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- Author or Editor: Ellen T. Paparozzi x
`Dark Yellow Fuji Mefo' chrysanthemums (Dendranthema grandiflora Tzvelev.) were grown hydroponically with either 64, 127, or 254 mg·L-1 N and either 0, 1, 2, 4, 8, 16, 32, or 64 mg·L-1 S in a randomized complete block. Time to flower was measured and symptoms of S deficiency were observed on root, stem, and leaf systems. New leaves and inflorescences were analyzed for S, and lower leaves were analyzed for N concentration. There were four sampling dates and two experiments. Flower diameter was measured when flowers were present, while stem length was measured every sampling date. Nitrogen application could be reduced by half to 127 mg·L-1 as long as some S, 4 mg·L-1 in the fall and 8 mg·L-1 in the spring, was applied. Sulfur deficiency symptoms observed included branchless roots, which aged earlier, overall yellowing of new leaves, and reddening on the leaf abaxial starting from older leaves and moving acropetally. Plants receiving no S had smaller leaves, shorter stems, delayed inflorescence initiation, and restricted inflorescence development. Without S, plants did not produce flowers suitable for commercial sale.
We examined all articles in volume 139 and the first issue of volume 140 of the Journal of the American Society for Horticultural Science (JASHS) for statistical problems. Slightly fewer than half appeared to have problems. This is consistent with what has been found for other biological journals. Problems ranged from inappropriate analyses and statistical procedures to insufficient (or complete lack of) information on how the analyses were performed. A common problem arose from taking many measurements from the same plant, which leads to correlated test results, ignored when declaring significance at P = 0.05 for each test. In this case, experiment-wise error control is lacking. We believe that many of these problems could and should have been caught in the writing or review process; i.e., identifying them did not require an extensive statistics background. This suggests that authors and reviewers have not absorbed nor kept current with many of the statistical basics needed for understanding their own data, for conducting proper statistical analyses, and for communicating their results. For a variety of reasons, graduate training in statistics for horticulture majors appears inadequate; we suggest that researchers in this field actively seek out opportunities to improve and update their statistical knowledge throughout their careers and engage a statistician as a collaborator early when unfamiliar methods are needed to design or analyze a research study. In addition, the ASHS, which publishes three journals, should assist authors, reviewers, and editors by recognizing and supporting the need for continuing education in quantitative literacy.
Research previously conducted on leaf lettuce has shown that altering the amount of N and S applied had an effect on plant growth, color, N content and S content. The amount of N and S applied to the plant also affected consumer acceptance of leaf lettuce.
The leaf lettuce cultivar `Grand Rapids' was grown hydroponically at 8 different treatment combinations consisting of four N levels (30, 60, 120, and 240 ppm) and three S levels (7.5, 15, and 120 ppm). Ascorbic acid content was determined immediately after harvest using the 2,6-dichloroindophenol method. Color was measured with a chromometer.
Results indicate that differences in ascorbic acid content could be detected between the various treatments. Plants which were darker green in color contained more ascorbic acid than plants yellow-green in color. Nitrogen applied had a significant effect on the ascorbic acid content while sulfur applied had no effect on ascorbic acid content of fresh leaf lettuce.
`Dark Red Annette Hegg' poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch) were grown in a 1 peat : 1 perlite : 1 vermiculite medium using a pinched production schedule with varying N and S fertilizer application rates. Fifty-six treatments consisting of eight N levels (100 to 275 mg·L−1 in 25-mg·L−1 increments) and seven S levels (0 to 75 mg·L−1 in 12.5-mg·L−1 increments) were supplied. Other required nutrients were supplied at commercial recommendations for all treatments. Foliage of each plant was evaluated quantitatively by chromometer readings every 3 weeks. Marketability was determined by sensory evaluations from commercial producers, retailers, and consumers. Results indicated distinct color differences (hue, chroma, value) between S levels of 0 and 12.5 mg·L−1 and a slight difference between S at 12.5 and 25 mg·L−1. The foliage of plants receiving 0 S was lighter, more vivid, and more yellow-green in color. As N levels increased, there was a linear response; foliage became more green, darker, and more dull. Commerical and consumer evaluators rated plants that received S at 0 or 12.5 mg·L−1 at all N levels and plants receiving N at 100 mg L−1 as unmarketable. This research indicates that `Annette Hegg' poinsettia requires S at a minimum of 25 mg·L−1 and N at a minimum of 125 mg·L−1 for commercial acceptance, and commercial N application rates may be greatly reduced when adequate S is supplied.
Processed corn (Zea mays L.) stover (PCS), defined as finely ground stover with or without additions, could be a potential alternative to peat in greenhouse mixes. However, this option has not yet been examined. We performed two split-plot experiments (1 and 2) with tomatoes (Solanum lycopersicum L.) and marigolds (Tagetes patula L.) as main plots. Expt. 1 involved five stover rates (0%, 25%, 50%, 75%, and 100% by volume) mixed with peat as subplots. Expt. 2 involved 0% stover mixed with peat, 25% distillers grain, and 50% quick compost (mechanically processed to accelerate compost process) stover with and without CaO, and 75% quick compost stover without CaO, as subplots. We measured growth parameters (height, dry weight, and flower number) and properties of the mixes. During Expt. 1, across both species, the addition of stover at rates >50% reduced relative greenness by 40%, vegetative biomass yield by 74%, and reproductive biomass yield by 73% compared to mixes with 0% and 25% stover. As the stover rate increased, available water content in the mixes decreased (r = −0.34; P < 0.001). Mixes with 0% and 25% stover had 34% more available water than mixes with 100% stover, which probably reduced plant growth in the 100% stover treatment. As the stover rate increased, plant tissue N and P concentrations decreased. Mixes with 0% stover generally had greater N and P concentrations than mixes with stover. During Expt. 2, for marigolds, the addition of 50% quick compost stover+CaO and 75% quick compost stover-CaO reduced relative greenness by 19% and vegetative biomass by 66% compared to mixes with 25% distillers grain or 0% stover. For tomatoes, the addition of 50% quick compost stover+CaO and 75% quick compost stover-CaO reduced biomass yield by 64%, which may be due to the higher pH and electrical conductivity (EC) of both treatments. Plant tissue N and P concentrations were greater in the mix with 25% distillers grain compared to most treatments, but N and P concentrations in the other mixes varied. Overall, the 25% distillers grain (3 peat: 1 distiller grain: 4 perlite) and 25% stover (3 peat: 1 stover: 4 perlite) treatments showed the most promise as additives in a peat-based mix.
We examined all articles in volume 139 and the first issue of volume 140 of the Journal of the American Society for Horticultural Science (JASHS) for statistical problems. Slightly fewer than half appeared to have problems. This is consistent with what has been found for other biological journals. Problems ranged from inappropriate analyses and statistical procedures to insufficient (or complete lack of) information on how the analyses were performed. A common problem arose from taking many measurements from the same plant, which leads to correlated test results, ignored when declaring significance at P = 0.05 for each test. In this case, experiment-wise error control is lacking. We believe that many of these problems could and should have been caught in the writing or review process; i.e., identifying them did not require an extensive statistics background. This suggests that authors and reviewers have not absorbed nor kept current with many of the statistical basics needed for understanding their own data, for conducting proper statistical analyses, and for communicating their results. For a variety of reasons, graduate training in statistics for horticulture majors appears inadequate; we suggest that researchers in this field actively seek out opportunities to improve and update their statistical knowledge throughout their careers and engage a statistician as a collaborator early when unfamiliar methods are needed to design or analyze a research study. In addition, the ASHS, which publishes three journals, should assist authors, reviewers, and editors by recognizing and supporting the need for continuing education in quantitative literacy.
We examined all articles in volume 139 and the first issue of volume 140 of the Journal of the American Society for Horticultural Science (JASHS) for statistical problems. Slightly fewer than half appeared to have problems. This is consistent with what has been found for other biological journals. Problems ranged from inappropriate analyses and statistical procedures to insufficient (or complete lack of) information on how the analyses were performed. A common problem arose from taking many measurements from the same plant, which leads to correlated test results, ignored when declaring significance at P = 0.05 for each test. In this case, experiment-wise error control is lacking. We believe that many of these problems could and should have been caught in the writing or review process; i.e., identifying them did not require an extensive statistics background. This suggests that authors and reviewers have not absorbed nor kept current with many of the statistical basics needed for understanding their own data, for conducting proper statistical analyses, and for communicating their results. For a variety of reasons, graduate training in statistics for horticulture majors appears inadequate; we suggest that researchers in this field actively seek out opportunities to improve and update their statistical knowledge throughout their careers and engage a statistician as a collaborator early when unfamiliar methods are needed to design or analyze a research study. In addition, the ASHS, which publishes three journals, should assist authors, reviewers, and editors by recognizing and supporting the need for continuing education in quantitative literacy.
Seedcoat color is an important trait, as it affects marketing and consumer acceptance of pinto beans (Phaseolus vulgaris L.). Pinto breeding line NE 94-4 showed seedcoat yellowing in on-farm field trials in Nebraska in 1996 and 1997. Hail, sprinkler irrigation, and fall rainfall appeared to be involved in increasing seedcoat yellowing, based on analysis of field and weather data of on-farm trial sites. The objective of this study was to determine the effect of moisture on seedcoat yellowing of pinto line NE 94-4 (susceptible) and pinto `UI-114' (highly resistant). Two greenhouse experiments were conducted involving misting of bean plants near maturity and injecting water into maturing bean pods. Another experiment evaluated the response of seeds of these two bean entries to moisture by placing them on moist filter paper in petri dishes in the laboratory. Results showed that both genotype and moisture content are involved in seedcoat yellowing. This simple, cheap, and effective filter paper test was then used to evaluate seedcoat yellowing of nine pinto genotypes in response to moisture. Pinto NE 94-4 and `Kodiak' showed the greatest change, while `Bill Z' showed the least change, in seedcoat color.
Case studies promote the development of problem-solving skills, but few have been created for horticulture and related curricula. This web-based decision case presents the challenge of determining the cause of symptoms of foliar chlorosis in a crop of cut Dicentra spectabilis while forcing it for Valentine's Day sales. It provides a tool to promote the development of diagnostic skills for production dilemmas, including nutritional disorders, disease and insect problems, and evaluation of the appropriateness of cultural practices. Cut Dicentra is a minor crop and standard production practices are not well established. Therefore, solving this case requires that students research production protocol as well as nutritional and pest problems to develop a solution. In this case study, which is supported by an image-rich web-based version at www.hightunnels.org/cutflowercasestudy.htm, a grower at Flint's Flower Farm must determine the cause of foliar chlorosis that is slowly appearing on about half of the plants of her cut Dicentra crop. The condition could be related to a number of possible problems including a nutritional disorder, insect attack, disease infection, or production practices. Some resources are provided to aid students in gathering background information. Data accumulated by the grower is presented to allow students to logically eliminate unlikely solutions and predict (a) probable cause(s). The solution, which is rather unique to this crop, is provided. This case study is intended for use in upper-level undergraduate courses of floriculture production, nutrient management, plant pathology, and entomology.
Woody floral stems are an emerging specialty crop within the floral industry, and stem color is a key to marketability. This study was conducted to assess stem color change over time in order to determine the optimum window for stem harvest. Plants of `Scarlet curls', `Flame' willow, `Bailey', `Cardinal' and `Yellow twig' dogwood were planted in a randomized complete block design in rows parallel to a windbreak.. Each experimental unit consisted of a group of five plants, each of the same cultivar. Plants were initially tagged at a set height and stem diameter and measured for color. Each stem was also tagged with one of three colored tapes, according to initial color: green for green colored stems, red for stems already showing color change, and pink for intermediate colored stems. Color was assessed initially and on a weekly basis for 10 weeks, starting at the end of September, using the Royal Horticultural Society color chart. Data were analyzed using a repeated measures procedure. `Scarlet curls' and `Flame' stems, already displaying color, attained the darkest color value for their cultivar at an early stage and were at the point of harvest in early November, while stems that were initially green never attained a similar dark color value. `Yellow twig' dogwood stems already displaying color and those beginning to color attained the darkest color value in late November. `Cardinal' stems attained a darker color value more quickly than other dogwood stems. In most cases, stems of `Cardinal' dogwood could be harvested from early October until early December, while early November was the optimum time to harvest `Bailey' dogwood stems. Woody florals planted closest to the windbreak were more variable in color development and, in some cases, appeared to be more vigorous.