Stand Establishment of Sugar Beet Seedlings in Pathogen-Infested Soils as Influenced by Cultivar and Seed-Priming Technique. Charles M. Rush, Professor, Department of Plant Pathology, The Texas A&M University System, Texas Agricultural Experiment Station, P.O. Drawer 10, Bushland 79012. . Plant Dis. 76:800-805. Accepted for publication 7 March 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0800.

A greenhouse study was conducted to determine whether selected sugar beet (Beta vulgaris) cultivars responded differently to various seed-priming techniques. Priming techniques included osmopriming with –1.5 MPa NaCl or –1.2 MPa polyethylene glycol (PEG 8000) and solid matrix priming with water and a hydrous silicate clay mineral as the solid substrate. Washed and nontreated seed were used as controls. Treated seed of cultivars Ach146, Ach177, HH42, and Tx9 was planted in a silt loam–peat soil mix artificially infested with Aphanomyces cochlioides or Pythium ultimum, or in noninfested soil. Seedling emergence and damping-off were recorded daily. Although varying in degree, all cultivars responded similarly to the different seed treatments. There was typically no seed treatment × cultivar interaction with any of the recorded variables at any time. All priming treatments increased the rate and uniformity of seedling emergence and also reduced the incidence of preemergence damping-off in soils infested with P. ultimum. There was a small but significant positive correlation between T₅₀ (the weighted mean time for emergence of all seedlings) and preemergence damping-off (R² = .23, P ? 0.05). As T₅₀ increased (slower emergence), preemergence damping-off increased. P. ultimum caused both preemergence and postemergence damping-off; however, A. cochlioides caused only postemergence damping-off. Although priming treatments reduced preemergence damping-off, no treatment significantly reduced postemergence damping-off.