The 2011 ASHS Annual Conference

The primary goal of this study was to determine the best planting density with a current, commercially grown cultivar in the southeastern US which resulted in the best yield. Planting was 12 May 2010 with ‘Lafayette’. Treatments were replicated four times on a commercial farm in North Carolina. Spacing between row centers was 76 cm and plot length 18.3 m which was divided into three 6.1 m subplots. An initial seeding rate of 360 thousand plants/ha (THPH) was used and the 4-row plots were thinned at the 1 to 2 true leaf stage to 8 planting densities which ranged from 74 to 346 THPH. Harvest began when plots contained fruit that reached grade 4 (oversize fruit). First harvest was 12 July, 45 days after planting (DAP). A second and third destructive harvest was made 46 and 47 DAP. To simulate once-over harvest, plants from the middle two rows in the subplots were pulled by hand. All fruit, grade 1 and larger, were removed from the plant and graded into marketable grade (1, 2 and 3), and cull grades (grade 4; misshapen). Fruit in each grade were weighed and counted. Marketable and total yields for the first destructive harvest were similar for planting densities between 74 to 247 THPH, while yields were depressed with higher planting densities (296 and 346 THPH). No planting treatment had more than 3% oversize fruit. The percentage grade 1 fruit for the lowest planting density (74,000 THPH) was 6%. At the highest planting densities (296 and 346 THPH) grade 1 fruit averaged 20%. Conversely, the percentage grade 3 fruit for the low planting density was 42% and 22% at the high planting density. Total marketable fruit for the populations that ranged from 74 to 247 THPH was 9.0 to 10.1 MT/ha, while at 296 and 346 THPH marketable yields were 7.7 and 5.3 MT/ha, respectively. When harvest was delayed two days, marketable yields increased about 35%. Percentage grade 3 fruit increased regardless of planting density and averaged a 20% increase from the first/early harvest while the percentage of oversize fruit averaged 6% across planting densities. Number of fruits per plant decreased as planting density increased (2.1 to 0.4 fruit per plant). Yields were similar when planting densities ranged from 74 to 247 THPH. There is the potential to save money if planting densities can be reduced yet similar yields obtained which occurred in this initial study.