Search Results
You are looking at 1 - 5 of 5 items for :
- Author or Editor: R. K. Jones x
- HortScience x
Abstract
Selected gibberellin A3 (GA3) rates and application dates on yield and harvest efficiency of the savoy spinach (Spinacea oleracea) cultivar ‘Iron Duke’ were evaluated. The most favorable yield response was achieved under fall conditions with 15-20 g GA3/ha applied 7–14 days prior to the anticipated harvest date. When cool temperatures (5° to 12°C) prevailed during the treatment and posttreatment periods, increased GA3 rates and prolonged response times were necessary. Gibberellin A3 did not induce bolting when applied as early as 1 Nov. but applications later than 15 Feb. enhanced the rate of seed stalk development.
Twelve shrub rose cultivars were evaluated for pest resistance in the southern Blue Ridge mountains under high humidity and rainfall (1.34 inches per week average during the 1994 and 1995 growing seasons). `Albo plena', `Blanc Double de Coubert', `Fru Dagmar Hastrup', `Roseraie de l'Hay', R. rugosa `Alba', `Sarah van Fleet', and `Topaz Jewel' were highly resistant to black spot and Cercospora sp. leaf spot. `Alba Meidiland', `Linda Campbell', `Pink Meidiland', and `Scarlet Meidiland' were susceptible, while `Bonica' displayed intermediate resistance to both diseases. `Sarah van Fleet' foliage and the flowers of `Albo plena', `Blanc Double de Coubert', and R. rugosa `Alba' were damaged by Japanese beetle feeding. No other cultivars were damaged by Japanese beetles.
Flow cytometry (FC) has proven to be an efficient and reliable method to estimate nuclear DNA content (genome size) in quantifiable units useful for genetic and molecular biology studies. This method also makes possible determination of the variation in nuclear DNA content between related taxa, which gives insights into the process of speciation. In this study, DNA content was determined in nuclei isolated from leaves of 21 Dendrobium species representing each of the major taxonomic groups used in the Univ. of Hawaii breeding program. Nuclei were mechanically isolated, stained with the nucleic acid-specific fluorochrom propidium iodide, and DNA content determined using a Coulter Epics 753 laser flow cytometer. Chicken erythrocyte nuclei (2C = 2.33 pg DNA) were used as an internal standard for direct comparative measurement. The mean diploid genome (2C) values for Dendrobium species ranged from 3.36 to 5.06 pg. Genome sizes were evaluated for possible use as discrete characters for taxonomic group assignment and compared to previous data on breeding compatibility and evolutionary relationship between species.
Fifteen shortday onion cultivars grown at two production locations (GB and ST) in the Lower Rio Grande Valley, Texas were evaluated for pungency levels using gas chromatography (GC) and pyruvic acid tests.
Significant differences (P=0.05) were observed between cultivars in the pyruvic acid and GC tests within each location. Pyruvic acid content ranged from 3.0 to 5.1 μmol·g-1 fresh wt. The amount of total sulfur volatiles measured by the GC method ranged from 28 × 103 to 58 × 103EU. The correlation coefficients between GC and pyruvic acid were 0.10*** and 0.18*** at the GB and ST location, respectively.
When the two locations were combined, no significant differences (P=0.05) were observed between cultivars or locations using the GC test. However, the pyruvic acid test showed significant differences between locations. This result indicated that each cultivar had a different response in pungency as influenced by production location or environment.
Abstract
‘Royal Red Cherry’ and ‘Short Red Cherry’ are indeterminate, fruitful and multiple disease resistant tomato cultivars. ‘Royal Red Cherry’ is similar to ‘Large Red Cherry’ and ‘Jumbo Cherry’ in fruit size and quality, but is a more prolific yielder. ‘Short Red Cherry’ has a more compact vine type that is based on the brachytic (br) gene and it is most desirable for the patio, container gardener. ‘Short Red Cherry’ is generally earlier in production pattern than ‘Royal Red Cherry’.