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  • Author or Editor: Stanley K. Ries x
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Abstract

Sap collected from trees of sugar maple (Acer saccharum Marsh.) in the springs of 1978, 1980, and 1981 was analyzed for 1-triacontanol (TRIA) content. TRIA was present at physiologically active concentrations which varied quadratically with sampling time during each spring season. The maximum TRIA concentration observed was about 11.4 × 10-9M. The highest concentration of TRIA in the sap shifted each year of collection.

Open Access

Abstract

Vegetable and field crops were grown on young residues of several cultivars of sorghum (Sorghum vulgare Pers.) in the greenhouse and field. Seedling growth of field corn (Zea mays L.) in the greenhouse was increased by residues of sorghum shoots, but not by residues of sorghum roots. In contrast the growth of sweet corn in the field was always decreased by residues of ‘Bird-a-Boo’ sorghum roots and whole plants. The growth and yield of snap beans (Phaseolus vulgaris L.) in the field was increased or decreased by sorghum residues depending on the sorghum plant part, quantity, cultivar, and soil environment. Although sorghum residues may stimulate crop growth in some instances, this stimulation was not easily controlled because the optimal range of sorghum residues and soil environment is too narrow and unpredictable.

Open Access

Abstract

Inconsistent yield increases in the United States have prevented recommending triacontanol (TRIA) for commercial application. Based on tests over several years, TRIA is recommended for use on many vegetable and agronomic crops in most provinces in the People's Republic of China. Their formulations were shown either to be less effective or no better than the colloidal dispersion developed by the Procter and Gamble Co. TRIA dispersions passed through 2 standard field sprayers and 3 of 5 experimental small-plot sprayers lost at least 37 % of their activity as measured by the increase in maize (Zea mays L.) seedling growth. Hexane extracts of water passed through sprayers and polyvinyl chloride (PVC) tubing contained more than 5 μg/liter of di-(2-ethyl)hexyl phthalate. This phthalate ester, as well as other phthalates, decreased activity of both the colloidal dispersion and emulsion formulations of TRIA at phthalate concentrations of 5 μg/liter or more. Phthalate esters are common in the environment, including water of developed countries, and are important constituents of the PVC tubing used on most American field and small-plot sprayers. Sprayers equipped with other types of hoses did not inactivate TRIA as measured by the growth of maize seedlings.

Open Access

Abstract

The yield response of crops to triacontanol (TRIA) applied as a colloidal dispersion was tested with 13 crop species in 45 field experiments over a 3-year period. Foliar application of TRIA resulted in treatment effects with 11 of the 13 crops and in 30 of the 45 experiments. The average yield increase was 14% with the optimum TRIA concentration in tests where yield was significantly increased, and was 5% over all 45 experiments. In seven experiments, significant yield decreases averaging 10% were measured with TRIA concentrations that increased crop yield of the same species in other tests. The most effective TRIA concentrations generally were 0.1 to 1.0 μg·liter−1. No particular stage of crop development for treatment was optimal for all crops. Based on the results of these studies, TRIA cannot be recommended for commercial application to crops in Michigan or similar environments. Chemical names used: 1-triacontanol (triacontanol).

Open Access

Abstract

The growth of several vegetable and field crops in the greenhouse was increased by applications of 1-triacontanol to the foliage, soil, or seed. Neither the seed nor soil treatments increased the yield of crops in the field. However, foliar sprays ranging from 5 to 500 mg/ha significantly increased the marketable yield of 7 of 10 crops tested. The average yield increase was based on comparisons of all the different rates and time of 1-triacontanol applications with untreated controls. The response of tomato, carrot and wheat seed treatments with 1-triacontanol was shown to be positively correlated with temperature at time of germination and early growth.

Open Access