| Abstract Detail
Conference Wide Graham, Elaine [1], Pertuze, Ricardo [2], Jones, Carl [1], Chetelat, Roger [1]. Genetic diversity and crossing relationships of Chilean tomatoes. THE four wild tomatoes native to Chile – Lycopersicon chilense, L. peruvianum, Solanum lycopersicoides, and S. sitiens – each exhibit unique ecological adaptations and traits of interest to breeders. The TGRC organized collecting trips to N Chile in 1986-1988, 2001, and 2005. The new accessions greatly expand ex situ collections of each species, and provide a thorough sampling of populations across their entire geographic ranges. Self-pollination tests indicated all accessions are self-incompatible, except for a self-compatible biotype of L. peruvianum at the S limit of its distribution, and a mixed SC / SI population of L. chilense at the SE margin. Using seed collected in the wild, genetic diversity -- both within and between populations -- was estimated for L. chilense and L. peruvianum with SSRs and allozymes. Diversity within populations of L. chilense was highest in the center of its distribution, and partially depleted on the margins. The L. chilense populations had lower levels of genetic diversity than the L. peruvianum populations. Genetic divergence between populations was correlated with geographic distance, suggesting some isolation-by-distance. Experimental cross-pollinations between L. chilense populations revealed partial reproductive failure between accessions located on the N / S margins of the distribution and those in the central region. Partitioning of genetic distances into three groups based on crossing tests (N, S, Central) explained approx. 25% of the total molecular variation. The marginal populations were also morphologically distinctive, suggesting the existence of at least three races or subspecies. Crosses between L. chilense and sympatric L. peruvianum, S. sitiens, or S. lycopersicoides populations failed, indicating strong interspecific reproductive barriers. However some allopatric L. peruvianum accessions from N Peru were partially compatible with L. chilense. These results are discussed in the context of the ecology, utilization, and conservation of Chilean tomatoes.
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1 - Univ. of California, Dept. of Plant Sciences, C.M. Rick Tomato Genetics Resource Center, Davis, CA, 95616, USA
2 - Univ. de Chile, Dept. de Prod. Agric., Casilla 1004, Santiago, , Chile
Keywords:
genetic diversity
crossing relationships.
Session: Poster-130
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM
Abstract ID:287 |
