bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal Changes in Specific Leaf Weight and Leaf Anatomy of Apple
Authors: Wooge Jon D. , Barden John A.
Published: September 2022

Newly expanded interior canopy leaves of apple (Malus domestica Borkh.) had lower specific leaf weight (SLW), leaf thickness, palisade depth, and number of palisade cell layers than middle or peripheral leaves from late May to early October. Leaves on the periphery of the canopy had the highest SLW values at all sample dates. Differences in leaf SLW, leaf thickness, and palisade depth between interior and peripheral leaves increased as the season progressed, primarily due to increases in peripheral leaves that developed later in the season. Regression analysis showed SLW to be significantly correlated with leaf thickness and palisade depth.
Summer Drought Response and Rooting Depth of Three Cool-season Turfgrasses
Authors: Sheffer K. M. , Dunn J. H. , Minner D. D.
Published: September 2022

This study was conducted to determine root distribution, soil moisture depletion, and 32P uptake, as an indicator of water absorption, by Kentucky bluegrass (Poa pratensis L. ‘Fylking’), perennial ryegrass (Lolium perenne L. ‘Manhattan’), and tall fescue (Festuca arundinacea Schreb. ‘Kentucky 31’). 32P was injected at 6, 18, 30, 42, and 54 cm from the soil surface under each turfgrass plot on 18 July 1978. Leaf blade radioactivity revealed differences in uptake among species, but was inconsistent with rooting patterns. Root mass measurements below 36 cm in late August showed tall fescue > perennial ryegrass > Kentucky bluegrass. Root mass above 12 cm showed Kentucky bluegrass > tall fescue = perennial ryegrass. Soil water content (SWC) at three depths in August reflected root distribution for the three species. SWC was lowest under Kentucky bluegrass and highest under tall fescue at 6 cm. At 54 and 78 cm, SWC was highest under Kentucky bluegrass and lowest under tall fescue. SWC was better than 32P injection for detecting species differences in water uptake.
‘Shore Gold’ Sweet Potato
Authors: Sterrett S. B. , Graves B. , Savage C. P. , Cooler F. W.
Published: September 2022

‘Shore Gold’ sweet potato [Ipomoea batatas (L.) Lam.] was developed by the Virginia Polytechnic Institute and State Univ. Experiment Station. It is an early, widely adapted, high-yielding sweet potato cultivar with excellent baking quality.
‘Biloxi’, ‘Miami’, and ‘Wichita’ Lagerstroemia
Authors: Egolf Donald R.
Published: September 2022

‘Biloxi’, ‘Miami’, and ‘Wichita’ are the first introduced tree growth habit Lager-stroemia indica L. × L. fauriei Koehne cultivars that combine mildew resistance, dark trunk bark coloration, and a range of flower colors. Lagerstroemia, commonly referred to as crape-myrtle, is the primary southern summer-flowering small tree, traditionally associated with the colonial era as was the lilac (Syringa vulgaris L.) in the northern frontiers. Crape-myrtle no longer is just a summer-flowering tree, but is a year-round landscape plant with magnificent trunk bark coloration. ‘Natchez’ and ‘Muskogee’ (4), the first U.S. National Arboretum L. indica × L. fauriei hybrids, have become leading nursery production and landscape plants as much for spectacular trunk bark coloration as the flowers. On the other hand, ‘Tuscarora’ (5) and ‘Tuskegee’ (6), both of similar parentage, lack intense bark coloration but are noteworthy cultivars because of the unique coral to dark pink flowers. More recently, the growth habit diversity was extended by the release of ‘Acoma’, ‘Hopi’, ‘Pecos’, and ‘Zuni’ with semi-dwarf growth habits (7). ‘Biloxi’, ‘Miami’, and ‘Wichita’ bring to 17 the U.S. National Arboretum Lagerstroemia cultivar introductions (2, 3).
Commercial Production of Horticultural Crops in Florida
Authors: Sheehan T. J. , Barrett J. E. , Krezdom A. H. , Reitz H. J. , Hochmuth George J.
Published: September 2022

Florida's ornamental horticulture industry, like the vegetable and fruit industries, has been shaped by Florida's long growing season, mild winters, and high light levels.
Horticultural Curricula can Benefit from National Initiatives
Authors: Hegwood Donald A. , Merritt R. H.
Published: September 2022

Two primary purposes of education are to satisfy the quest for knowledge and to provide educated and trained persons to serve the needs of society. These purposes also constitute an important part of the mission of a horticulture teaching program. In recent years, this mission has become more difficult to achieve, being challenged by declining enrollments, reallocation of positions, operating resources for teaching, inadequate facilities, and the diminishing half-life of new knowledge brought about by rapid advances in science and technology. The challenge also comes from institutional and societal pressures to look beyond disciplinary boundaries in both teaching and research.
Influence of Lantana on Growth of Various Citrus Rootstocks
Authors: Singh Megh , Achhireddy N. R.
Published: September 2022

Under nonlimiting conditions for nutrients, water, and light, the growth of citrus rootstocks was generally less in the presence of lantana (Lantana camara L.) than when they were grown alone. Approximately 75% of the rough leaves plants died within 3 months. Cleopatra mandarin was the least-affected rootstock with about 20% reduction of the root and shoot dry weights. The growth of Milam, sour orange, and Swingle citrumelo was intermediate in the presence of lantana. Overall, the presence of lantana did not affect nitrogen content of roots, whereas nitrogen levels in shoots varied for the six rootstocks.
Effect of Root Pruning at Different Growth Stages on Growth and Fruiting of Apple Trees
Authors: Schupp James R. , Ferree David C.
Published: September 2022

Three- and 4-year-old ‘MeIrose’/M.7A apple trees were root-pruned on two sides, 50 cm from the trunk, at a depth of 35–40 cm at one of the following growth stages: dormant, full bloom, June drop, and preharvest. Root pruning at dormant or full bloom growth stages reduced trunk cross-sectional area increase and shoot length, reduced average leaf size and fruit size, and increased yield efficiency. Dormant root pruning increased the level of Ca in the fruit flesh. Root pruning at June drop and preharvest had no influence on shoot growth, but increased preharvest fruit drop. Root pruning at full bloom or later increased fruit soluble solids. Considerable root regeneration in close proximity to the cut was evident in November on trees root pruned at the dormant and full-bloom stages. Root regeneration was less on roots pruned at June drop and minimal in preharvest-treated trees. Leaf mineral nutrient levels were not influenced by root pruning treatment. Vegetative growth and fruit size were reduced less by root pruning in the 3-year-old trees than in the 4-year-old trees.
Summer Pruning Affects Fruit Quality and Light Penetration in Young Peach Trees
Authors: Miller Stephen S.
Published: September 2022

Two-year-old peach trees [Prunus persica (L.) Batsch cv. Candor] on ‘Lovell’ rootstock were summer-pruned (selective thinning and heading of current season's growth) 23 days before harvest. Pruning did not affect fruit quality. Summer pruning increased yield the subsequent year, apparently by increasing fruiting wood in the center of the tree. Summer pruning vigorous 3-year-old ‘Loring’ peach trees 8 weeks before harvest increased PAR through the canopy, 1 m above the ground, immediately after pruning and when measured at harvest. Fruit from summer-pruned ‘Loring’ were firmer, with lower soluble solids than those not summer-pruned.
Computer-assisted Determination of Apple Tree Canopy Volume
Authors: Miller Stephen S. , Lightner Gary W.
Published: September 2022

A method for determining canopy volume of apple trees is described in which a graphics computer is used to digitize photographs of young trees. Volume is calculated from a formula based on the first theorum of Pappus. Volumes obtained compare favorably with the laborious, detailed hand-measurement methods. Canopy volumes determined from defined geometric shapes were generally less than those from hand- or computer-generated methods. Both of the latter methods correlated with trunk circumference and trunk cross-sectional area. Geometrically determined canopy volumes did not correlate with trunk size.
Effect of Early Season Foliar Sprays of GA4+7 on Russeting and Return Bloom of ‘Golden Delicious’ Apple
Authors: Meador Daniel B. , Taylor Bradley H.
Published: September 2022

Early season multiple spray applications of 5, 10, or 20 ppm of gibberellins A4+7 (GA4+7) reduced the severity and frequency of russet on four strains of ‘Golden Delicious’ apple (Malus domestica Borkh) fruit at three locations over 1, 2, or 3 years. The distribution of fruit in the U.S. extra fancy and fancy categories (graded for russet only) increased with increasing concentration of GA4+7 sprays. Regression analysis of data pooled from seven trials predicted for the 5-, 10-, and 20-ppm GA4+7 sprays, respectively, 68%, 74%, and 76% of the fruit falling in the combined extra fancy and fancy grades as compared to 40% on the untreated control trees. Additional experiments revealed tank-mixing GA4+7 with pesticides reduced the degree of russet suppression in one trial, but not in another. Return bloom was diminished on trees sprayed with GA4+7 in the previous year and the flower cluster density was inversely related to GA4+7 concentration. Chemical names used: (1α,2β,4aα,4bβ,10β)-2,4a,7-trihydroxy-1-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (GA4+7); polyoxyethylene-polypropoxypropanol dihydroxypropane (Regulaid).
Effects of Supplementary Lighting on the Growth and Flowering of Clematis
Authors: French C. J. , Lin W. C.
Published: September 2022

Clematis × ‘Jackmanii’ (C. lanuginosa × C. viticella × C. × eriostemon) and Clematis × ‘Comtesse de Bouchard’ (cultivar of C. × ‘Jackmanii’) were evaluated for winter flowering with supplementary lighting treatments combining two photoperiods and two levels of irradiance during September to January. The dormancy of ‘Jackmanii’ was overcome by long (16 hr) days or by high (HPS) irradiance during natural photoperiods (8.5-12 hr); the dormancy of ‘Comtesse de Bouchard’ was overcome only by long days, irradiance having no effect. Terminal flower bud formation was affected similarly by supplementary lighting. The development of lateral flower buds of both cultivars was greatly enhanced by combining long photoperiods and high irradiance.
Effect of Core Cultivation on Preemergence Herbicide Activity in Bermudagrass
Authors: Johnson B. J.
Published: September 2022

A field experiment was initiated to determine herbicidal activity on large crabgrasses (Digitaria sanguinalis (L.) Scop.] when core cultivation was performed in a common bermudagrass [Cynodon dactylon (L.) Pers.] turf after herbicide application. Core cultivation treatments were made prior to preemergence herbicide application or at 1, 2, 3, or 4 months after the chemicals were applied. Where oxadiazon (4.4 kg·ha−1), bensulide (11.2 kg·ha−1), bensulide + oxadiazon (6.7 + 1.7 kg·ha−1) and benefin (3.4 kg·ha−1) were applied, the timing of core cultivation had no significant influence on preemergence large crabgrass control. DCPA (14.0 kg·ha−1) was ineffective in controlling large crabgrass, regardless of core cultivation parameter. Chemical names used: 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon); 0,0-bis(1-methylethyl)S-[2-[(phenylsulfonyl)amino] ethyl]phosphorodthioate (bensulide); N-butyl-N-ethyl-2,6-dinitro-4-(trifluoromethyl)benzenamine (benefin); dimethyl 2,3,5,6-tetrachloro-1,4-benzenedicarboxylate (DCPA).
Effects of Paclobutrazol on Growth and Flowering of Bouvardia humboldtii
Authors: Wilkinson R. I. , Richards D.
Published: September 2022

Plant height of potted Bouvardia humboldtii Hort. was controlled effectively by foliar or drench applications of paclobutrazol. Three foliar applications of 250 mg·liter−1 paclobutrazol or a drench of 2 mg/100-mm-diameter pot reduced plant height by≈30% and increased the total number of flowers per plant by ≈35%. Overall, paclobutrazol significantly reduced total plant dry weight, and sprays were more inhibitory than drenches. Paclobutrazol altered the shoot : root ratio in favor of the shoot. Foliar sprays of daminozide (5000 mg·liter−1) or chlormequat (2000 mg·liter−1) were ineffective in controlling growth or flowering. It is concluded that paclobutrazol application may be a useful technique in the commercial production of Bouvardia as a flowering pot plant. Chemical name used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-l-ethanol [paclobutrazol (ICI-PP333)].
Chemical Weed Control in Gypsophila
Authors: Gilreath J. P.
Published: September 2022

Postemergence and preemergence herbicides were evaluated for crop phytotoxicity and weed control in seepage-irrigated ‘Bristol Fairy’ gypsophila (Gypsophila paniculata L.). DCPA, napropamide, pronamide, and oryzalin were severely injurious to gypsophila. Metolachlor, oxyfluorfen, alachlor, and oxadiazon provided varying degrees of weed control and did not reduce plant vigor or yield. Best weed control was provided by two applications of 4.48 kg·ha-1 oxadiazon. Chemical names used: dimethyl tetrachloroterephthalate (DCPA); 2-(napthoxy)-N, N-diethylpropionamide (napropamide); 3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide (pronamide); 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin); 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); 2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide (alachlor); 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon).
Changes in Ascorbic Acid Content of Blackspot-resistant and -susceptible Potatoes Following Bruising
Authors: Thornton Michael K. , Workman Milton
Published: September 2022

Experiments were conducted to determine if changes in tuber ascorbic acid content following bruising were related to blackspot susceptibility in potato (Solanum tuberosum L.). Tubers of four potato clones were bruised at three locations. Ascorbic acid content of bruised and nonbruised tissue on the same tubers was determined 0, 3, 6, 12, and 24 hr after bruising. Differences in initial ascorbic acid content between clones were highly significant, but not related to blackspot susceptibility. Differences in ascorbic acid content between bruised and nonbruised tissue of a tuber were significant in two of the four clones. Changes in ascorbic acid content of tubers with time occurred to a similar extent in bruised and nonbruised tissue. This experiment indicates that factors other than ascorbic acid content may determine differences in clonal susceptibility to blackspot.
In Vitro Micropropagation of Eucalyptus sideroxylon
Authors: Burger David W.
Published: September 2022

Nodes from field-grown coppice regrowth and mature trees of Eucalyptus sideroxylon were cultured on a modified Murashige and Skoog medium containing BAP and NAA. BAP (2-4 μm) and NAA (0.5-1.0 μm) were most effective in promoting axillary shoot proliferation from coppice and adult tissues. IBA was more effective than NAA in stimulating the formation of adventitious roots from in vitro-derived shoots. Plantlets from tissue culture were easily transferred to the greenhouse environment. Chemical names used: N6-benzylaminopurine (BAP); 1-naphthaleneacetic acid (NAA); 1H-indole-3-butanoic acid (IBA).
Tree-row-volume Spraying Rate Calculator for Apples
Authors: Byers R. E.
Published: September 2022

Most pesticide recommendations for apple orchards have been based on a specified rate per hectare. These recommendations are based on dilute applications of materials in 3740 liters·ha−1 (400 gallons/acre) to trees in a “standard” orchard, which are about 6.1 m (20 ft) high, 7.0 m (23 ft) wide, and 10.7 m (35 ft) between rows (3, 6). Most orchards today do not conform to this standard, and many pesticides are applied at concentrations other than dilute.
Growth Potential of Young Olive with High Chloride Irrigation Water
Authors: Robinson F. E.
Published: September 2022

This project was initiated to evaluate the growth potential of young olive using available high-Cl groundwater with microspray irrigation on a mixed hyperthermic Typic Torripsament of the Rositas fine sand series (8) in an arid climate (5, 6).
Pyracantha × ‘Pueblo’
Authors: Egolf Donald R.
Published: September 2022

Pyracantha × ‘Pueblo’ is the sixth disease-resistant cultivar introduced by the U.S. National Arboretum. Pyracantha, also referred to as firethom because of the brilliant, colored fruit clusters on a thorny plant, is one of the most showy berried shrubs in autumn. Firethom landscape merit is not restricted to the autumn and early winter but extends throughout the seasons with dense evergreen foliage that is further highlighted by profuse, cream-white bloom in early May. The previously introduced cultivars are ‘Shawnee’, NA 28179 (1), ‘Mohave’, NA 32225 (2); ‘Navaho’, NA 38451; ‘Teton’, NA 38450 (3); and ‘Apache’, NA 48240 (4).
‘Sumas’ Strawberry
Authors: Daubeny Hugh A.
Published: September 2022

‘Sumas’ is a new strawberry cultivar released from the breeding program at the Agriculture Canada Research Station, Vancouver, B.C. In trials throughout the Pacific Northwest it has been noted for high yields and fruit qualities that compare favorably with those of ‘Totem’, currently the most widely grown cultivar in the region. Plants of ‘Sumas’ are winter hardy, show a high level of virus tolerance, and some resistance to red stele caused by Phytophthora fragariae Hickman. These traits will contribute to longevity of plantings. ‘Sumas’, an Indian word meaning “a big level opening,” now refers to Sumas Prairie, which is the fertile farm land at the eastern extremity of the B.C. Lower Mainland strawberry production region.
Observations on Communication Barriers Facing New Researchers at Off-campus Locations
Authors: Wilcox-Lee Darlene
Published: September 2022

Certain barriers limit communication and intellectual stimulation for a new researcher located at an off-campus facility. Most of these limitations are, of course, directly related to distance, a very real physical barrier. When located off-campus, communication resources often taken for granted can be quite distant: a library, for instance, or seminars, which serve to keep you abreast of what is going on outside your immediate area of expertise. When off-campus, you are removed from interaction with faculty and graduate students, visiting post-docs, and fellows. In short, in an off-campus location, you are removed from the healthy flux of people and ideas that comprise the academic community of which you are a part.
Nitrogen Fertilization
Authors: Jones J. Benton
Published: September 2022

In the Feb. 1987 issue of HortScience 22:34-36, I was interested in the paper by Charles A. Mullins entitled “Effects of Nitrogen Fertilization on Production of Mechanically Harvested Snap Beans”. However, I found that two very important items of significance were not given:

The form of N applied was not given. It would be assumed that the N fertilizer was applied at seeding, although this was not specifically indicated. The form of N can have a marked effect on the response of snap bean to applied N.

Soil-testing information was given, but no identification of the method of extraction. Therefore, the values reported are meaningless without knowing how the test result was obtained. Such details are significant if the reader is to use the findings reported.
Apples on the Lincoln Canopy—Mechanized Management
Authors: Dunn John S. , Stolp Martyn
Published: September 2022

The Lincoln canopy method of training apple trees originated at the New Zealand Agricultural Engineering Institute during a program to mechanize the production of fresh-market-grade fruit. Work began in 1970. The shallow formalized tree form that results and the easy access that it offers from below and above have simplified the imposition of mechanized processes for spraying, pruning, and harvesting. This form, and a tree density of ≈ 1000/ha, a continuous canopy width of 3 m, and the ease with which branches can be developed and positioned to produce a full canopy all contribute to high light interception and a high yield potential.
Control of Necrotic Leaf Blotch and Premature Leaf Drop in ‘Golden Delicious’ Apples
Authors: Ducroquet Jean-Pierre
Published: September 2022

‘Golden Delicious’ apple (Malus domestica Borkh) foliage is subject to necrotic leaf blotch (NLB) associated with premature leaf drop with up to 50% defoliation at harvest time. In Santa Catarina State, Brazil, incidence of this physiological disorder could be reduced significantly by spraying with ziram, a fungicide containing 19% metallic zinc. An oil paste formulation of ziram was especially effective. The addition of zinc oxide (0.1%) to spray mixture at 2-week intervals further reduced the rate of premature leaf drop. When zinc oxide was added to ziram oil paste fungicide, premature leaf drop was reduced from 41% for the worst treatment down to 4.7%.
Response of Potted Plants and Vegetable Seedlings to Chlorinated Water
Authors: Frink C. R. , Bugbee G. J.
Published: September 2022

Eleven species of potted foliage plants, eight species of potted flowering plants, and four species of vegetable seedlings were tested for their response to irrigation with chlorinated water containing 0, 2, 8, 18, 37, or 77 mg·liter-1 residual chlorine. Growth and appearance were determined after 12 weeks for potted plants and after 6 weeks for seedlings. When compared with the control, growth of geranium and begonia declined at 2 mg·liter-1; pepper and tomato at 8 mg·liter-1; kalanchoe, lettuce, and tradescantia at 18 mg·liter-1; broccoli, marigold, and petunia at 37 mg·liter-1; and Swedish ivy, impatiens, madagascar palm, and english ivy at 77 mg·liter-1. The appearance of the plants followed a similar pattern. Germination of vegetable seeds was not affected by any of the chlorine treatments. Thus, current water chlorination practices with residual chlorine concentrations <1 mg·liter-1 should not adversely affect either the growth or appearance of most potted plants and vegetable seedlings grown in soilless media.
Reactions of Muskmelon Cultigens to Myrothecium roridum
Authors: Kuti J. O. , Ng T. J , Bean G. A.
Published: September 2022

The reactions of 50 cultivars and breeding lines of muskmelon (Cucumis melo L.) to inoculation with a pathogenic strain of Myrothecium roridum Tode ex Fries were evaluated using detached leaf tissues from greenhouse plants and immature fruits from field-grown plants. Leaf susceptibility was characterized by chlorosis, necrosis, and extensive fungus sporulation, whereas fruit susceptibility was evidenced by host tissue decay and fungus sporulation. Differences in reactions among muskmelon cultigens using detached leaves were consistent among tests and correlated well with susceptibility of young, immature fruits. Tolerance appeared to decrease with increasing physiological age of the immature fruits. ‘Hales Best’ exhibited the greatest tolerance, whereas ‘Summet’ was very susceptible.
Resistance in Wild Lettuce to Lettuce Infectious Yellows Virus
Authors: McCreight James D.
Published: September 2022

Lactuca saligna L., Lactuca serriola L., and Lactuca virosa L., which are cross-fertile with cultivated lettuce (L. sativa L.) were tested for resistance to lettuce infectious yellows virus in greenhouse and field tests. Fifteen of 25 L. saligna accessions were resistant, whereas 50 accessions of L. serriola and seven accessions of L. virosa were susceptible.
Thickness and Cell Layer Number of the Pericarp of Sweet Corn and Some of Its Relatives
Authors: Tracy W. F. , Galinat W. C.
Published: September 2022

Thirty six cultivars of corn (Zea mays L.) and three of its relatives (northern teosinte, Tripsacum dactyloides L., and Coix lachryma-jobi L.) were evaluated for pericarp thickness and number of cell layers in the pericarp. Both traits were examined using a light microscope. Pericarp thickness ranged from 50 to 185 pm and cell layer number from 5 to 22 within the 36 cultivars; pericarp thickness and cell layer number were positively and highly significantly correlated (r = 0.93**). The three relatives of corn had pericarps with 2 to 3 cell layers totaling 30 μm in thickness.
An Improved Firmness Tester for Juicy Fruit
Authors: Lustig I. , Bernstein Z.
Published: September 2022

The firmness tester for juicy fruit measures firmness by the compression of the fruit between two parallel surfaces with a measured force until a given applanation area is reached. An improved hydrostatic measuring head for this instrument is described that allows the direct determination of this area instead of the measurement of its diameter in the optical head formerly used. The firmness index is defined as the applied force per unit applanation area. Examples of firmness measurements of Prunus avium L., Vitis vinifera L., and Carica papaya L. are given.
Human Stress Reduction Through Horticultural Vocational Training
Authors: Doxon Lynn Ellen , Mattson Richard H. , Jurich Anthony P.
Published: September 2022

Five physiological measures of stress were made of 20 developmentally disabled adults working in a greenhouse or training center. Systolic and diastolic blood pressure, electrodermal response, and finger skin temperature were significantly lower for adults in the greenhouse as compared to the training center. Pulse rates were significantly lower after training had occurred. Vocational training of mentally retarded adults in a greenhouse environment could lead to healthier, more productive workers.
Farming Systems Research Training in Swaziland
Authors: Bevacqua Robert F.
Published: September 2022

Farming systems research (FSR) methodology is being used to improve vegetable production in Swaziland, a developing nation in southeastern Africa. An important prerequisite for this new' thrust in methodology is the training of staff in FSR objectives and processes.
15Nitrogen Uptake by Grapes with Divided Roots Growing in Differentially Salinized Soils
Authors: Taylor R. M. , Fenn L. B. , Pety C. A.
Published: September 2022

Several different split-root techniques, both horizontal zonation (1, 3, 6) and vertical zonation (2, 4, 7, 8), have been employed to study plant growth and water and nutrient uptake from differentially salinized root zones. High salinity level in one portion of the root zone may not affect overall plant performance if other portions of the root zone are relatively salt free (1, 3, 8). With uniform salinization, sodium chloride concentrations up to −0.8 MPa did not affect the 15N absorption rate in cotton, but osmotic pressures of −1.2 MPa substantially reduced it. However, water uptake and plant growth were affected to a greater extent than was 15N absorption (5).
Dormancy Terminology
Authors: Denney James O.
Published: September 2022

In James O. Denney’s letter regarding dormancy terminology (HortScience 22:197, Apr. 1987), the last diagram was drawn incorrectly.
“Endo-, Para, and Ecodormancy: Physiological Terminology and Classification for Dormancy Research”
Authors: Lang Gregory A. , Early Jack D. , Martin George C. , Darnell Rebecca L.
Published: September 2022

In the article “Endo-, Para-, and Ecodormancy: Physiological Terminology and Classification for Dormancy Research” by Gregory A. Lang, Jack D. Early, George C. Martin, and Rebecca L. Darnell (HortScience 22:371–377, June 1987), in the second column of Table 5 under part III-B (paradormancy), the term “Cryogenic endodormancy” should be changed to “Cryogenic paradormancy”.
Principles of Gas Exchange in Bulky Plant Tissues
Authors: Solomos Theophanes
Published: September 2022

Determination of diffusivity of gases in bulky plant tissues is of both theoretical and practical interest. For instance, a precise knowledge of O2 diffusion is needed for studying the nature of “oxidases” that may be involved in fruit respiration and also for predicting minimum O2 levels that can be safely used in controlled atmosphere (CA) storage. Further, a precise knowledge of the internal concentration of ethylene may be useful in determining the maturity of apples before harvest (15). Principles and techniques used for determining resistance to gas diffusion in bulky plant organs, and some practical applications for CA storage of apples are presented here.
Production of Modified Atmospheres in Deciduous Fruits by the Use of Films and Coatings
Authors: Smith Steve , Stow John , Geeson John
Published: September 2022

A range of techniques are used to preserve postharvest quality of fruit, vegetables, and other perishable produce. Refrigeration is the principal technique used but, in some instances, low temperature alone may be insufficient to retard ripening of fruit and prevent detrimental quality changes. Moreover, low temperatures for prolonged periods may lead to physiological damage, e.g., low temperature breakdown in apples (14). Pioneering work of Kidd and West (23) led to the development of controlled atmosphere (CA) storage, a sophisticated technique that extends the life of some produce more than refrigeration alone. CA storage is used mainly for apples (40), although recommendations for other fruits (15) and vegetables (16) can be found. Where CA techniques are applied, the concentrations of CO2 and O2 are controlled at optima specific for each cultivar, facilitated by the recent development of automatic control systems (22). However, both refrigeration and application of CA techniques are expensive, requiring large capital outlay for installation and maintenance and high energy inputs, especially for cooling. Moreover, it is not practical to provide equipment for CA control or refrigeration for small quantities of produce or individual fruit. Thus, once produce is harvested or removed from storage, it is subject to ambient conditions during marketing, which often lead to rapid quality deterioration.
Two Methods of Studying Rest: Temperature Alternation and Genetic Analysis
Authors: Dennis Frank G.
Published: September 2022

Explaining the physiological basis of rest or endodormancy (23) in seeds and buds has been the goal of considerable research effort within the past 40 years. One of the most popular approaches has been to study hormonal control, based on the hypothesis that growth-inhibiting compounds accumulate in buds and seeds as growth slows or seeds mature, and that these are metabolized, or that growth promoters are synthesized, or both, during subsequent exposure to rest-breaking treatments (moist chilling, dry after-ripening, exposure to light, etc.)
Performance of ‘Swiss Bartlett’ Pear on Several Old Home × Farmingdale Quince and Seedling Rootstocks in British Columbia
Authors: Denby L. G. , Meheriuk M.
Published: September 2022

‘Swiss Bartlett’ pear (Pyrus communis L.) was evaluated on Old Home × Farmingdale (OH × F) rootstocks 34, 69, 87, 130, 230, 333, and 515; EM Quince A and LePage C Quince, and Old Home and Bartlett seedlings planted in 1974 at 2.4 × 4.8 m. All trees on OH × F 51 were winter-killed within 2 years of planting and thus could not be evaluated. Marketable yields from 1975 to 1979 inclusive showed OH × F 87 to be the most precocious rootstock, followed by OH × F 515, 34, and 69. Yields from 1975 to 1984 inclusive were highest for OH × F 87, 515, 34, and 69, but were not significantly different from each other. Tree size, as indicated by trunk cross-sectional area, was largest for OH × F 515 and 34, followed by OH × F 87 and 69. Tree efficiency values as recorded for the trees in their 5th and 10th year of production were higher for OH × F 87, OH × F 69, EM Quince A, and Lepage Quince C than for most of the other rootstocks.
The Effects of Nutrient Solution Sterilization on the Growth and Yield of Hydroponically Grown Lettuce
Authors: Schwartzkopf Steven H. , Dudzinski Diane , Minners R. Sjhon
Published: September 2022

Two methods of removing bacteria from hydroponic nutrient solution [ultraviolet (UV) radiation and submicronic filter] were evaluated for efficiency and for their effects on lettuce (Lactuca sativa L.) production. Both methods were effective in removing bacteria; but, at high intensity, the ultraviolet sterilizer significantly inhibited the production of plants grown in the treated solution. Bacterial removal by lower intensity UV or a submicronic filter seemed to promote plant growth slightly, but showed no consistent, statistically significant effect.
Temporal Relationships of Watermelon Mosaic Virus 2 Inoculation Date and Symptom Appearance and Yield in Yellow Squash
Authors: McLeod Paul , Scott H. A. , Morelock T. E.
Published: September 2022

In field studies, appearance of foliar symptoms in yellow squash (Cucurbita pepo L., cv Sundance) provided a better indication of time of watermelon mosaic virus 2 (WMV-2) inoculation than appearance of symptoms in fruit. Although the longest period of time between inoculation and foliar symptom appearance occurred with the last inoculation date (25 Sept.), differences in this period did not differ statistically among inoculation dates. Dates of fruit symptom appearance were more variable and were more related to plant developmental stage than to time of inoculation. The length of disease-free fruiting period and the number of disease-free fruit were reduced severely for plants receiving one of the first four weekly WMV-2 inoculations. Subsequent inoculations failed to reduce squash yield significantly.
Seasonal Development of the Leaf Canopy of ‘Macspur McIntosh’ Apple Trees
Authors: Forshey C. G. , Weires R. W. , VanKirk J. R.
Published: September 2022

Leaf canopy development of 7- and 10-year-old- ‘Macspur McIntosh’/M.7 apple (Malus domestica Borkh) trees was studied in 1986. All growing points were counted on six trees of each age at budbreak and at appropriate intervals thereafter. The growing points were divided into old spurs, new spurs, terminal shoots, lateral shoots, and bourse shoots. Only old spur leaves were present from budbreak to pink; at pink, terminal shoots could be distinguished; at petal fall, the other three types could be identified. Shoot leaves averaged nearly 50% larger than spur leaves and made up 36.8% of the leaf numbers and 45.7% of the leaf area at full leaf. The leaf canopy was 10% complete at full bloom and 23% complete at petal fall. Total leaf area/tree increased 8-fold in the 4 weeks after full bloom.
Seed Germination of Alaska Iris, Iris setosa ssp. interior
Authors: Holloway Patricia S.
Published: September 2022

Seeds of Alaska iris, Iris setosa Pall. ssp. interior (Anders.) Hult., were collected from wild stands near Fairbanks and subjected to the following treatments: 0 or 125 days of stratification; 24-hr soak in water or 1000 mg·liter-1 gibberellic acid (GA3); alternating (25°/10°C) or constant (21°) temperatures; and germination in darkness or light. After 7 days, germination was best (95.0%) with stratified seeds that were soaked in GA3 and germinated at constant temperatures in the dark. A greenhouse study in which stratified seeds were soaked in water or GA3, sown in a commercial peat and vermiculite seed germination mix, and germinated beneath clear or black plastic confirm ed that germination was highest (64.4%) and most uniform (83.3% filled container cells) with the com bined treatments of GA3 and darkness.
Effect of Gibberellic Acid on Flowering and Quality of Double Persian Violet
Authors: Neumaier Evamaria E. , Blessington Thomas M. , Price James A.
Published: September 2022

Three experiments were conducted with double-flowering Persian violet (Exacum affine Balf.) to evaluate the effet of gibberellic acid (GA) applied at different flower bud sizes, developmental stages (ages) of the plant, and application frequencies. In Expt. 1, the greatest number of flowers was produced in plants with 8-mm bud size, with the largest flower diameter obtained with 4-mm bud size. Treatment with GA increased the number of flowers. Flower diameter was greatest with a GA concentration of 125 ppm. Plant quality of GA-treated plants was best when sprayed at 8-mm bud size with a concentration of 125 ppm. In Expt. 2, plants treated at 12 weeks after transplanting had the most flowers. Flower diameter decreased for all treated plants and all age groups in comparison with non treated plants. GA at 125 ppm produced the largest increase in number of flowers and maintained a large flower diameter. Plants treated 8 weeks after transplanting with 125 ppm GA had the most desirable plant size and flowering characteristics. In Expt. 3, a single application of 125 ppm GA was the most effective in contrast to multiple applications for flower induction, number of flowers, and flower diameter.
Influence of Ice Nucleation Temperature on the Freezing of Peach Flower Buds
Authors: Ashworth Edward N. , Davis Glen A.
Published: September 2022

The freezing behavior of peach [Prunus persica (L.) Batsch] flower buds was influenced by the temperature at which ice formation was initiated. Buds seeded with ice just below 0°C were more likely to exhibit deep supercooling, and water in the primordia would supercool to lower temperatures than in unseeded excised flower buds. This effect was not always expressed and varied with the stage of acclimation. Researchers using differential thermal analysis to estimate bud hardiness will need to evaluate this effect. Seeding specimens with ice may be warranted to obtain results comparable with field conditions.
Evaluation of Rutabaga Cultivars for Turnip Mosaic Virus Resistance and the Inheritance of Resistance
Authors: Shattuck V. I. , Stobbs L. W.
Published: September 2022

Rutabaga (Brassica napus L. Group Napobrassica) cultivars were screened for resistance to turnip mosaic virus (TuMV), and the inheritance of resistance was studied. Immunity and resistance were found in four of 49 rutabaga cultivars evaluated. The cultivar ‘Sensation’ was immune to the Ontario strain of TuMV. In crosses between susceptible ‘Laurentian’ and resistant Line 165 and susceptible triazine-resistant ‘Laurentian’ and Line 165, TuMV resistance was determined by a single dominant gene.
‘Aylés’, ‘Guara’, and ‘Moncayo’ Almonds
Authors: Felipe A. , Sodas i Company R.
Published: September 2022

Three new self-compatible, late-blooming cultivars of almond [Prunus amygdalus Batsch, syn. P. dulcis (Mill.) D.A. Webb] have been released from the almond breeding program that is being developed at the Unidad de Fruticultura of Zaragoza (1). One of the main objectives of this program is to obtain late-blooming, self-compatible cultivars in an attempt to solve widespread problems of inadequate cross-pollination and spring frosts. The shell of these almonds is hard, fitting very well into the Spanish market, which is almost exclusively based on hard-shelled cultivars.
Summary and Future Direction: Chemical Regulation in Tissue Culture
Authors: Reynolds John F.
Published: September 2022

This series of papers has expanded upon Skoog's milestone discovery regarding the roles of cytokinins and auxins in morphogenesis of in vitro systems. One of the effects of adenine-based cytokinins in culture systems is the formation of adventitious shoots or the expression of axillary shoots. This symposium reported that a cytokinin response also can be observed by using phenylurea-based cytokinins. Two phenylurea compounds, thidiazuron and 4PU–CI, were illustrated as having strong cytokinin activity, equivalent to or surpassing the adenine-based compounds. One of the effects of these diphenylureas is the formation of autonomous callus. These observations were used to speculate on the mode of action of the phenylureas as being stimulation of endogenous cytokinin biosynthesis (or metabolism), resulting in altered cytokinin levels. Other studies indicate that the phenylureas and adenine cytokinins may have similar action sites, hence similar effects.
Vegetable Cultivar Evaluation in England and Wales: Developments and Economies
Authors: Milbourn Graham , Holland Roger
Published: September 2022

The oversupply of agricultural commodities, including vegetables, in the United Kingdom has led the government to urge decreases in expenditures on the official cultivar testing program. At the same time, the submission of new lines by breeders into the test program continues unabated. In summarizing the vegetable cultivar assessment program, as carried out in England and Wales by the National Institute of Agricultural Botany (NIAB), both for the statutory National Listing requirements and for the production of Recommended Lists for vegetable growers, the emphasis therefore will be on the development of new techniques, particularly with a view to cost savings.
Seasonal Occurrence and Recovery of Phytophthora fragariae in Infected Strawberry Roots
Authors: George S. W. , Milholland R. D.
Published: September 2022

Strawberry (Fragaria × ananassa Duchesne) plants of the susceptible cultivar Tennessee Beauty were planted in naturally infested soil in a grower's field in 1985 and in microplots in 1986. From bimonthly examinations, oospores of Phytophthora fragariae were detected microscopically in infected strawberry roots from January through May in 1985 and 1986, with the maximum number observed in March. Oospores developed in root steles primarily during those months when the soil temperature was ≥16°C. Eighty-five percent of the bait plants of ‘Tennessee Beauty’ became infected when planted in infected soil removed from microplots in Mar. 1986 and incubated for 30 days at 15°. The fungus was isolated from 45% of these plants.
Root Development, Water Stress, and Yield of Mechanically Harvested Apple Trees
Authors: Glenn D. M. , Miller S. S. , Peterson D. L.
Published: September 2022

The purpose of this study was to determine if over-the-row mechanical shake-catch harvesting affected root development, leaf water stress, and yield of young ‘Golden Delicious’/M.7A and ‘Law Rome’/MM.111 apple (Malus domestica Borkh.) trees. Leaf water potential and temperature differential (canopy-air temperatures) were not significantly altered by mechanical harvesting. A minirhizotron technique did not detect changes in root distribution or root morphology. The fruit yield was unaffected by mechanical harvesting for four harvest years. No deleterious effects were detected as a result of over-the-row shake-catch harvesting.
Influence of Aeration, Topdressing, and Vertical Mowing on Overseeded Bermudagrass Putting Green Turf
Authors: Mazur A. R. , Wagner D. F.
Published: September 2022

Field studies were conducted for 4 years on putting green turf to determine the influence of cultivation practices on the transition from overseeded perennial ryegrass (Lolium perenne L. ‘Yorktown II’) turf to hybrid burmudagrass [Cynodon dactylon (L.)Pers. × C. transvaalensis Burtt-Davies] in the spring. The cultivation practices of core aeration, vertical mowing, and topdressing were shown to have no positive influence of increasing the rate of bermudagrass coverage during the spring on bermudagrass greens overseeded with perennial ryegrass. The verticut treatment resulted in decreased bermudagrass coverage as well as a reduction in turf quality. All cultivation practices resulted in some quality loss at various times during the spring transition period compared to the control.
Evaluation of Postemergent Grass Herbicides for Use in Annual Flower and Ground Cover Plantings
Authors: Teriy Graber Debra A. , Hensley David L.
Published: September 2022

Fifteen species of annual flowers and two ground covers were treated with sethoxydim (0.31 and 0.62 kg·ha−1), fluazifop-butyl (0.28 and 0.56 kg·ha−1), haloxyfop-methyl (0.14 and 0.28 kg·ha−1), crop oil (2.35 liter·ha−1), surfactant [0.25% (v/v)], and water, and phytotoxicity was evaluated in a greenhouse screening trial. In a separate study, three species of field-planted annual bedding plants and one ground cover received two applications of the same treatments. Field-grown plants were evaluated for phytotoxicity and growth. Phytotoxicity was variable with species and chemical. In both studies, however, geranium (Pelargonium ×hortorum L.H. Bailey) and celosia (Celosia cristata L.) were damaged by fluazifop-butyl and haloxyfop-methyl. Annual periwinkle (Catharanthus roseus L.) was injured by sethoxydim. Chemical names used: [1-(ethoxyimino)buty]-5-(ethyIthio)propyl]-3-hydroxy-2-cyclohexen-l-one (sethoxydim);(±)-2[4-[[5-(trifluoromethyl)2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop-butyl); methyl 2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (haloxyfop-methyl).
Influence of Irrigation Interruptions on Flowering of Hippeastrum × hybridum ‘Red Lion’
Authors: Boyle Thomas H. , Stimart Dennis P.
Published: September 2022

Irrigation interruptions of 0, 2, 4, or 8 weeks were imposed on actively growing ‘Red Lion’ amaryllis (Hippeastrum × hybridum) bulbs to determine the influence of water stress on flowering. Withholding irrigation for 4 or 8 weeks was effective in promoting early flowering of first and second scapes compared to continuously irrigated plants. Irrigation interruptions of 2, 4, or 8 weeks resulted in first scape flowering on all plants by 160, 140, or 60 days, respectively, after resumption of irrigation. Only 83% of continuously irrigated plants flowered within 160 days. Water stress treatments did not influence total number of flowering scapes per plant produced in 160 days nor number of flowers per umbel. Irrigation interruption affected timing of flowering by promoting scape extension and floral development.
Use of Ethylene Production for Harvest-date Prediction of Apples for Immediate Fresh Market
Authors: Blankenship Sylvia M. , Unrath C. R.
Published: September 2022

‘Starkrimson Delicious’ and ‘Golden Delicious’ apples (Malus domestica Borkh.) were harvested weekly in 1983, 1984, and 1985; sealed in containers; and measured daily for ethylene accumulation over a 6-day period (or until ethylene reached ≥2.0 μl·liter−1). The number of hours to accumulate minimums of 0.2, 0.5, 1.0, or 2.0 μl·liter−1 were calculated from daily readings and were regressed against date of sample harvest. When the number of hours required to accumulate a selected ethylene level began to decline, a linear equation using the first declining point and previous point was generated and used to predict a harvest date for immediate fresh-market use. Predicted harvest dates were compared to harvest dates selected by a taste panel. Out of 12 predictions made over a 3-year period using an ethylene level of 0.2 μl·liter−1, predicted harvest dates for ‘Golden Delicious’ were within 4 days of the taste panel harvest date on three occasions. In ‘Starkrimson Delicious’ there were five accurate predictions out of 12; however no single minimum level of ethylene gave successful predictions. Overall, it does not appear that this method accurately predicts harvest dates for ‘Starkrimson Delicious’ or ‘Golden Delicious’ destined for immediate sale on the fresh market.
Evaluation of Techniques to Measure Chilling Injury in Tomato
Authors: Kamps Terry L. , Isleib T. G. , Herner R. C. , Sink K. C.
Published: September 2022

Intact plants of four Lycopersicon species, Solanum lycopersicoides Dun. and a L. esculentum Mill. × S. lycopersicoides intergeneric hybrid at the four- to 11-leaf developmental stage were subjected to temperatures of 20° or 2.5°C for 72 hr. Plants were assayed for chilling injury by a visual rating of damage on specified leaflets (VRL), chlorophyll fluorescence (CF), electrolyte leakage (EL), and a visual rating of plants (VRP). Correlations of genotypic effects were significant between a) CF and VRL, b) CF and VRP, c) VRL and VRP, and d) VRP and EL. Correlations of the temperature × genotype interactions were highly significant between a) CF and VRL, b) CF and VRP, and c) VRL and VRP. CF was the most precise assay to quantify chilling injury. The means for CF for each of five leaflets from a single leaf produced similar separation of genotypes. Chilling resistance of an intergeneric hybrid between sensitive L. esculentum Mill. cv Sub-Arctic Maxi and resistant S. lycopersicoides suggested dominant, nuclear gene control.