Optimum Plant Population of Roundup Ready Sugarbeet for Highest Yield.

Roundup Ready sugarbeet was developed and approved for commercial use in the United States.  Growers will be able to use two to three applications of glyphosate to effectively control weeds.  However, growers have to pay a technology fee based on planting units.  As such, it will be useful to determine the impact of different plant populations on sugarbeet yield.  The objective of this study was to determine the optimum population of Roundup Ready sugarbeet that would result in the highest recoverable sucrose per acre.  In 2007, trials were conducted at St. Thomas and Prosper, ND.  Plots comprised of six 22-inch wide rows that were 30 feet long.  Plots were planted at 3 inch seed spacing, and thinned at the four to six leaf stage.  At St. Thomas, plant populations after thinning were 100, 125, 150, 175, 200, and 225 plants per 100 ft of row.  At Prosper, planting was done on two dates, May 2 and 24.  The early planting date had populations from 50, in increments of 25, to 175 plants/100 ft of row.  The later planting date had a population from 50, in increments of 25, to 225/100 ft of row.  At St. Thomas, there was no significant different in recoverable sucrose among the different populations.  At Prosper, for both planting dates, except for the 50 plants/100 ft of row, there was no significant difference in recoverable sucrose from populations of 75 to 175 plants/100 ft of row for the early planted beet, nor the 75 to 225 plants/100 ft of row for the later planted beet.  The one year data suggest that a plant population of 75 to 225 plants/ 100 ft of 22-inch wide rows would result in similar yields and earlier planting is critical for higher yields.