Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/29/2006
Publication Date: 1/12/2007
Citation: Lewers, K.S., Ashman, T., Main, D. 2007. Sex determination of strawberry genotypes: preparation for genetic mapping of sex.. Plant and Animal Genome VX Conference Abstracts, page 22. Interpretive Summary:
Technical Abstract: A resource of unusually great importance for programs developing cultivars of strawberry (Fragaria ×ananassa) is wild strawberry germplasm, F. virginiana and F. chiloensis. However, the major sources of wild germplasm are sex dimorphic species (those with male or female plants). Sex is thought to be controlled by three alleles at a single locus with female dominant over hermaphrodite (desired for cultivars), which is dominant over male (F>h>m). Selecting for high-yielding true-breeding hermaphrodites, while introgressing traits unique to wild strawberry germplasm, could proceed at a more rapid pace if genetic markers for sex were available. The overall goal of the project is to develop sex-linked molecular markers so strawberry breeders can fully utilize female and male germplasm. A population derived from a cross between an Fm individual and an hm individual would allow qualitative as well as quantitative trait mapping. Therefore, a series of testcrosses was made to identify these genotypes from among five potential Fm F. virginiana female parents and three potential hm F. virginiana hermaphrodite parents. Concurrently, mapping populations were generated for all possible combinations among these candidate parents. Meanwhile, the candidate parents also were evaluated with 94 SSR markers, of over 300 available, to identify polymorphisms. Testcross populations were evaluated for fruit set to identify the desired parents. The selected parents show polymorphisms with 44 of the 94 SSRs. The resulting mapping population was copied clonally and, following DNA extraction, was established in both a glasshouse and a field for phenotypic evaluation.