ascorbic acid (vitamin C), lycopene, titratable acids and brix. We present the results of phenotypic characterization of the 44 varieties and estimate partitioning of variation and heritabilities of the fruit components.