The experimental design at each location was a randomized complete block of each maturity group, with 3 replications of each entry. Plots were 4 rows 30 inches wide and 20 feet long. Ends of plots were trimmed to a uniform length 3 to 4 weeks after emergence. Cultural and pest control practices for optimum yields were followed. Plots were limed and fertilized on the basis of an annual soil test. All seeds were treated with Vitavax 200 fungicide prior to planting. Only herbicides currently registered for use on soybeans were used in these studies, with strict adherence to all label instructions.
Planting Rate...Seed of all private entries were supplied by the participating companies. All seeds were packaged for planting at the rate of 7 seeds per foot of row. Plots were planted with a cone planter.
Yield...An Almaco SPC-20 plot combine was used to harvest 2 rows of each plot. Bags of harvested seed were allowed to dry at ambient temperature to a uniform moisture content before weighing. Weights were converted to yield in bu/acre (60 lb/bu).
Maturity Date...Maturity is considered to be the date when the pods are dry and most of the leaves have dropped. Under most conditions, the stems are also dry.
Plant Height...Plants were measured from the soil to the top extremity, at maturity, and plant height was recorded as the average of the height of plants measured.
Lodging...Lodging was rated and recorded on a scale of:
1 = almost all plants erect
2 = all plants leaning slightly or only a few plants down
3 = all plants leaning moderately or 25 to 50% of plants down
4 = all plants leaning considerably or 50 to 80% of plants down
5 = all plants down.