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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.
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’.
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.
Eye-tracking equipment is now affordable and portable, making it a practical instrument for consumer research. Engineered to best analyze gaze on a plane (e.g., a retail shelf), both portable eye-tracking glasses and computer monitor–mounted hardware can play key roles in analyzing merchandise displays to better understand what consumers view. Researchers and practitioners can use that information to improve the sales efficacy of displays. Eye-tracking hardware was nearly exclusively used to investigate the reading process but can now be used for a broader range of study, namely in retail settings. This article presents an approach to using glasses eye tracker (GET) and light eye tracker (LET) eye-tracking hardware for applied consumer research in the field. We outline equipment use, study construction, data extraction as well as benefits and limitations of the technology collected from several pilot studies.
A national survey of the greenhouse and nursery industries was conducted to determine the current status of pest management practices. This study covers the trends in chemical and nonchemical pest control measures and factors that affect adoption of nonchemical control measures. For the 5-year period 1988-93, there appeared to be a decrease in chemical use for disease and insect control and for plant growth regulators. During the same period there was an increase in chemical weed control. The adoption of nonchemical pest control measures was concentrated in the area of insect control. The primary factors limiting use of nonchemical pest control measures were 1) availability of effective materials/biological agents, 2)availability of information, and 3) management complexity. The primary information sources on nonchemical pest control used by growers varied by size of firm and region of the country. For all respondents the primary sources were 1) industry trade journals, 2) other growers in the industry, 3) cooperative extension service, and 4) industry-sponsored seminars.
A national survey of the commercial ornamental industry was conducted to determine the current status of pest control including chemical and nonchemical disease control practices. The fungicides thiophanate methyl, chlorothalonil, mancozeb, and metalaxyl were used in the greatest quantity and by the largest percentage of growers. Metalaxyl was used in greenhouse and field operations by the highest percentage of growers, primarily to control root diseases but many growers reported using metalaxyl to control foliar disease. Overall, more fungicides were used in the field for foliar diseases, whereas almost equal amounts of fungicides were used for foliar and root diseases in the greenhouse.
Growers in the American Association of Nurserymen and the Society of American Florists were queried as to their use of plant growth regulators (PGRs) and nonchemical alternative practices during 1993. Daminozide (B-Nine SP) and chlormequat chloride (Cycocel) accounted for 78% of the total pounds active ingredient and were used by 20% and 17% of the respondents, respectively. In contrast, the rooting compounds indolebutyric acid (Dip `N Grow, Rootone, and Hormoroot) and naphthaleneacetic acid (Dip `N Grow, and Hormodin I, II, and III) were used by 53% and 24% of the respondents, respectively, but combined accounted for less than 3% of total pounds active ingredient. Pruning/pinching was used by the greatest number of respondents (82%) and was the only alternative to PGRs rated as very effective by more than 60% of the respondents. Use of chemical PGRs and nonchemical alternative practices was influenced by region and firm size. In the northeastern United States, growers reported relatively low use of PGRs (frequency and total pounds) and the lowest use of mechanical brushing as an alternative practice. In contrast, mechanical brushing was used most in the western United States. Large firms (more than $2 million in annual sales) reported the greatest use of chemical and nonchemical means of regulating growth.
Members of the American Association of Nurserymen and the Society of American Florists were surveyed as to their use of herbicides and nonchemical alternative weed control practices for 1993. Glyphosate was the top-ranking herbicide among the total of 37 reported, in terms of number of respondents and estimated total amounts of active ingredients applied. It was used by all but two of the respondents that used herbicides in their operations. Oryzalin was the top-ranked preemergent herbicide, and was second only to glyphosate in number of respondents and amount of active ingredient applied. The highest estimated use in amounts of active ingredient applied was in the southeastern (43% of total) and north-central (27% of total) regions, nearly two to three times the estimated use in the northeastern or western regions. However, there were only about 50% more respondents in the southeastern or north-central regions compared to the other regions. About 56% of herbicide active ingredients used were in field sites, 22% in container sites, 19% in perimeter areas, and 3% in green-houses. Large firms (annual sales more than $2,000,000) used the greatest estimated total amount of active ingredients, while small firms (annual sales more than or equal to $500,000) tended to use nonchemical alternatives the most. Nearly all respondents used handweeding or hoeing as part of their weed control program. Mowing was used by 84% of the respondents, 71% used tractor cultivation, and 66% used mulches (includes gravel and black plastic). Alternative methods were rated as somewhat effective to very effective by 65% or more of the respondents who used them.