Monday, November 13, 2006 - 1:45 PM

Poor Field Emergence of Late-Maturing Peanut Cultivars (Arachis hypogaea L.).

Barry Morton, Barry L. Tillman, Daniel W. Gorbet, and Kenneth J. Boote. University of Florida, Newell Hall, Gainesville, FL 32605

Recently released late-maturing cultivars of peanut (DP-1, C-99R, Hull, and MDR-98) when multiplied by commercial seed producers, often exhibit poor field emergence resulting in unacceptable field stands. These late-maturing cultivars are related to PI-203396, a primary source of their superior resistance to leafspot, tomato spotted wilt virus, and white mold. Planting these high yielding cultivars could allow the grower to reduce fungicide applications during the growing season, and reduce the costs of growing peanuts without reducing yields. Because of unpredictable field emergence, commercial seed companies have stopped producing MDR-98 and DP-1. Official germination tests usually show acceptable seed quality. Research shows that reduced field emergence does not occur when the seed peanuts have been grown, harvested, and stored in small batches in research storage facilities. The poor field emergence occurs when seed production is through commercial channels with large volumes being harvested, stored in bulk, and treated with fungicides. The problem may be related to the commercial practice of storing seed peanuts in large piles with no humidity, temperature control, or forced ventilation. Four cultivars from two seed sources stored in five locations were tested for germination using a standard moist towel test in a germinator, and for field emergence planted in sandy soil. Peanuts stored in bulk in a traditional peanut warehouse had reduced field emergence. Peanuts stored in research facilities at mean temperature 12C did not have reduced field emergence. Seed source did not have a significant effect upon field emergence. Cultivars varied in their response to the storage locations. Standard towel germination tests were not reliable indicators of field emergence.