LSU AgCenter Broccoli Variety Trials 2013-2015

Kathryn Fontenot  |  6/22/2017 4:13:05 PM

Table 2. Broccoli Yields

Broccoli Field

Table 1. Broccoli Germination Rates

Introduction

The 2014 LSU AgSummary reported 8,246 acres of vegetables grown commercially. Of those acres, 59 were dedicated to broccoli production. The total gross farm value of vegetable crops (2014) was $76.1 million with $515,313 from broccoli sales. Although broccoli is not one of the top vegetable crops grown in terms of number of acres or sales in Louisiana, production continues to be steady among market growers. Louisiana producers direct-selling their crops at farmers markets note customers prefer a variety of vegetables and fruit at individual stands. Producers can sell both the main heads individually and the side shoots packaged in 1-pound clam shells or side shoots by the pound. As per conversation with Louisiana growers, broccoli is typically sold by the head from anywhere from $1.50 to $3 depending on size. 

Growing Practices

Twenty-one varieties of broccoli were grown over two growing seasons (2013-14) and (2014-15) at the LSU AgCenter  Botanical Gardens at Burden in Baton Rouge. Varieties were tested for total yield and marketable yield (USDA standard grades) of main heads. Disease and insect occurrence were simply noted. All varieties were seeded into 72-count plug trays 5 weeks prior to transplanting. 

Peters 20-20-20 (200 ppm rate) was used to fertilize seedlings weekly from first true leaf until transplanting. Both seasons the seeds were sown in early August, and plots planted in late September. Germination rates were calculated for all varieties both years. The field was fertilized with 750 lbs of 13-13-13 per acre prior to planting. Drip irrigation and black plastic mulch were installed. Simazine (1.5 pts/acre) and Goal (1 pt/acre) were applied as pre-emergent herbicides to row middles prior to planting. As needed, foliar applications of Admire Pro for aphid control (1.3 oz/acre) and Radiant (6 oz/acre) for worm control were made. During the growing season CaNO3 at 22 lb/field/week for three weeks (40 lbs N/acre rate) was injected through the drip irrigation to fertigate the plants. A foliar application of Solubor at a rate of 1 lb/acre was also made. 

All broccoli was planted in a randomized complete block design with three reps of each variety. Broccoli was double-drilled on 12-inch centers with 20 plants per replication on 48-inch-wide rows. In 2013-14,  broccoli was harvested from November 18 through January 3. In  2014-15, broccoli was harvested from November 13 through December 30. All harvests occurred within 100 days of transplanting, after which it was determined that producers would need to prep the field for spring crops. Therefore, the study was terminated. 

Results 

Germination Rates: Germination rates of all varieties were acceptable in 2013-14 with the exception of Coronado crown. Germination rates of all varieties decreased in the 2014-15 season with the exceptions of  Packman, Expo and Belstar, which increased. New trays and inserts were used and the growing medium was the same, Sunshine Mix #1,  for both seasons. Fresh seed was ordered both seasons. Weather conditions were similar during both seeding periods. During August 2013 the high temperature was 96 degrees F, low temperature was 66 degrees F, and  mean temperature was 82 degrees F. Approximately 3.4 inches of rain fell in August 2013. In August 2014, the temperatures were very similar with a max temperature of 96 degrees F and a minimum temperature of 65 degrees F; the mean temperature was 83 degrees F. Approximately 5.6 inches of rain fell in August 2014. Seeds were germinated in a shade house structure open to environmental conditions. 

 Broccoli was evaluated for total yield, marketable yield and earliness in maturity. Louisiana producers prefer an early crop as the early crops command a higher price at the beginning of a season. 

Maturity Early producing varieties in 2013-14 included Amadeus, Bluewind, Castledome, Southern Comet, Everest and Packman. Early producing varieties in 2014-15 included: Bluewind, Everest, Castledome and Packman. 

Yields Field plot work for universities is small. Instead of reporting the total number of heads harvested within the trial, the total number of head per acre were calculated based on LSU AgCenter yields, allowing producers to make an accurate assumption of what their field plots might yield. Caveat: Yields have a potential of greatly differing in various soil types, under various weather conditions, insect and disease pressures and by variety. An acre plot in this trial is assuming a producer plants the entire acre with no skip rows or guard rows. The top-yielding and marketable-yielding varieties are listed in table 2. 

A varietal preference among Louisiana producers is Packman; therefore, it is listed in blue along the top row in Table 2. In the 2013-14 growing season Packman was the top-yielding variety by less than 300 heads per acre. However, during the first growing season, Packman only produced 75% marketable yields. In the second growing season (2014-15), Packman was not the top-yielding in terms of  number of heads per acre but had 100% marketable yields. In both growing seasons, Everest and Green Magic were among the four top-yielding varieties, and both of these varieties had acceptable (≥81%) marketability. 

Conclusions: Based on the results of both growing seasons, Louisiana commercial producers should consider adding the varieties Green Magic and Everest to their broccoli fields. Packman continues to be a high-yielding variety but cannot contend with the other two in terms of yield combined with percent  marketability. Additionally, Everest was noted as an early producer in both growing seasons. Percent marketability was determined by using USDA grading standards that include stem length, diameter, crown width, bead size and overall crown uniformity, color and presence of disease or insect incidence. Amadeus yields were notably lowered as it was very susceptible to rot in the field. All varieties were treated for worms and aphids, but none suffered severe injury from insects or disease (exception Amadeus – rot) in either growing season. All harvests ceased after 100 days after transplanting in the field, as most commercial producers would need to prepare their fields for a spring crop past that point.
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