Recent Topics Posters
Chang, Hsiaochi , Snow, Allison , Campbell, Lesley G. .
A test for crop traits linked to a reciprocal translocation of cultivated and wild radish: implications for weed evolution following hybridization.
Wild and cultivated radish (Raphanus raphanistrum L., R. sativus L.) represent a model system for studies of crop-wild hybridization and introgression. We investigated possible evolutionary effects of a reciprocal translocation that causes low pollen fertility in a heterozygous state, as occurs in F1 crop-wild hybrids, due to problems with meiosis. Specifically, we tested for associations between low pollen fertility and two crop-specific traits, later flowering and lack of fruit abscission, using BC1 progeny (wild x [wild x crop]). We expected that some BC1 plants would have both translocation regions from the crop, resulting in low pollen fertility (similar to F1 plants), while others would have one or neither region from the crop. We used low pollen fertility to test for presumed linkage between one of the crop translocation regions and crop-specific traits. Wild genotypes came from Pellston, Michigan, and crop genotypes came from four common cultivars. Data were obtained from a total of 472 BC1 plants and 19 wild plants grown in container pots in a greenhouse (randomized block design). As expected, BC1 plants had lower pollen fertility and flowered later than wild genotypes, although many BC1 plants were similar to wilds. Most BC1 plants (~81%) shed their fruits at maturity. Lower pollen fertility in BC1 plants was correlated with delayed flowering in the four cultivar groups, and this correlation was strongest in progeny from the Cherriette and Scarlet Globe cultivars. Regarding fruit abscission, BC1 plants with the crop trait (lack of abscission) had similar pollen fertility to BC1 plants with the wild trait, suggesting that genes for fruit abscission are not tightly linked to the translocation regions. We conclude that as introgression proceeds following episodes of hybridization, natural selection against low pollen fertility and/or late flowering could act in concert to purge genes in the crop-specific translocation region.
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1 - The Ohio State University, Evolution, Ecology and Organismal Biology, 318 W. 12th Avenue, Columbus, OH, 43210, USA
2 - Rice University, Ecology and Evolutionary Biology, 6100 Main Street, Houston, TX, 77005, USA
Presentation Type: Recent Topics Poster
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM