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Abstract Detail



Population Genetics

Mardonovich, Sandra [1], Tepe, Eric J. [2], Moore, Richard C. [3].

Population structure in Carica papaya in Panamá.

The biodiversity of wild relatives of crop species can be threatened by genetic introgression of cultivated traits from co-occurring cultivated varieties or feral escapees. The tropical fruit crop, papaya (Carica papaya L.), originated in Mesoamerica, where today it is both cultivated and found in disturbed natural areas where it acts as a pioneer species. Thus, papaya serves as a model to study the effects of gene flow among cultivars and natural populations of their wild relatives. Naturally occurring papaya found near the purported center of domestication in northern Mesoamerica have rounded fruit similar in size to a tennis ball. In contrast, fruit found further south resemble the larger-fruited cultivated papaya, suggesting there has been introgression of cultivated crop traits into wild populations. Small fruited papaya, though, have been reported as far south as Costa Rica, questioning this prediction. To further question this prediction we sampled the morphology and genetic diversity of natural papaya populations in Panamá, which extends beyond papaya’s hypothesized center of origin, Mesoamerica. Forty-two individuals were analyzed for qualitative (fruit shape, fruit color, etc.) and quantitative morphological traits (fruit diameter, length of mature petiole, etc.) in four regional populations in Panamá. Some populations varied significantly in morphological traits, such as leaf petiole color and leaf shape, while other traits were universally similar, such as the overall size of the fruit – small and seedy. The levels and patterns of genetic diversity were measured using 20 molecular markers in 82 samples and compared to the diversity of 14 exotic cultivars to look for signs of genetic introgression from cultivars. STRUCTURE was implemented to determine cryptic population structure, and two of the four regional populations share genetic similarities with the cultivars. This data provides more insight into the domestication history of this important fruit crop.


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1 - Miami University, Botany, 649 Erin Dr. Apt. #5, Oxford, OH, 45056, USA
2 - University Of Cincinnati, Department Of Botany, 614 Rieveschl Hall, Cincinnati, OH, 45221, USA
3 - Miami University, Biology, 212 Pearson Hall, Miami University, Oxford, Ohio, 45056, United States

Keywords:
gene flow
introgression
Domestication
crop wild relatives.

Presentation Type: Oral Paper:Papers for Topics
Session: 71
Location: Salon 6/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 1:30 PM
Number: 71001
Abstract ID:958
Candidate for Awards:Margaret Menzel Award


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