Mark P. Harrison1, Normie Buehring1, Steve P. Nichols2, and R. R. Dobbs3. (1) Mississippi State University, P.O. Box 456, 5421 Highway 145S, Verona, MS 38879, (2) Delta Research and Extension Center, P.O. Box 197, Stoneville, MS 38776, (3) North Mississippi Research and Extension Center, P.O. Box 1690, Verona, MS 38879
A three year (2003-2005) seeding rate study at Verona and Stoneville, MS, evaluated three transgenic varieties, ST 4892BR, ST 5599BR, and DP 555BG/RR for lint yield, fiber quality and gross returns. Vacuum planters were calibrated to deliver seeding rates of one, two, three, four, and five seed/ft of row which resulted in plant populations of 12,000, 23,000, 32,000, 43,000 and 52,000 plants/A, respectively. The results showed no differences between locations. The emerged plant populations were obtained under optimum seedling emergence conditions with no heavy rain or soil crusting during the emergence period. The one seed/ft showed delayed maturity. Percent lint turnout only showed differences among varieties. Seeding rates had minimal effect on fiber quality with no differences in net loan price. The one and two seed/ft showed lower lint yield and gross returns than three, four, or five seed/ft. The three, four and five seed/ft showed no yield or gross return differences. Before reducing seeding rates from the recommended four to five seed to three seed/ft of row one should consider field conditions at planting, the potential for soil crusting during the seedling emergence, seed quality, seed cold germination and vigor test results.