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- Author or Editor: H. H. Marshall x
Abstract
The improvement of winter hardiness of tender tetraploid hybrid tea, grandiflora and floribunda roses has been difficult because of interspecific crossing barriers between these and hardy northern species.
Abstract
New sources of peonin in Rosa have been found in R. acicularis Lindl., R. arkansana Porter and R. × dulcissima (Lunell) W. H. Lewis. Peonin has been transferred from the native tetraploid, R. arkansana, to fertile tetraploid hybrids with Floribunda and Hybrid Tea roses. Cyanin, peonin and pelargonin combined have been found in 10 seedlings derived from these crosses, a combination not previously reported in Rosa.
A separate pair of blue fluorescing spots bore a positive relationship to each of cyanin, peonin and pelargonin. A negative relationship was observed between yellow fluorescent spots, probably flavonoids, and anthocyanins.
Abstract
Many rose breeders have sought the often elusive combination of plant quality and hardiness, but have had to compromise by accepting undesirable plant quality such as single flowers or large plant size to obtain hardy cultivars. The breeding program at the Morden Research Station was designed to develop hardy, attractive roses for the Canadian prairie conditions. Plants of hybrid tea and floribunda roses were used as sources of desirable foliage and flower traits. The main source of hardiness was a native prairie rose, Rosa arkansana Porter. Cultivars developed from this program are known collectively as the Parkland Rose Series (1). In the past, seedlings in the breeding program were generally large bushes, 1.5-2.0 m in height; however, in 1971 a few smaller plants 40–50 cm high were observed. ‘Morden Amorette’ and ‘Morden Cardinette’ roses were selected from this latter group and introduced by the Morden Research Station in 1977 and 1980, respectively.
Nationally, the number of operating farmers' markets has increased 111% from 1755 markets in 1994 to 3706 in 2004. Indiana's farmers' markets have increased at double the rate in the same timeframe. An Internet and mail census was sent to market managers to assess operational procedures and factors that influence customer and vendor participation in the market. A two-stage least squares model was estimated for the vendor and customer model. Paying fees and the number of customers present were the two variables that had a significant, positive influence on vendor participation. The presence of WIC, number of products available, the absence or presence of live music, absence or presence of cooking demonstrations, and number of vendors were significant for the customer model. The absence or presence of concession stands and picnic areas was significant at the 0.10 level in the customer model.
Abstract
Temperature requirements for rest development were determined and used in developing an empirical model for predicting rest development in terminal vegetative buds of Cornus sericea L. Vegetatively mature plants were exposed to 5° to 20°C under a 12-hr photoperiod (SD) in growth chambers, and depth of rest was measured by days to terminal bud break at 20°/15° (day/night) under a 16-hour photoperiod (LD). Rest development proceeded only after vegetative maturity was attained. Time from vegetative maturity to maximum rest decreased with decreasing temperature. Rate of rest development at all temperatures varied and was dependent on growth stage. The annual growth cycle and rest development were described and quantified by a degree growth stage (°GS) model. Using temperature and accumulating °GS, the model predicted maximum rest within 2 days in both years.
Abstract
Tree trunks painted on the sunlit side with white exterior latex paint were found to be 30 C cooler than nonpainted trunks during midwinter in midlatitudes. The dependency of the cambium temp amelioration on wind speed and trunk diam is indicated through an argument based on convective transfer theory. The argument suggests that for trunks larger than 10 cm diam or for wind speeds less than 30 cm/sec around the trunk or both, the amelioration due to white paint may be greater than 30 C.
Fresh and processed tomato (Lycopersicon esculentum) consumption has increased 40% in the United States over the last two decades. Through better breeding, fresh tomatoes now are marketed in different forms, sizes, colors, and flavors. However, little published information exists concerning consumer demand, preference, and demographic characteristics related to fresh tomato consumption. Taking advantage of a high percentage of Internet use in the U.S., two web-based surveys were released to approximately 6000 e-mail addresses reaching people in every region of the U.S. The surveys contained a total of 61 questions, including 50 digital images of five types of tomatoes (cherry, grape, cluster, plum, and regular slicing) with combinations of three additional factors (price, lycopene content, and production style) and demographic information. Among 389 respondents, 76% preferred and purchased slicing tomatoes in the 4 weeks prior to the survey. These were followed by grape/mini-pear (42%), plum (36%), cluster (27%), cherry (25%), and yellow slicing tomatoes (4.4%). Overall, production method (organic vs. conventional) had low relative importance in comparison to price and tomato type. However, younger participants (<age 38 years) placed more importance on production method. Participants between ages 39 and 57 years were the most price-sensitive, and female were less sensitive than males. Younger participants (<age 38 years) were less price-sensitive and placed more importance on the other attributes (production method, lycopene content, and tomato type).
Sunflower ‘Sunfinity’ (Helianthus hybrida) can be produced as a potted plant if apical dominance is removed with a manual pinch to control plant height and promote branching and flower number. Chemical pinching agents such as dikegulac sodium could prove to be valuable tools to reduce the labor and costs associated with manual pinching. Our objective was to determine the time of seedling growth and concentration of dikegulac sodium foliar spray application that would result in morphology similar to manually pinched plants. Dikegulac sodium was applied to sunflower ‘Sunfinity’ seedlings at one of four concentrations increasing from 200 to 500 mg⋅L−1 at the time of growth when the first, second, or third node (N1, N2, or N3) was the apical node and axillary stems at those nodes were undeveloped. Applications of 400 mg⋅L−1 at N3 and 500 mg·L−1 at N2 removed apical dominance because of total senescence of the apical meristem and produced a well-branched plant similar to that subjected to manual pinching. Apical dominance was temporarily inhibited without senescence of the apical meristem when 400 mg⋅L−1 was applied at N2 and when 500 mg⋅L−1 was applied at N3, which, nevertheless, resulted in branching that formed a well-rounded canopy.
Abstract
A stem flow gauge designed for herbaceous plants was adapted for measuring the absolute mass flow rate of sap in large stems and trunks of woody plants. The method uses a steady-state heat balance method in which a constant, known amount of heat is supplied to a stem segment. The axial and radial conductive heat fluxes away from the heated segment are measured, as well as the rise in sap temperature. The device can be operated by commonly available dataloggers and does not require calibration. In a greenhouse experiment with a small tree, the sap mass flow rate, as measured by the the gauge, agreed with the measured transpiration rate within 4% when both were integrated over 24-hr periods or longer. Short term comparisons (≤4hr) were less accurate, due to the changes in water content of the tree above the gauge, which cause a lag between transpiration rate and sap flow rate. The dynamic response of the tree and gauge system to sudden changes in sap flow was ≈20 min under midday conditions. Other than the insertion of temperature-sensing thermocouples 2 mm into the trunk, the gauge components are non-invasive and do not disturb the tree physically or physiologically to a significant extent.
High summer temperatures may reduce plant stands of direct-seeded fall broccoli (Brassica oleracea var. italica Plenck). The influence of constant and diurnally alternating temperatures in the range of 5 to 42C on germination and emergence of `Packman' broccoli was evaluated. Germination was defined as protrusion of the radicle from the seedcoat, and emergence as 10 mm elongation of the radicle. The range of constant temperatures from 10 to 30C for 14 days was satisfactory for 90% germination and 75% emergence. However, alternating temperatures extended the acceptable emergence range to 5/17 through 20/32C. Since soil temperatures in warm climates often exceed 20/32C during the summer, high-temperature inhibition of seed germination and seedling emergence is a potentially important factor limiting direct-seeded broccoli stands.