| Late-maturing peanut cultivars DP-1, C-99R, Hull, and Florida MDR-98 (Arachis hypogaea L.) have superior resistance to leafspot (Cercosporidium personatum, Berk & Curt.), white mold (Sclerotium rolfsii, Sacc.), and tomato spotted wilt virus. The improved resistances are primarily derived from PI 203396. The cultivars are high yielding. They provide the grower the opportunity to reduce fungicide applications and variable costs without reducing yields. Because of poor field emergence, commercial seed companies have stopped producing Florida MDR-98, DP-1, and Hull. Official towel germination tests usually show acceptable seed quality. Reduced field emergence seldom occurs 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 bins, and treated with fungicides. The problem may be related to the commercial practice of storing seed peanuts in large piles with inadequate ventilation.; Four cultivars from two different field origins were stored in four environments and then tested for field emergence. Field origin did not affect field emergence, but storage environment did. Peanuts stored in bulk in a traditional peanut warehouse at elevated temperatures and relative humidity had reduced field emergence. There was a genotype by storage environment interaction. Field emergence was maintained when seed was stored at <16°C and <70% relative humidity. Standard towel germination tests were not reliable indicators of field emergence. Electrolyte conductivity tests and seed vigor tests were highly correlated with field emergence. The increased electrolyte conductivity and decreased rate of growth of the hypocotyl-radicle indicated that cellular membranes were damaged during storage at elevated temperatures and relative humidity. The literature suggests that peroxidation of lipids occurred resulting in the production of free radicals and autoxidation. The antioxidant capacity of seed varied by cultivar and year of production.; Field emergence could be improved by reducing temperature and relative humidity in the storage environment. Since standard towel germination tests were not reliable indicators of field emergence for these late-maturing cultivars, an alternative method of evaluating peanut seed quality should be adopted. |
