( Solenopsis invicta ), an important nuisance pest in the southern United States ( Scherm et al., 2001 ), was exacerbated. Alternative approaches for crown restriction without these drawbacks need to be developed and evaluated. Fig. 1. Schematic illustration of
Fusarium crown and root rot (crown rot) develops on tomato from the fungus Fusarium oxysporum f.sp. radicis-lycopersici (FORL). Genetic resistance to crown rot was previously introduced into the cultivated tomato from the wild species Lycopersicon peruvianum and found to be a single dominant gene, Frl, on the long arm near the centromere of chromosome 9 of the tomato genome. In an effort to identify molecular markers tightly linked to the gene, Ohio 89-1 Fla 7226, Fla 7464, `Mocis', and `Mopèrou', lines homozygous for Frl (resistant), were screened with restriction fragment length polymorphism (RFLP) markers in comparison to Fla 7482B and `Monalbo', lines homozygous for Frl + (susceptible). Frl was determined to be between the RFLP markers CT208 and CD8. These two markers are separated by a genetic map distance of 0.9 cM according to Pillen et al. (1996). In addition, we screened a pool of eight resistant plants against a pool of nine susceptibles from a BC1 population segregating for Frl for amplified fragment length polymorphism (AFLP) markers. Fazio et al. (1998) previously determined that crossover events occurred in these 17 plants between Frl and a rapid amplified polymorphic DNA (RAPD) marker, UBC194. Our research has indicated that UBC194 is also between CT208 and CD8 on the centromeric side of Frl. Of the 62 AFLP primer combinations tested, 34 showed more than 63 strong polymorphisms in linkage to resistant phenotypes.
Agrobacterium vitis is the causal organism of crown gall in grapevine. Infection is particularly severe in areas that experience winter damage to vines. Improving resistance to A. vitis will require a detailed knowledge about this organism. In this study, 18 grapevine isolates of A. vitis were collected from different locations near Lubbock, Texas. Isolates were subjected to a phenotypic characterization using 12 biochemical tests, including production of alkali from L-tartrate, production of 3-ketolactose, utilization of citrate, and others. Previously characterized isolates of A. vitis and A. tumefaciens obtained from the American Type Culture Collection served as positive and negative controls in these assays. Isolates were also evaluated for host range, tumor morphology, and opine utilization, and were compared at the molecular level by restriction fragment length polymorphism analysis of the oncogenic regions of the T-DNA plasmid. Although all isolates were able to metabolize tartrate and grow on Roy–Sasser media, there was much variability based on other tests. Twelve of 18 isolates were able to utilize octopine as a sole carbon source. All isolates tested thus far have been pathogenic on tomato and tests on grapevines are underway.
Salt tolerance in grasses is needed due to increased restrictions on limited fresh water resources and to saltwater intrusion into groundwater. St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is used widely as a lawngrass in states bordering the Gulf of Mexico. We describe the response of four St. Augustinegrass cultivars to solution cultures differentially salinized with synthetic seawater. A sea salt mixture was added to half-strength Hoagland's No. 2 nutrient solution to provide six salinity treatments ranging from 1.1 to 41.5 dS·m-1. Adjustments in leaf water potential, leaf osmotic potential, and leaf turgor potential were measured as salt levels were increased gradually at 2-day intervals over 10 days. Salinity effects on growth of top, crown, and root of each cultivar were measured over 3 months. Turfgrasses differed in their response, but were consistent in adjustment in leaf water potential and in leaf turgor potential as salinity increased. Leaf water potential, leaf osmotic potential, and leaf turgor potential decreased linearly with increased salinity, but a positive turgor of 0.1 MPa was maintained at a salt concentration equal to that of seawater. `Seville', the most salt-tolerant St. Augustinegrass cultivar, exhibited a 50% reduction in top growth at 28.1 dS·m-1, while `Floratam', `Floratine', and `Floralawn' St. Augustinegrasses showed the same reduction in top growth at 22.8 dS·m-1. Differences between cultivars were greatest at salinity levels <10 dS·m-1, where `Seville' was twice as salt-tolerant compared to other cultivars. The grasses did not die, although top growth of all cultivars was severely reduced at a salt level equal to seawater.
Phytophthora capsici Leonian, the causal agent of crown rot, foliar blight, and fruit rot in many vegetable crops ( Hausbeck and Lamour, 2004 ). Currently, there are no commercial C. pepo cultivars immune to P. capsici , but sources of resistance to
effectively reduce ground loss during the machine harvest process similar to earlier experiments with crown restriction ( Rohrbach and Mainland, 1989 ). In addition, longer peduncle and pedicel lengths similar to a sparkleberry fruit cluster should make
the market soil-borne diseases have recently caused major losses in the Australian strawberry industry. Fusarium oxysporum is associated with a group of pathogens causing crown and root diseases of strawberry. These include: Colletotrichum species
, or utility patent. Roots from the 87 cultivars with no associated IPR restrictions were selected and advanced for breeding during the winter of 2013–14 ( Table 1 ). Hybrids that were available to use in breeding were included in the composite
leakiness in ‘Chester’ and ‘Triple Crown’, but did not cause weight loss or color change of any variety. ‘Chester’, ‘Triple Crown’, ‘Osage’, ‘Prime-Ark® Traveler’, and ‘Von’ benefited from immediate storage. Long-term storage reduced postharvest quality of
ribbed with dark-green to green-and-orange-striped skin and is slightly smaller than most kabochas. ‘Crown’ is crown-shaped, with smooth gray to pink skin, and is larger than most kabochas. North American consumers are not familiar with either of these