Ketner, Julie M. , Campbell, Lesley G. , Snow, Allison .
Heritability of two life-history traits in wild, crop and crop-wild hybrid radishes (Raphanus spp.).
Crops are often sexually compatible with co-occurring wild relatives and yet have dramatically different life histories. Hybridizing crop-wild populations can include more genetic variation than their parent species, which might allow them to evolve novel phenotypes. We studied the heritability of two life history traits (days to flowering and size at bolting) of weedy, hybrid and cultivated radish plants in a four-generation artificial selection experiment. Starting with Raphanus raphanistrum (wild radish) from Michigan, USA, and R. sativus (crop radish), hand pollinations were used to create three biotypes: wild, hybrid, and crop. Each biotype was subjected to three selection treatments: early flowering, large size at bolting, or a control treatment (no selection), with three replicate lineages per treatment. Individuals were selected for early flowering or large size at bolting by allowing only the earliest flowering or largest ten percent of each population to produce the next generation. We measured the realized heritability of these traits for each biotype/trait/replicate combination according to Hill's (1972) method. The heritability of flowering date was highest in hybrid (h2 =1.19) and crop biotypes (h2 =0.93) and was not significantly different from zero in wild lineages (h2 = 0.17). Heritabilities of size at bolting were not significantly different from zero in any of the three biotypes. The high heritability of flowering time in crop and hybrid biotypes suggests that natural selection could result in earlier flowering times, perhaps leading to greater weediness of these biotypes in frequently disturbed habitats. Hybridization as a result of gene flow between a crop and its wild relatives may lead to rapid evolution in some life history traits, but not others. Estimating the heritability of life history traits can lead to a better understanding of the evolutionary potential of hybridizing biotypes.
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1 - The Ohio State University, Department of Evolution, Ecology and Organismal Biology, 318 W12th Ave, Columbus, Ohio, 43210, USA
2 - Ohio State University, Department of Ecology, Evolution, & Organismal Biology, 300 Aronoff Laboratory, 318 W. 12Th Avenue, Columbus, Ohio, 43210-1293, USA
time to flowering
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM