Search Results
Abstract
Roots of flooded highbush blueberry (Vaccinium corymbosum L.) plants examined by light and scanning electron microscopy exhibited enlarged epidermal cells, compressed cortical cells, and disrupted vascular tissue. The stems of flooded plants showed disrupted epidermal tissue, condensed outer cortical cells, and large aerenchyma-like mid-cortical tissue. Leaves from flooded plants showed an increase in intercellular spaces in the spongy mesophyll and a disrupted palisade layer. There were no apparent differences in inflorescence bud anatomy, although inflorescences were small and delayed in development.
Abstract
Two-year-old container-grown highbush blueberry plants (Vaccinium corymbosum L. ‘Bluecrop’) were flooded outdoors, beginning in December, April, and August, to determine the seasonal effects of root-zone flooding on reproductive growth. Flooded plants had 61-77% fewer flower buds and 55-66% fewer flowers per bud, compared to nonflooded plants. Anthesis was delayed about 6 days in flooded plants. Fruit set was decreased 45% and fruit abscision increased with flooding. Fruit weight, fruit size, and percentage of soluble solids from flooded plants were reduced significantly.
Abstract
Watered split-root portions of 2-year-old plants of ‘Bluecrop’ blueberry (Vaccinium corymbosum L.) exhibited significantly greater shoot dry weight, shoot thickness, shoot length, mean number of shoots, and leaf dry weight than nonwatered portions. Watered portions blossomed, produced fruit, and set new flower buds while existing flower buds died and no new flower buds formed on the nonwatered portions.
Abstract
Flooded, 2-year-old highbush blueberry plants (Vaccinium corymbosum L. ‘Bluecrop’) survived 30 months of continuous flooding, but vegetative growth was suppressed after ≈4 months. Plants continuously flooded for 4 months and subsequently placed in the field recovered partially. The greatest number of plants died when flooding began in April and the least number when it was begun in December.
Abstract
Annual growth of white unsuberized roots from mature ‘Earliblue’, ‘Bluecrop’, and ‘Lateblue’ blueberry (Vaccinium corymbosum L.) plants relative to soil temperatures, shoot growth, and stage of development was studied for 3 years. The growth of roots continued throughout the year, but was much reduced at soil temperatures below 8°C. Two peaks in the growth of roots occurred, the first in early June and the 2nd, higher peak in September. Both peaks in root growth occurred with soil temperatures of 14° to 18°. The growth rate declined at soil temperatures outside this range. Growth of roots was concomitant with shoot growth.
Four fungicides were evaluated for their effects on in vitro pollen germination of muskmelon (Cucumis melo L.) cultivars TAM-Uvalde and Magnum 45. Cupric hydroxide, mancozeb, and chlorothalonil reduced the percentage of pollen that germinated and rate and length of germ-tube elongation, regardless of cultivar. Benomyl had very little overall effect on pollen germination or germ-tube elongation. With the effective pollination period of ≈ 10 to 14 days in commercial production, each day is critical for maximum crown set. Based on our results. some fungicides may be contributing to reduced fruit set in muskmelon.
Three cold-climate strawberry production systems, conventional matted row, advanced matted row, and cold-climate annual hill plasticulture, were compared for consumer preference in a pick-your-own (PYO) setting. Replicated 6 × 15 m plots were established in 2002 in Maryland and cropped in 2003 and 2004. To simulate PYO marketing, volunteers were recruited to harvest 3.6-m plots in each of the three production systems and to complete a five-part questionnaire. The questionnaire collected demographic information and allowed volunteers to compare the three systems both prior to and after their harvesting experience. Harvests were carried out twice weekly, with 75 participants in 2003 and 45 participants in 2004. The 2003 season was cool and wet, with frequent rainfall and a high incidence of fruit rot. Spring 2004 was unseasonably hot, resulting in an unusually short harvest season. Consumer preference differed between years and among harvests within a season. The annual hill system was favored early in the 2003 season, with preference shifting to the other systems as the season progressed. The advanced matted row was favored early in the 2004 season. Many of the participants' comments, both positive and negative, were directed at the plastic mulch and raised beds. In several cases, participants indicated that their preferences after picking from each system did not match their initial impressions. Implications of this research to the social components of sustainability will be discussed.
Abstract
Crack-susceptible and crack-resistant tomato (Lycopersicon esculentum L. Mill.) cultivars were grown in soil beds and in bags filled with a peat-vermiculite mix. Plants in soil were drip-irrigated 1 or 4 times daily, or hand-watered every day or as needed based on soil moisture tension. Plants in bags received only drip-irrigation treatments. Genotype had the greatest effect on fruit cracking, with 3.8% by weight cracked fruit in the crack-resistant compared to 35.3% in the crack-susceptible cultivar. Growing plants in bags reduced the weight and the percentage of cracked fruit per plant, but, in both cultivars, total and No. 1 fruit weights were greatest from the soil treatments with drip-irrigation. Irrigation frequency and method did not affect fruit weight except in the crack-resistant cultivar grown in bags where increasing irrigation frequency increased weights. Cracking was decreased by 22% in tomatoes irrigated manually every day, compared to those irrigated only when needed. In the soil treatment, raising the irrigation frequency significantly decreased cracking in the susceptible, but not in the resistant cultivar. In the soilless treatment, frequent irrigation increased cracking in both cultivars.
In consumer-harvested marketing, crop management practices and production systems directly affect the experience of the customer. An experiment was designed to compare overall consumer preference and fruit quality characteristics among three perennial cold-climate strawberry (Fragaria ×ananassa) production systems: conventional matted row (CMR), advanced matted row (AMR), and cold-climate plasticulture (CCP). Replicate plots of each system were maintained for two harvest seasons. Volunteers harvested subplots in each system and completed a survey to evaluate pick-your-own consumer preferences. The CCP system was preferred by a majority of consumers in the first year, whereas the AMR system was rated highest in the second year. Preferences were positively correlated with ease of harvest and fruit appearance and negatively correlated with the percentage of fruit unfit for harvest. Fruit quality measurements made on marketable fruit in the second harvest season indicated that there were no treatment differences in titratable acidity or soluble solids concentration, but significantly lower fruit firmness in the CCP treatment compared with CMR and AMR.