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Title: North American Continent – A new source of wild Lactuca spp. germplasm variability for future lettuce breeding

Author
item LEBEDA, A - Palacky University
item DOLEŽALOVÁ, I - Palacky University
item KITNER, M - Palacky University
item NOVOTNÁ, A - Palacky University
item ŠMACHOVÁ, P - Palacky University
item Widrlechner, Mark

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2011
Publication Date: 2/22/2012
Citation: Lebeda, A., Doležalová, I., Kitner, M., Novotná, A., Šmachová, P., Widrlechner, M.P. 2012. North American Continent – A new source of wild Lactuca spp. germplasm variability for future lettuce breeding. Acta Horticulturae. 918:475-482.

Interpretive Summary: The world's genebanks have serious gaps in their collections of wild and weedy species of lettuce (Lactuca), which may possess many valuable genes for lettuce improvement. Between 2002 and 2008, a series of seed collection trips took place in the USA and Canada to search for wild and weedy lettuce species. Altogether, 16 states (Arizona, California, Colorado, Idaho, Iowa, Minnesota, Montana, Nevada, New York, North Carolina, Oregon, South Dakota, Utah, Washington, Wisconsin and Wyoming) and two Canadian provinces (Ontario and Quebec) were visited. Through these trips, seven different wild and weedy lettuce species, along with an interspecific hybrid and one undetermined species were observed and collected in 200 locations. In this paper, we present data on the geographic distribution and biology of lettuce species naturally occurring in North America. We also assessed North American samples of prickly lettuce (L. serriola), the most widespread weedy species, for variation in pigmentation and plant architecture during seed regeneration, and also conducted laboratory analyses of DNA for Amplified Fragment Length Polymorphisms (AFLPs) and absolute DNA content. Our analyses revealed considerable variation in plant phenotypes. And although prickly lettuce samples originating from various regions differed significantly in their AFLPs, we observed little variation in their absolute DNA content. This germplasm has been incorporated into the Lettuce Working Collection conserved by the Botany Department at Palacký University in Olomouc, Czech Republic, and it is now being employed for scientific research and crop improvement. The results presented in our report should be useful for researchers studying lettuce genetics and to plant breeders involved with germplasm enhancement and the development of improved lettuce cultivars.

Technical Abstract: In the years 2002-2008, missions were undertaken in the USA and Canada to search for wild and weedy Lactuca species. Altogether, 16 states in the USA (Arizona, California, Colorado, Idaho, Iowa, Minnesota, Montana, Nevada, New York, North Carolina, Oregon, South Dakota, Utah, Washington, Wisconsin and Wyoming) and two provinces in Canada (Ontario and Quebec) were visited. In total, seven wild and weedy Lactuca spp. (L. serriola, L. saligna, L. virosa, L. canadensis, L. biennis, L. floridana, and L. ludoviciana), an interspecific hybrid (L. canadensis x L. ludoviciana), and an undetermined Lactuca species were observed and collected in 200 locations. In this paper, we present new data on the distribution and ecobiology of Lactuca naturally occurring in North America. Morphological assessment of L. serriola samples acquired from North America revealed considerable intraspecific phenotypic variation. Although L. serriola samples originating from various eco-geographical regions differed significantly in their genetic polymorphisms (based on AFLP markers), we observed little variation in their absolute DNA content.