Charles A. Mullins

‘WHT 2801' was the most productive cultivar. Plant populations, which ranged from 21,954 to 28,052 plants per acre, had little effect on plant characteristics, ear characteristics, and yields of the four sweet corn cultivars evaluated in the trial. There was only one cultivar-spacing interaction.

Processing sweet corn has increased in acreage in west Tennessee in recent years. The crop is fully mechanized and kernels are cut from the ear in the field. High production levels are needed, and closer plant spacing generally have been effective in increasing yields of sweet corn. Ear size is not a major concern in processing sweet corn as long as the harvesters can be efficient in removing kernels from the ear. The harvesters are set at 30 inch row spacing so in-row spacing is the only factor that can be used effectively to manipulate plant population. Cultivars vary in plant vigor, and efficient spacings may vary with differences in plant vigor and growth habit. Early maturing cultivars often have weak plant growth characteristics. An experiment was conducted at the Plateau Experiment Station at Crossville, TN in 2000 to evaluate performance of four processing type sweet corn cultivars at four plant populations.

The site was prepared for planting using conventional tillage in late April. Fertilizer was broadcast at 600 lb/A of 15-15-15 before final disking on May 3. Plot size was one row, 20 ft long, and rows were spaced 30 inches apart. Seed of selected cultivars was obtained from commercial seedsmen, and was planted on May 4. Seeding was by hand at the selected spacing and two seeds were planted per hill. Experimental plot design was a split plot with four replications. Herbicides applied on May 5 were atrazine (Aatrex) at 1.0 lb ai/A and metolachlor (Dual II) at 2.0 lb ai/A. Plots were thinned to one plant per hill on June 30. Esfenvalerate (Asana) at 0.05 lb ai/A was alternated with lambdacyhalothrin (Warrior T) on a 4 to 5 day frequency starting at first silking.

Plots were harvested when kernels were near 73% moisture. Records taken on plant characteristics included number of plants per row, height, diameter, and ear height. Records taken on harvested ears included yields in number and weight, average ear weight, ear length, ear

diameter, and % ear fill. A sample of 6 ears per plot was selected and the kernels were cut from the cob. The kernels were weighed and a 30 gram sample was oven dried at 69 degrees C for 48 hours. Samples were reweighed and percentage moisture was calculated. Grain (cut corn) yield was adjusted to 73% moisture.

Plant stand was not different due to cultivar (Table 1). Plants of ‘GH 2547' were taller and ears were set higher above the ground than all other cultivars. Yields in number of ears per acre were not different due to cultivar. ‘WHT 2801' had a higher yield in tons of ears per acre and a heavier ear than all other cultivars. The actual plant population was not at the targeted plant population. Plant population was higher than desired at the 19,000, 22,000, and 25,000 plants per acre. However, desired stand and actual stand were the same at the 28,000 plant population. Although exact targeted populations were not reached, the population had a rather desirable range for the study on population effect. Population had no effect on plant height, plant diameter, ear height, yield or average ear weight.

‘Rival’ had shorter ears than all other cultivars (Table 2). ‘GH 2547' had a smaller ear diameter than all other cultivars. ‘WHT 2801' had a higher grain yield than all other cultivars after adjustments were made for moisture. ‘Bonus’ had a higher percentage ear fill than ‘GH 2547'. Population had no effect on any characteristic measured. The adjusted grain yield tended to increase as population increased, although differences were not significant. The only significant cultivar-spacing interaction was for ear diameter.

Table 1. Plant characteristics and yield of processing sweet corn cultivars evaluated at different spacings at The University of Tennessee Plateau Experiment Station at Crossville, 2000.