Several elevated concentrations of CO2 were injected into the root atmosphere to determine the influence of CO2 concentration in the soil on the growth of eggplant (Solanum melongena L.). Elevated CO2 levels in the root atmosphere consistently increased stem diameter while a significant increase in plant total dry weight and leaf area only occurred during long day/warm temperature conditions. Under periods of short days and low light levels, 15% CO2 reduced total dry weight and leaf area. Applications of 14CO2 to the root zone demonstrated that 14C eggplant roots absorb CO2 from the soil environment and translocate labeled compounds into the shoot.
Hexazinone was applied as a soil drench to 1-year-old rooted hardwood cuttings of highbush (Vaccinium corymbosum L.) and rabbiteye (V. ashei Reade) blueberries in a series of greenhouse experiments. No differences in susceptibility to hexazinone were detected among 10 highbush and 3 rabbiteye cultivars growing in a fine sand soil. Two highbush and 2 rabbiteye cultivars were assayed for hexazinone tolerance in low, medium, and high organic matter soil which contained 1.3%, 3.5%, and 49.5% organic matter, respectively. Hexazinone at 1 or 2 kg/ha had no inhibitory effect on blueberry growth in the high organic matter soil, inhibited growth slightly on the medium organic matter soil and caused severe injury in the low organic matter soil. At rates of 4 and 8 kg/ha, injury was severe on the medium and low organic matter soils but very slight on the high organic matter soil.
The pest management industry does not have adequate financial incentives to develop the required data to register pest management tools with government authorities on fruit, vegetables, herbs, spices, nursery crops, landscape plants, flowers, turfgrass, and other specialty crops. Growers of these crops, collectively called minor crops, need pest control tools to be able to sustain production. The Interregional Research Project Number Four (IR-4) was established in 1963 by the U.S. Department of Agriculture to assist growers of minor crops by providing a mechanism to allow growers of these crops to have access to safe and effective pest management tools. Working with research, industrial and extension personnel at the state land-grant institutions and researchers at USDA, Agricultural Research Service, IR-4 develops the appropriate data to support registration of insecticides, fungicides, herbicides and plant growth regulators. Many of the uses of plant growth regulators in current use were developed with oversight provided by IR-4. There are many promising new plant growth regulators and/or uses in the commercial development pipeline and it is anticipated that assistance from IR-4 will be needed to support registration of these new materials on minor crops.
Normal embryos and seedling plants were obtained from abortive ovules and seeds of seedless grape cultivars ‘Perlette’, ‘Flame Seedless’ and ‘Sultanina’. Plant development was accompanied by callus formation only in ‘Perlette’. The best medium was Nitsch’s with the addition of 10-5m IAA and 10-6m GA3. Excision and culturing of ‘Flame Seedless’ ovules 49 days after anthesis gave higher germination percentages and more viable plants than excision and culturing at anthesis plus 28. Selfed ‘Perlette’ and ‘Perlette’ × ‘Flame Seedless’ ovules cultured at 52 days gave 11%, and the reciprocal cross over 16% well developed seedlings. The significance of the findings for breeding stenospermocarpic grapes is discussed.