Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 5/22/2008
Publication Date: 7/15/2008
Citation: Farnham, M.W., Bjorkman, T. 2008. Development of Broccoli Adapted to Summer Conditions in the Southeastern United States. HortScience. 43:1152.
Interpretive Summary: Not required.
Technical Abstract: For over ten years the USDA-ARS broccoli breeding and genetics project at the U.S. Vegetable Laboratory (USVL) in Charleston, South Carolina has conducted a breeding program in which broccoli has been selected for adaptation to summer environments. The program was initiated in the early 1990s using a few commercial hybrids available at that time that showed some potential for head production under summer conditions and other noncommercial broccolis obtained from other sources. The program uses a conventional pedigree breeding approach in which different inbreds are crossed to one another to form hybrids that are subsequently selfed to create segregating populations. Through several rounds of selection and recombination, lines increasingly adapted to hot and humid summer conditions at Charleston have been identified. These USVL summer broccoli lines appear to be different than any broccoli lines designated as “heat tolerant” developed by western U.S. breeding programs. Western broccoli is generally selected under hot day/cool night conditions, while USVL lines have been selected under hot day/hot night conditions. Field studies conducted at different locations and times of the year indicate that USVL lines adapted to southeastern summer conditions perform very similar regardless of the temperature conditions they are grown in. On the contrary, western broccoli lines perform well under optimal temperature conditions (e.g., in the autumn), but do not head at all or only produce very poor quality heads in summer. These observations lead to a hypothesis that the USVL broccoli is different than western “heat tolerant” broccoli. The USVL broccoli might be more accurately designated “heat resistant” or “heat insensitive”.