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Title: Genetic diversity and population structure of collard landraces

Author
item Branham, Sandra
item Couillard, David
item Stansell, Zachary
item Farnham, Mark

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2015
Publication Date: 9/1/2015
Citation: Pelc, S., Couillard, D.M., Stansell, Z.J., Farnham, M.W. 2015. Genetic diversity and population structure of collard landraces. HortScience. 50:S40.

Interpretive Summary: N/A

Technical Abstract: A common vegetable grown in the southeastern U.S. is the leafy green cole crop known as collard (Brassica oleracea L. covar. Acephala var. viridis). Predominantly a fall and winter crop, collard is one of the few vegetables found in the garden during cool seasons in the Southeast. Historically, the traditional collard patch and even commercial fields were planted with unique varieties perpetuated by seed savers, and collectively, the regional diversity for this crop was probably significant through the first half of the 20th Century. Genetic erosion of this collard germplasm pool has occurred in recent decades as commercial hybrids have been adopted by both large-scale producers and home gardeners. An unknown number of collard landraces are still being perpetuated to date; however, existing landraces are in the hands of aging seed savers. From 2003 to 2007, we explored the Carolinas and other southeastern states in search of collard gardens containing traditional landraces. We obtained about 90 samples from individual seed savers during the course of the exploration. We conducted studies of the collected landraces to evaluate the phenotypic and genotypic diversity of this pool and to determine their potential collective value for use in improving collard as well as other B. oleracea crops. Genotyping studies show that the landraces extend collard genetic diversity beyond that present in current cultivars. Collard is most genetically similar to common heading cabbages, Portuguese tronchuda cabbage and Brussels sprouts. On the contrary, the kale crop, thought to be most closely related to collard, is actually more distantly related than most other cole crops. The preserved collection has also shown to express significant variability for economically important characters and should prove to be an important new source of genes for trait enhancement.