Search Results
Abstract
‘Royal Red Cherry’ and ‘Short Red Cherry’ are indeterminate, fruitful and multiple disease resistant tomato cultivars. ‘Royal Red Cherry’ is similar to ‘Large Red Cherry’ and ‘Jumbo Cherry’ in fruit size and quality, but is a more prolific yielder. ‘Short Red Cherry’ has a more compact vine type that is based on the brachytic (br) gene and it is most desirable for the patio, container gardener. ‘Short Red Cherry’ is generally earlier in production pattern than ‘Royal Red Cherry’.
Abstract
Retention and early growth of ovaries of tomato cultivar Earlipak No. 7 (L. esculentum, Mill.) and a related breeding line were recorded for several weeks at 4 locations. Percent fruit-set, defined as the percentage of flowers of which ovaries were retained and reached a diameter of at least ¼ inch in 2 weeks, was not a reliable index of either ovary retention or early ovary growth. Important information concerning the fruiting of tomato may be lost, when data are collected on the basis of the defined fruit set rather than observed ovary retention and ovary growth specifically.
Five- to six-year-old `Redblush' grapefruit (Citrus paradisi Macf.) trees on `Volkamer' lemon [VL = C. volkameriana (Ten. & Pasq.)] or sour orange (SO = C. aurantium L.) rootstock, were grown individually in 7.9-m3 lysimeters for 2.5 years using low to high rates of fertilizer N. Net CO2 assimilation (ACO2) of leaves and leaf dry mass per area (DM/a) increased with leaf N concentration, whereas leaf tissue C isotope discrimination (Δ) decreased. Leaf tissue Δ was negatively related to ACO2 and DM/a. Transient effects of rootstock on leaf N were reflected by similar effects on Δ. There was no effect of leaf N on water-use efficiency (WUE) of leaves (WUEL = ACO2/transpiration); WUEL was not correlated with Δ. Although photosynthetic N use efficiency (ACO2/N) consistently decreased with increased leaf N, Δ was not consistently related to ACO2/N. Annual canopy growth, tree evapotranspiration (ET), and fruit yield increased with whole tree N uptake. Leaf tissue Δ was negatively related to all of these tree measurements at the end of the second year. By that time, whole-tree WUE (WUET, annual canopy growth per ET) also was negatively related to Δ. Larger trees on VL had higher ET than trees on SO, but there were no rootstock effects on WUET or on Δ. Leaf tissue Δ was consistently higher than Δ values of trunk and woody root tissues. Citrus leaf tissue Δ can be a useful indicator of leaf N, characteristics of leaf gas exchange, tree growth, yield, and WUET in response to N availability.
Abstract
Scanning electron microscopy revealed the presence of stomata, trichomes, scars left by detached trichomes, and epidermal cells on the surface of fresh, pickling cucumbers. Size, frequency and distribution of stomata were determined. Stomata, recessed several qm, were the only apparent, natural openings in the epidermis for gas exchange. Stomata were most numerous in the middle (20.2/mm2), less in the blossom end (10.4/mm2) and essentially absent in the stem end section of large (3.8–5.1 cm diameter), ‘GY14’ fruit. Stomatal frequency on large fruit was only about one-third that on small (1.9–2.7 cm diameter) fruit, but the stomatal index for the middle section of each size was similar (0.17–0.18). Large ‘GY14’ fruit were estimated to contain 130,000 stomata, with potential stomatal pore area (assuming open guard cells) representing 0.062% of the fruit surface
Research was conducted to evaluate the performance of a hydraulically driven turfgrass sod strength machine equipped with a force transducer to measure various strength parameters. The most commonly reported strength parameter, peak force (PF), continued to provide the quickest and easiest measurements of sod strength. Calculations of work involving the continuous measurement of sod strength over the duration of the stretch did not consistently improve the information provided by the PF measurement. Changes in sod bed pull speeds altered the calculations of work, whereas pull speed changes generally had little effect on force measurements, an important consideration for sod strength measurement devices that have limited control of sod bed pull speed. The unit was marginally successful in distinguishing sod strength differences between St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze.] treated with various levels of pyridine herbicides. The device also provided strength parameters that distinguished the relative strengths of four warm-season turfgrass sods.
Small-scale vegetable farmers are interested in cover crops and reduced tillage, but scale-appropriate technology and equipment are necessary to expand these practices to the growing segment of small farms. We sought to determine the efficacy of tarps, an increasingly popular tool on small farms, to end overwintering cover crops and provide weed suppression for subsequent no-till cabbage production. In three fields over two seasons in Maine, we grew a winter rye (Secale cereale L.) and hairy vetch (Vicia villosa L.) cover crop, which we managed by a factorial combination of tillage (no-till, till) and tarping (tarp, no-tarp) in June, followed by a transplanted cabbage crop (Brassica oleracea L. var. Capitata) in July. Within each treatment, subplots were either weeded by hand or left unweeded. Cover crop biomass ranged from 2.8 to 4.5 Mg⋅ha−1. Mean cabbage weights in the novel no-till system (no-till/tarp) were greater than (year 1) or equal to (year 2) those in tillage-based systems (till/no-tarp and till/tarp). In year 1, the mean cabbage weight in weeded subplots was 48% greater in no-till/tarp than in till/no-tarp systems. In unweeded subplots, this difference was 270%, highlighting the efficacy of the no-till/tarp system to reduce the impact of weeds. In year 2, weed biomass was higher with all treatments than it was in year 1, and unweeded subplots failed to produce marketable heads (i.e., >300 g). The mean cabbage weight in weeded subplots was equal among no-till/tarp, till/tarp, and till/no-tarp systems. Tarping had a strong effect on weed biomass and weed community composition measured at the time of cabbage harvest in unweeded subplots. In year 1, weed biomass at the time of cabbage harvest with tarp treatments was less than half that with no-tarp treatments. Tarps effectively facilitated the cover crop mulch-based no-till system. We propose that this system is an adaptive strategy for farmers affected by climate change. However, both cover crop production and tarping shorten the growing season. We discuss tradeoffs and opportunity costs using the metric of growing degree days.
Abstract
Surveys were made of Li in leaves, irrigation water and soil in groves of 37 to 43 year old ‘Marsh’ grapefruit on sour orange rootstock. Lithium in leaves increased during the late summer. Leaves with 50 to 60 ppm Li in September generally developed necrotic lesions on margins below the tip in November when they contained 60 to 90 ppm Li and abscissed within 1 to 4 months. Lithium varied widely between spring-cycle leaves on the same tree and within the leaf where it accumulated in the lesions. Severe Li toxicity symptoms were associated with 0.18 to 0.25 ppm Li in the irrigation water, 0.7 to 1.0 ppm in the soil and from 68 to 232 ppm in spring-cycle leaves in November. Vigorous growth and high yields occurred with 24 to 34 ppm Li in the leaves, 0.07 to 0.11 ppm Li in the irrigation water and 0.3 to 0.4 ppm in the soil. Severe leaf symptoms with Li content as high as 175 ppm were induced by soil applications of LiCl under field conditions.
Abstract
For the tomato cultivar ‘Earlipak No. 7’, measurements were made on several components which contribute to variations in harvest patterns. Components which were observed at 4 locations were: per cent of ovaries retained; the per cent of these which grew and matured; the sizes of ovaries at selected periods of time; the variance in this component; the elapsed time between flower and maturity, and between interim stages; the variances in these components. Sizes and seed numbers of matured fruits were observed. Correlation coefficients among the variates are presented. It appears that measurements upon each of the components and at least one more (flower production rates) are essential to a fundamental understanding of variations in the harvest pattern on a genetic or environmental basis. The apparent influence of seed number on growth rates and mature weight is brought into question.
Abstract
In a collaborative study at 5 North American locations, treatment with 12% CO2 and 3 to 5% O2 for 2 weeks at 0° to 3°C at the beginning of controlled atmosphere (CA) storage significantly delayed softening of ‘McIntosh’ apples (Malus domestica Borkh.). Softening was retarded further when treatment time and CO2 concentration were increased, and when fruit was harvested less mature. The effect was diminished by treatment at 0°, and was nullified by delayed treatment and slow cooling during treatment. Softening response to CO2 was not influenced by O2 concentration or storage humidification during treatment. CO2 treatment reduced the rates of CO2 and ethylene evolution from the fruit, even after 4 to 5 months of subsequent CA storage, but affected neither soluble solids nor titratable acidity of fruit after storage. When taste panelists could distinguish CO2-treated from nontreated CA apples, they preferred the treated fruit.
These beneficial results were usually accompanied by external CO2 injury, and occasionally by internal CO2 injury; 30 to 50% of the fruit were injured in some tests. Treatment in a non-humidified room reduced CO2 injury without also reducing treatment benefits. We conclude that for ‘McIntosh’, the potential for injury outweighs the benefits obtained from CO2 pre-treatment in CA storage.
In the mid-1980s, a statewide educational program was initiated to help improve productivity in replanted apple orchards. This effort began with a study of the background of the problem in Washington and an assessment of the problems growers faced when replanting orchards. An array of potential limiting factors were identified-most important, specific apple replant disease (SARD)-but also low soil pH, poor irrigation practices, arsenic (As) spray residues in the soil, soil compaction, nematodes, nutrient deficiencies, and selection of the appropriate orchard system. The educational program was delivered using a variety of methods to reach audience members with different learning styles and to provide various levels of technical information, focusing on ways to correct all limiting factors in replant situations. Results have been: Acceptance of soil fumigation as a management tool: increased recognition of soil physical, chemical, and moisture problems; reduced reliance on seedling rootstock, and an increase in the use of dwarfing, precocious understocks; and better apple tree growth and production in old apple orchard soils.