Kenaf (Hibiscus cannabinus L.), a promising nonwood fiber crop, produces a high oil content seed that loses viability as exposure to high temperature and humidity increases. Because a large proportion of kenaf seed production in the United States is located in areas with high temperature and humidity, identifying kenaf germplasm with superior seed quality and resistance to weathering and seed coat pathogens should provide beneficial information to both growers and genetic improvement programs. Eight cultivars were evaluated in a darkened seed germinator in the laboratory at 18.5°C for differences in germination, susceptibility to seed coat mold growth, and coefficient of velocity of germination. Laboratory results indicated that percent germination was generally greatest for cultivars Tainung 2, Cubano, Tainung 1, Cuba 108, and Everglades 71 and lowest for 19-117-2. Susceptibility to seed coat mold growth of Cuba 108, Cubano, Tainung 2, and Everglades 71 was consistently less than 19-117-2. Coefficient of velocity of germination or rate of germination was greatest for Tainung 2 and lowest for Everglades 71. In 1991, stand establishment of Everglades 71 and Tainung 2 was greater than 19-117-2. Stand establishment and postemergence damping-off were determined at 42 days after planting. Stands of Everglades 71, Tainung 2, Cuba 108, and Tainung 1 were significantly greater than 19-117-2, 45-9, Cubano, and 78-18RS10 in the 1992 study. Cultivars differed for postemergence damping-off, with Tainung 2, Cuba 108, Tainung 1, and Cubano having less incidence than 78-18RS10. Laboratory and field studies indicated that kenaf cultivars differed in seed quality, stand establishment, and seedling disease susceptibility. Identification and improvement of favorable seed quality traits should result in more uniform stand establishment, seedling vigor, and resistance to the seed-seedling pathogen complex.
