embryo culture were used to produce inter specific walnut hybrid plants between juglans nigra l. and j. regia l. developed ovaries were collected from j. rejia female flowers which were pollinated with j. nigra pollen grain by high dusting on a mature tree. in order to isolate embryos, exocarps were aseptically removed. isolated embryos from ovules at different developmental stages were transfe...

Thousand cankers disease (TCD) is a newly recognized disease of various species of walnut (Juglans). Black walnut (Juglans nigra) is particularly susceptible to TCD and during the past decade it has devastated plantings of black walnut in most western states. In July 2010 thousand cankers disease was found over an extensive area around Knoxville, Tennessee, the first finding of TCD within the n...

Several North American walnut species (Juglans spp.) are threatened by thousand cankers disease which is caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and its associated fungal plant pathogen, Geosmithia morbida M. Kolarík, E. Freeland, C. Utley and N. Tisserat sp. nov. Spread of this disease may occur via movement of infested black walnut (Juglans nigra L.) wood. This stu...

The expressed sequence tag (EST) database represents a potentially valuable resource for the development of simple sequence repeat (SSR) markers for use in evolutionary studies. EST-SSRs reveal polymorphisms not only within the source taxon, but in related taxa as well. In this paper, we describe a case study in which the publicly available walnut (Juglans regia) EST database was used to develo...

The ascomycete Geosmithia morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease of Juglans (walnut) and Pterocarya (wingnut). The disease was first reported in the western United States (USA) on several Juglans species, but has been found more recently in the eastern USA in the native range of the highly susceptible Juglans nigra. We performed a...

Thousand Cankers Disease (TCD) of Juglans and Pterocarya (Juglandaceae) involves a fungal pathogen, Geosmithia morbida, and a primary insect vector, Pityophthorus juglandis. TCD was described originally from dying Juglans nigra trees in the western United States (USA), but it was reported subsequently from the eastern USA and northern Italy. The disease is often difficult to diagnose due to the...