title: Seed fates in crop-wild hybrid sunflower: crop allele and maternal effects.
abstract: Domestication has resulted in selection upon seed traits found in wild populations, yet crop-wild hybrids retain some aspects of both parental phenotypes. Seed fates of germination, dormancy, and mortality can influence the success of crop allele introgression in crop-wild hybrid zones, especially if crop alleles or crop-imparted seed coverings result in out-of-season germination. We performed a seed burial experiment using crop, wild, and diverse hybrid sunflower (Helianthus annuus) cross types to test how a cross type's maternal parent and nuclear genetic composition might affect its fate under field conditions. We observed higher maladaptive fall germination in the crop- and F1- produced seeds than wild-produced seeds and, due to an interaction with percent crop alleles, fall germination was higher for cross types with more crop-like nuclear genetics. By spring, crop-produced cross types had the highest overwintering mortality, primarily due to higher fall germination. Early spring germination was identical across maternal types, but germination continued for F1-produced seeds. In conclusion, the more wild-like the maternal parent or the less proportion of the cross type's genome contributed by the crop, the greater likelihood a seed will remain ungerminated than die. Wild-like dormancy may facilitate introgression through future recruitment from the soil seed bank.
authors: Department of Horticulture and Crop Science, Ohio State University Columbus, OH, USA.
authors: Brian A
authors: BA
authors: Pace
authors: Department of Ecology and Evolutionary Biology, University of Kansas Lawrence, KS, USA.
authors: Helen M
authors: HM
authors: Alexander
authors: Department of Biology, Washburn University Topeka, KS, USA.
authors: Jason D
authors: JD
authors: Emry
authors: Department of Horticulture and Crop Science, Ohio State University Columbus, OH, USA.
authors: Kristin L
authors: KL
authors: Mercer
keywords: dormancy; gene flow; hybridization; introgression; maternal effects; seed banks; sunflower