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ARS Home » Southeast Area » Charleston, South Carolina » Vegetable Research » Research » Publications at this Location » Publication #310060
Title: Increasing plant density in eastern United States broccoli production systems to maximize marketable head yields

Author
item WARD, BRIAN - Clemson University
item SMITH, P - Clemson University
item JAMES, S - Clemson University
item Stansell, Zachary
item Farnham, Mark

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2015
Publication Date: 7/1/2015
Citation: Ward, B., Smith, P., James, S., Stansell, Z.J., Farnham, M.W. 2015. Increasing plant density in eastern United States broccoli production systems to maximize marketable head yields. HortTechnology. 25:330-334.

Interpretive Summary: Eastern environments do not have conditions conducive to broccoli production much of the year, but most areas have a specific season (e.g., late fall in South Carolina or late summer in upstate New York) when market-quality broccoli heads can be produced. However, there is a need to establish systems to optimize broccoli yield and quality from eastern productions and to increase the likelihood of producing a competitive crop. Thus, ARS scientists at Charleston, South Carolina, in cooperation with scientists at Clemson University have been working to determine the best methods to use in maximizing broccoli yield and quality and to increase the likelihood of producing a competitive crop. These scientists conducted three field studies in South Carolina in the fall of 2012 and 2013 and evaluated the effect of variable plant densities ranging from about 25,000 plants per acre up to about 100,000 plants per acre on harvested heads. They showed that weight and quality characteristics of heads were not generally affected by the variable densities, but they did demonstrate that the highest marketable yields were measured using the highest plant densities. Results indicated that eastern producers can increase populations compared to what they previously used in order to maximize yield. These findings provide useful information for eastern vegetable growers and extension agents who advise them.

Technical Abstract: Increased demand for fresh market broccoli (Brassica oleracea L. var. italica) has led to increased production along the eastern seaboard of the United States. Maximizing broccoli yields is a primary concern for quickly expanding eastern commercial markets. Thus, a plant density study was carried out in the fall of 2012 and 2013 using the hybrid cultivar ‘Emerald Crown’ on a commercial farm in Summerton, SC, and in the fall of 2013 using ‘Emerald Crown’ and another hybrid ‘Durapak 19’ on a research farm in Charleston, SC. The objective was to determine the effect of variable within-row spacings of 10.2, 15.2 and 20.3 cm (employing a system with double rows spaced 30.5 cm apart) on marketable yields and quality in the three environments. Results from this study indicated that increasing plant density by reducing within-row spacing to 10.2 cm, significantly increased overall yield•ha-1over the 15.2 and 20.3 cm spacing treatments in two of four comparisons. Stem diameter and average head weight were unaffected by plant density; however, heads harvested from plots with the highest plant densities exhibited significantly lower bead uniformity in the Summerton 2012 trial, and significantly larger bead size in the two trials conducted in 2013. In general, the highest total marketable yields were obtained using the 10.2 cm within-row spacing, but increased competition at the highest density may increase the risk of plants producing lower quality characteristics. Yield and head quality attributes may be optimized at the 15.2 cm within-row spacing.