Regional Hybrid Broccoli Trials Provide a Means to Further Breeding Efforts of This Increasingly Important Vegetable Crop

A Coordinated Agricultural Project (CAP) entitled “Establishing an Eastern Broccoli Industry” is funded under the Specialty Crop Research Initiative (SCRI), and a primary component of the project is a system of regional hybrid broccoli trials conducted along the eastern seaboard.   Hybrids currently input into the trialing system originate from three private seed company and three public institution breeding programs and include intra- and inter-program crosses.   The entrance point into the system is designated  Phase One and involves testing in two replicated trials at each of four regional sites in South Carolina, North Carolina, New York, and Maine.  One Phase One trial is planted at each site during an optimal season and a second during less optimal conditions (e.g., hot) that are likely to stress plants.   In all trials, hybrids are compared to standard check hybrids and given ratings for eleven quality traits to determine which entries will be promoted to additional phases.   Approximately 25% of the Phase One entries are advanced to Phase Two wherein they are planted in replicated trials at each primary site at five different times of the year from early spring through late fall.   The top two or three broccoli hybrids in Phase Two trials at a given site are advanced to Phase Three, which involves large strip trials conducted on farms of cooperating growers at various locations near each regional site.    Floret samples from heads harvested out of Phase Two trials are used to assay levels of important nutritional constituents like glucosinolates and carotenoids. This trial system is expected to identify broccoli hybrids well adapted to East Coast growing conditions and to aid breeding programs in determining which particular hybrids to release.   An added benefit of these trials is that a large body of data is generated about specific genotypes for a wide variety of economically important traits.  These data are being used to estimate heritability of and genotype by environment effects for quality traits like bead size, bead uniformity, head color, and head shape.   Other types of analyses (e.g., stability analysis) are also being explored as an avenue to better assess the adaptation of broccoli to eastern environments.