bluuebunny/crossref_metadata_2025 huggingface dataset:
THE GENETICS AND BREEDING FOR SALT TOLERANCE IN MELON, CUCUMIS MELO.
Authors: Mendlinger Samuel , Pasternak Dov
Published: October 2019

The increasing salinity of both irrigated lands as well as irrigation water in many parts of the world have emphasized the importance of having appropriate breeding strategies for developing salt tolerant cultivars. In a program to breed for salt tolerance (high yield and good quality at 5,000 ppm salinity) in melons, several breeding strategies were tried. The only systems that succeeded was using combining abilities in a hybrid program. We found that salinity did not effect the number of fruit or fruit quality but only fruit weight. Fruit weight of hybrids grown in fresh water was controlled by dominant genes (h2=0.09) whereas the same hybrids grown under salinity had fruit weight control by additive genes (h2=0.54) Therefore, we were capable of breeding tolerant hybrids from non-tolerant parents.
PHOTOSYNTHESIS, RESPIRATION, AND CARBON COST OF DEVELOPING RABBITEYE BLUEBERRY FRUIT
Authors: Birkhold Keith , Darnell Rebecca , Koch Karen
Published: October 2019

Carbon exchange and content of blueberry (Vaccinium ashei) fruit were measured from anthesis through fruit ripening in order to determine the amount of imported carbon required for fruit development. Net photosynthesis occurred in blueberry fruit from petal fall through color break. During this time, gross photosynthesis of fruit decreased from 30.1 μmol CO2·g fw-1·hr-1 to 4.8 μmol CO2·g fw-1·hr-1, and dark respiration decreased from 14.3 μmol CO2·g fw-1·hr-1 to 4.6 μmol CO2·g fw-1·hr-1. After color break, the photosynthetic rate fell to zero, and the respiration rate increased to 8.0 μmol CO2·g fw-1·hr-1, before decreasing. Preliminary data suggest that fruit photosynthesis contributes 11% of the total carbon required (dry weight gain + respiratory loss) during fruit development however, it supplies 50% of the total carbon required during the first 5 days after petal fall. This contribution of carbon from fruit photosynthesis may be critical in initial fruit development since the current season's vegetative growth is not yet providing carbohydrates.
OUTLOOK FOR MECHANIZATION IN SMALL FRUIT CROPS
Authors: Mainland Charles
Published: October 2019

Mechanized harvest for processing markets has become commercially accepted for blackberries (Rubus sp.), highbush (Vaccinium corymbosum), lowbush (V. angustifolium) and rabbiteye (V. ashei), blueberries, cranberries (V. macrocarpon), grapes (Vitus labruscana, V. vinifera, V. rotundifolia, V. sp.), raspberries (Rubus ideaus) and to a lesser extent for strawberries (Fragaria × ananassa). Fruit bruising during harvest and sorting often contributes to reduced “eye appeal” and keeping quality for fresh sales. Highbush and rabbiteye blueberries are successfully machine harvested for fresh markets, however, high temperature and rain will often make product quality unacceptable. Highbush blueberries grown in cool climates and rabbiteye blueberries with greater inherent resistance to bruising have most consistently given acceptable quality. Cultivar improvement and equipment that causes less bruising during harvest and sorting will be required for increased mechanization for fresh markets. Mechanical pruning of blackberries, blueberries, grapes and raspberries can reduce costs by up to 80%. The audience will be involved in discussion of advancements in mechanization techniques.
EFFECT OF STORAGE CONDITIONS ON NON-ETHYLENE VOLATILES IN ORANGES AND TOMATOES
Authors: Baldwin Elizabeth A. , Nisperos-Carriedo Myrna O.
Published: October 2019

Edible lipid and composite films were tested for their ability to retain flavor volatiles in `Pineapple' orange fruits stored at 21° using a headspace analysis technique. Volatiles, considered to be important to fresh orange flavor, were quantified and acetaldehyde, ethyl acetate, ethyl butyrate and methyl butyrate increased progressively during storage in coated fruits. Acetaldehyde increased by the second day of storage in uncoated fruits but declined thereafter, `Sunny' tomato fruits were harvested at the green or breaker stage of maturity and ripened at 32.5, 21.0 and 12.9°C. Some fruit from the higher and lower storage temperatures were moved to 21° after one week. In most cases major or important flavor volatiles were highest in fruit transferred to or continuously stored at 21.0°C followed by 12.9 and 32.5°C. Fruit harvested at the breaker stage generally had higher volatile levels compared to those harvested green.
CONTROL AND MEASUREMENT OF PLANT FUNCTIONS BY COMPUTER-BASED ENVIRONMENTAL MANIPULATION
Authors: McFarlane Craig , Pfleeger Thomas
Published: October 2019

Chambers were developed to study the uptake, accumulation and phytotoxicity of environmental pollutants. Each is connected to the computer and other support facilities by quick connects which allow the laboratory to be configured in various ways depending on experimental design. Each chamber consists of two isolation compartments connected only by plant stems. Electronic instruments are used to monitor key physiological processes of both the roots and shoots during the course of plant exposure. The computer controls the exposure conditions (i.e. day length, temperature, nutrient pH, CO2 concentration, etc.) as well as continuously collects information about plant responses (i.e. photosynthetic and transpiration rates). Photosynthesis, transpiration, and mineral nutrient uptake can be individually controlled by manipulating the environment and thus allowing their study in combination with additional stressors. The computer used to accomplish these tasks will be discussed along with other examples of computer use for plant manipulation.
WATER-USE TRENDS AND DISTRIBUTION IN THE U. S., 1950-85
Authors: Solley Wayne
Published: October 2019

Water use in the United States increased from 1950 to 1980 and decreased from 1980 to 1985, on the basis of estimates compiled at 5-year intervals by the U.S. Geological Survey. Total withdrawals of freshwater and saline water during 1985 were 1,510 million cubic meters per day, a rate more than double that estimated for 1950 and 10 percent less than that estimated for 1980. For most categories, the rate of increase in water use declined from 1970 to 1975 and from 1975 to 1980. Withdrawals for thermoelectric-power generation and irrigation, the two largest categories of use, were 13 and 6 percent, respectively, less during 1985 than during 1980. The combined total for industrial, commercial, and mining water use during 1985 was 25 percent less than during 1980--the lowest combined estimate for these categories since the compilations began in 1950. The decrease in water use during 1985 compared to 1980 can be attributed to the following important factors:

Streamflow generally was more plentiful during 1985 than during 1980 because of more rainfall; this reduced the dependence on ground water in many areas and the need to irrigate in some areas.

The economic slowdown, improved plant efficiencies, depressed commodity prices, and new technologies that require less water decreased the requirements for industrial and irrigation water.

Enhanced awareness by the general public to water resources and conservation programs in many States probably reduced water demands.
IMPLEMENTATION OF MICROIRRIGATION FOR CITRUS PRODUCTION IN FLORIDA
Authors: SMAJSTRLA ALLEN G.
Published: October 2019

The use of microirrigation in Florida citrus production has increased rapidly in recent years. Most new groves are now being developed with microspray or drip irrigation. Many existing sprinkler and seepage (subirrigation) systems have also been converted to micro irrigation. Although water management districts have encouraged the use of micro irrigation for water conservation, research results which solved problems with the practical implementation of this technology and which demonstrated economic incentives are primarily responsible for its popularity in Florida citrus production. Research programs have (1) developed management techniques to eliminate emitter clogging, (2) demonstrated the effective use of microspray systems for freeze protection, (3) increased young tree growth with respect to conventional irrigation methods, (4) demonstrated the cost-effectiveness of microirrigation, and (5) developed management techniques for efficient use of water and nutrients in fruit production.
Utilizing a GIS Vegetation Model for a Campus-as-arboretum Development
Authors: Creech D. , McDonald D. , Kulhavy D. , Blackwell P.
Published: October 2019

This paper outlines the history of the SFA Arboretum's effort to establish a campus-as-arboretum at the university. In 1996, the participants created a robust Geographic Information System (GIS) for the campus forest based primarily on a 1993-95 campus mapping and tree inventory project in the 144-acre main core of the campus (Wilson to North St.; College to Starr). The project served as the MS thesis of Susan Perkins. In brief, the campus model reveals a pine-dominated Type 2 forest (one rapidly approaching maturity), difficult campus hydrology issues, and a landscape low on diversity with 68 species represented. In 1996, the Arboretum's AutoCAD® map and Excel® tree data files were integrated into the College of Forestry Unix-based ArcInfo® platform. This now provides full GIS capabilities for landscape planners. The resultant maps based on user queries reveal a robust vegetation analysis and management tool. In 1997, the SFA administration, Physical Plant, Grounds, College of Forestry, and SFA Arboretum initiated a “campus beautification” funding campaign. The SFA Arboretum will play a key role in building unique, documented, and mapped woody ornamental collections for the campus. This provides a unique opportunity in the South for long-term Zone 8 woody plant evaluation in a high-visibility and “perpetual” landscape.
Cluster Modification Effects on the Performance of an Arkansas Table Grape Selection
Authors: Woodburn K.R. , Clark J.R.
Published: October 2019

Flower cluster thinning effects were investigated on A-2274, a large-fruited, seedless table grape selection from the Univ. of Arkansas Grape Breeding Program. The objective of the study was to evaluate flower cluster thinning as a method to enhance cluster size and fill. Treatments included thinning to one flower cluster per shoot, removing one-half of each cluster, and a control (no flowers removed). Each treatment consisted of three, single-vine replications, with each vine being pruned to 32 buds. Removal of entire flower clusters (to one per shoot) resulted in larger clusters and a trend toward higher cluster fill ratings. Berry mass, number of clusters per vine, and yield per vine were unaffected by flower cluster treatment. Berries per cluster were reduced by the partial flower cluster removal treatment. Flower cluster thinning to one cluster proved a beneficial practice in increasing cluster characteristics of this promising selection.
Comparative Organic Acid Profiles of Highbush, Southern Highbush, and Rabbiteye Blueberries
Authors: Magee J.B. , Gupton C.L.
Published: October 2019

The organic acid composition of blueberries of three highbush (Vaccinium corymbosum) cultivars, three rabbiteye (V. ashei cultivars and nine southern highbush (V. corymbosun hybrids) cultivars or selections was determined by HPLC. Species means off the individual acids (citric, malic, succinic, and quinic), expressed as a percentage of total acid, formed profiles or patterns that are thought to be characteristic of the species. Citric (75%) was the predominant acid in highbush fruit with lesser percentages of succinic (13%), quinic (9.6%), and malic (2.7%). The percent composition of rabbiteye berries [quinic (49%), succinic (39%), citric (6.7%), malic (5%)] was distinctly different from highbush. The acid profile of southern highbush fruit reflected their V. corymbosum heritage with an acid profile similar to that of highbush. When related to a clone's pedigree, these results suggest that organic acid profiles may be a useful screening tool for studying the contribution of southeastern native species such as V. darrowi or V. ashei to the inheritance of organic acids.
Reevaluation of a Desiccating Surfactant for Thinning Peach Blossoms
Authors: Ebel R.C. , Himelrick D.G. , Caylor A. , Pitts J.
Published: October 2019

The surfactant “Surfactant WK” (dodecyl ether of polyethylene glycol) was applied to peach trees [Prunus persica (L.) Batsch] at full bloom over 3 years. Blossoms died rapidly so that within 2 days dead blossoms could be distinguished easily from live blossoms or set fruit. There were strong (R2 > 0.87), linear correlations between concentration of “Surfactant WK” applied and percent blossoms removed and fruit set, which were similar over the 3 years. Trees were hand-thinned according to commercial practices after treatment. There was similar cropload, fruit weight, and yield across treatments at harvest indicating no negative effects by the chemical on productivity. There was only slight limb damage at the highest concentrations of “Surfactant WK,” which overthinned blossoms. We recommend that based on the effectiveness, consistency, and lack of significant phytotoxicity, “Surfactant WK” be reevaluated as a thinning chemical for peach trees.
The Use of Crumb Rubber as a Container Component for Lantana Production
Authors: Leader Kris M. , Owings Allen D. , Bush Edward W.
Published: October 2019

Lantana camara `New Gold', `Irene', and `Patriot Dove Wings' were planted in five pine bark-based media containing 0%, 12.5%, 25%, 37.5%, and 50% crumb rubber. Each medium was amended with 7.14 kg·m-3 dolomite lime, 0.892 kg·m-3 of Micromax, and 4.76 kg·m-3 of 17-6-12 Nutricote fertilizer. Height and visual quality ratings were taken at 4 and 8 weeks. Dry weights were taken when the experiment was terminated. There were no significant differences in height, visual quality, and dry weight of `New Gold' lantana for all crumb rubber rates. `Irene' grew taller and had higher visual quality rating in the 4th week with 12.5% and 25% crumb rubber. This trend continued in the 8th week with taller plants grown in 25% crumb rubber. However, there were no differences in plant quality. Dry weight of plants grown in 37.5% and 50% crumb rubber was reduced when compared to the control. There were no differences in growth or quality of `Patriot Dove Wings' at week four. At week eight a reduction in both height and visual quality occurred with 37.5% and 50% crumb rubber. Plant dry weights were also significantly reduced at >37.5% crumb rubber.
Conception and Development of the Carolina Children's Garden
Authors: Verkade Stephehs D. , Marturano Arlene
Published: October 2019

The Clemson University Sandhill Research and Education Center is one of four branch stations of the South Carolina Agriculture and Forestry Research System, with a mission to conduct research and extension education programs in urban ecology. The Carolina Children's Garden has been created in partnership with other state agencies, funding sources, and volunteers as a site for environmental education. Learning from gardens and landscapes has steadily decreased since the late 1940s and today the average child spends 6 hours at indoor pursuits at school, an equal number at the television or computer screen at home, leaving little time for outdoor exploration. Recently, children's gardens have been established around the county as resources to reconnect children with their environment. The 2-acre Carolina Children's Garden is an interpretive framework for visitors to experience gardening as a tool for bringing families in touch with nature, each other, and local environmental issues. A volunteer team designed and installed eight theme gardens, an entertainment stage, and picnic area as the first phase of this garden. Themes include Mesozoic Memories Dinosaur Garden, Three Bears Garden, Growing Healthy Garden, Butterfly Garden, McGregor's Garden, and Alphabet Garden. The development of the garden has generated community interest and positive media exposure, inspires lifelong appreciation of the natural environment, encourages replication of ideas, and facilitates family recreation in a learning environment.
Cotyledon Age and Somatic Embryogenesis of Cowpea
Authors: Marsh Lurline
Published: October 2019

Somatic embryogenesis can be used to facilitate the improvement of traits in plants. The study was conducted to assess different ages of immature zygotic cowpea (Vigna unguiculata (L. Walp), “MN13” cotyledons for their ability to produce somatic embryos. Cotyledons were harvested weekly for the first 8 weeks following anthesis. After removal of their embryo axes, they were cultured in Murashige and Skoog (MS) medium containing 0.6% agar, B-5 vitamins, 3% sucrose, and 20 mg·L-1 2,4-dichlorophenoxy acetic acid (2-4D). Cotyledon explants of all the ages produced calli. The percentage of explants producing calli ranged from 32% to 92%. On transfer of the calli to similar medium containing 0.2% gellan gum instead of 0.6% agar, all ages except those from the 1-week cotyledons produced white globular somatic embryos. The largest of these embryos were 9 mm in length. The highest frequency of globular embryos was produced with the 3- to 5-week-old cotyledons.
Controlling Deer Damage to Vegetable Crops with Organic Products
Authors: Simonne Eric , Owen John
Published: October 2019

Because deer pressure in Alabama is high, the efficacy of Garlic Barrier™ (GB) in controlling deer damage was evaluated with sweetpotato (SWP), southernpea (STP), sweet corn (SC), and zucchini squash (ZSQH). GB was applied on or around the plots at 10× the recommended rate. Damage was rated three times weekly on a 0 (0% damage) to 5 (100%) scale between 15 June and 18 Sept. All damage observed was unambiguously attributed to deer. GB on the plot significantly (P < 0.02) reduced grazing damage to SWP and STP, but not enough to prevent economical losses. Protection from GB around the plots was similar to the unsprayed control. Damage to SWP began 3 days after establishment. Damage to STP was limited to the developing pods. No damage was observed to SC and ZSQH (P > 0.37) during vegetative and reproductive stages. These results document scientifically the deer-repellent property of GB under natural conditions when applied directly on the plants. However, in its present formulation and under severe deer pressure, GB alone may not provide economical protection.
Soil Phosphorus Removal as a Function of Cropping System
Authors: Earhart D.R. , Baker M.L. , Haby V.A.
Published: October 2019

A factored experiment was established at the Texas A&M Univ. Research and Extension Center at Overton in Spring 1995. The objective was to investigate the use of warm- and cool-season legume cover crops in vegetable cropping systems for reducing phosphorus (P) accumulation from poultry litter (PL) and commercial blend (CB) fertilizer. PL rates were based on soil test nitrogen (N) requirement of the vegetable crop and percent N content of the litter. This was considered the 1X rate. Fertility treatments were applied to the vegetable crop only. PL was applied at O, 1X, 2X and 4X rates. CB was applied at recommended rates for N, P, and K. The vegetable crops were: Spring 1995—watermelon; Fall 1995—turnip; Spring 1996—tomato; Fall 1996—collard; Spring 1997—squash. The legumes were: spring—Iron and Clay cowpea; fall—crimson clover. Dry-matter yield of cowpeas and clover was not affected by fertility treatment in any of the years studied to date (Spring 1995, 1996, 1997). Plant concentration of P for both cover crops was increased all 3 years as rate increased. PL applied at the 1X rate maintained P levels in the surface 0—15 cm of soil at 60 mg·kg-1 over the five-season study period. CB maintained levels of P equal to the control. A cropping system of spring vegetable—fall legume greatly reduced P accumulation. A reduction in P was also noted from a system of fall vegetable—spring legume, but not as pronounced. The greatest accumulation was with a system of spring vegetable—fall vegetable.
Seeding Rate Affects Turnip Root Production
Authors: Bracy Regina P. , Parish Richard L.
Published: October 2019

A precision seeder (Stanhay Model 870) and a bulk seeder (Planet Jr.) were used to evaluate the effects of precision seeding, seed spacing, and row configuration on yield and grade-out of two cultivars of root turnips. Seed spacings for the precision seeder included within-row (WIR) spacings of 56, 112, and 168 mm in single plant line/row and 112 and 168 mm in two plant lines/row. Seed spacings with the bulk seeder were obtained by using 100% viable seed or a 50% viable: 50% killed seed mix. The experiments were conducted during the spring and fall on two rows on a 1.2-m-wide bed. Total yield was not affected by plant population or seeder. Plant population, however, caused a shift in yield among grades. Yield of culls increased as plant population increased. Yield of extra-large (>114 mm) roots decreased as plant population increased. Turnips seeded 168 mm apart in a single line/row yielded more extra-large and large (25-114 mm) grade roots and less medium (4-24 mm) and cull (<4 mm or misshapen) roots. More consistent results were obtained with the precision seeder than the bulk seeder. During both seasons, yield was lower for the hybrid (`Royal Crown') cultivar than for the open-pollinated (`Purple Top White Globe') cultivar.
Genotype × Environment (G × E) Interaction in Southernpea [Vigna unguiculata (L.) Walp] Genotypes in the Southeastern USA
Authors: Alleyne John C. , Morelock Teddy E. , Sneller Clay H.
Published: October 2019

Genotype by environment (G × E) effects in Regional Cooperative Southernpea trials for the southeastern United States were investigated to characterize the extent, pattern, and potential impact of G × E on seed yield of southernpea [Vigna unguiculata (L.) Walp] genotypes. The structure of G × E effects was investigated using the Additive Main Effect and Multiplicative Interaction (AMMI) method. AMMI analyses revealed a highly significant genotype × environment interaction, most of which was partitioned into a genotype × location component of variance. AMMI first principal component axis scores stratified environments into two groups that minimized variation within groups. Biological interpretation of groupings and visual assessment of the AMMI biplot, revealed high-yielding genotypes interacting positively with one group of environments and conversely, low-yielding genotypes interacting positively with the other group. There were some significant rank changes of genotypes as yield potential varied across environments. Some environments showed similar main effects and interaction patterns indicating that most of the G × E effects could be captured with fewer testing sites, and consequently redundancy of some testing environments over years.
Preliminary Evaluation of Extended Shelf-life Tomatoes under Tennessee Conditions
Authors: Coffey David L.
Published: October 2019

Eight extended shelf-life hybrid tomato cultivars, along with six conventional entries including the commercial cultivars, `Sun Leaper' and `Plum Dandy', were evaluated at The Univ. of Tennessee Agricultural Experiment Station. Plants of extended shelf-life cultivars had an indeterminate growth habit and were 18 cm taller than plants of the determinate conventional cultivars. Subjective ratings for disease incidence were less for extended shelf-life cultivars early in the season but were no different late in the season. Fruits were harvested at the pink stage over a 4-week period and graded by size according to the Los Angeles lug arrangement. Yields from extended shelf-life cultivars ranged from 2000 to 2666 with an average of 2394 boxes of marketable fruit per hectare. Yields from conventional cultivars averaged 2323 boxes of marketable fruits per hectare. Yields of fruits occurring in the 5 × 5 and larger size ranges were greater for the extended shelf-life cultivars, while the reverse was true with yields of fruits in the 6 × 6 range. Extended shelf-life cultivars produced more cull fruits than conventional cultivars. For firmness comparisons, fruits were selected from the 4 × 5 grade and stored at a temperature of 22 to 24 °C. Starting 2 days after harvest, fruits were subjectively evaluated at 2-day intervals by hand-squeezing, using a rating scale of 1-5, 5 being equivalent to that of the firmness of a mature green fruit of the same size category. Fruits of extended shelf-life cultivars were firmer at harvest and remained firmer during 12 days of postharvest storage than those of conventional cultivars.
Influence of Mechanical Scarification on Emergence and Seedcoat Adherence of `Genesis' Triploid Watermelon
Authors: Duval John R. , NeSmith D. Scott
Published: October 2019

Production of triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] transplants is hindered by low and nonuniform emergence, and seedcoat adherence. Seedcoat adherence leads to weakened and slow-growing plants. High seed costs are prohibitive to many transplant growers. Improvement of emergence would lower financial risks to growers and transplant producers. Mechanical scarification was examined as a means to decrease the impact of both problems. Seeds of `Genesis' triploid watermelon were placed in a cylinder with 100 g of very coarse sand and rotated for 6, 12, 24, and 48 hours at 60 rpm. Nontreated seeds were used as a control. Data were taken daily on emergence and seedcoat adherence. The experiment was repeated at three temperature regimes. No significant differences were observed in seedcoat adherence. Scarification, however, did significantly improve emergence under test conditions.
Adaption of a Spectrophotometric Assay for Pungency in Onion to a Microplate Reader
Authors: Boyhan George E. , Schmidt Norman E. , Woods Floyd M. , Himelrick David G. , Randle William M.
Published: October 2019

A spectrophotometric assay for pyruvic acid in onion has been adapted to a microplate reader. Correlations between the spectrophotometer and microplate reader ranged from 0.991 to 0.997 for sodium pyruvate standards and 0.899 to 0.934 for onion samples. Onion pungency values were slightly higher with the microplate reader for both sample and background compared to the spectrophotometer when both are used in the single wavelength mode. Comparing the spectrophotometer in the single wavelength mode to the microplate reader in the dual wavelength mode resulted in no statistically significant difference between them. Standards for both the microplate reader and spectrophotometer followed a quadratic function.
On-farm Demonstrations: A Simple Approach to Designing Drip Irrigation Systems for Small and Part-time Vegetable Growers
Authors: Kemble J.M.
Published: October 2019

Many small and part-time commercial vegetable growers in Alabama rely on rainfall to provide irrigation for their crops. This, coupled with limited financial resources, creates situations where poor-quality produce and low yields are common. Working cooperatively with county extension agents, growers that met a series of criteria and that could benefit from drip irrigation were identified. An on-farm result demonstration and educational program was developed to help combat this problem by emphasizing the importance of irrigation and introducing affordable drip irrigation systems for these growers. County agents and growers participated in an educational program, which involved a daylong course covering the basics of drip irrigation and hands-on training with all components of the drip system. Necessary background information on each site was collected and a drip irrigation system was designed for each site. Next, each grower was provided with all of the necessary materials and equipment needed to install the system. The overall flexibility in the basic design was stressed and several growers modified their systems with items that provided various levels of automation, or the capacity to fertigate. Fifteen on-farm demonstrations in 14 counties were developed ranging from 0.08 to 0.60 ha in size. Cost for this equipment (layflat, fittings, drip tape, regulators, filter) was ≈$230 per site. Success of each demonstration varied. Overall, growers were positive about using drip irrigation and that it was affordable. Most planned on continuing or expanding its use next season.
Yield Response of Watermelon to Plant Density
Authors: Duthie James A. , Shrefler James , Roberts Warren , Edelson Jonathan V.
Published: October 2019

In each of seven field experiments, density of watermelon (cultivar Sugar Baby) plants was varied over the range 1000-9000 plants/ha by varying the distance between plants in single-row, replicate plots. Per unit area, reproductive biomass and marketable yield each increased linearly with density. An upper limit on these response variables at high density was not detected in any experiment. The rate of increase per 1000 plants/ha ranged from 1.1 to 3.2 Mg·ha-1, for reproductive biomass, and from 0.5 to 1.1 Mg·ha-1, for marketable yield. The linear effect of density explained >90% of the increase in reproductive biomass in most experiments. The effect on marketable yield was more variable because the marketable fraction of reproductive biomass often was highly variable. In most experiments, the marketable fraction did not vary systematically with density. The linear rate of change in the marketable fraction with density did not exceed 3% per 1000 plants/ha on average in any experiment. Intraspecific competition intensified rapidly as density was increased in some experiments. Intensity of competition appeared to vary among environments.
Variable Resistance to Gummy Stem Blight in Watermelon PI 271778
Authors: Hall Melvin R. , Sumner Donald R.
Published: October 2019

Seeds from 19 selfed plants of watermelon PI 271778 were field-planted with seven cultivars in July 1997. Two weeks after planting, one seedling per plot was inoculated on 15 July by spraying to runoff (24 × 104 conidia/mL in water) a mixture of indigenous isolates of Didymella bryoniae. Plants were inoculated again on 31 July. On 7 Aug., plants with at least one stem lesion ranged from 0% to 96% (mean = 22%) for selections from PI 271778, while cultivars ranged from 3% to 71% (mean = 24%). On 19 Aug., plants with at least one stem lesion ranged from 12% to 100% (mean = 74%) for selections and 94% to 100% (mean = 97%) for cultivars. These differences were further reflected in average dead canopy of 25% for selections and 80% for cultivars on 3 Sept. By 17 Sept., dead canopy averaged 47% for selections and 100% for cultivars. Fruit harvested per plant averaged 2.5 for selections and 0.8 for cultivars. By harvest, vines were totally collapsed on all cultivars and on some selections, while stems of most selections were still vigorous but leaves exhibited significant necrosis.
Effects of Hydrogen Cyanamide (Dormex) and Ethephon (Ethrel) on Fruiting of `Redhaven' Peach
Authors: Powell Arlie A. , Pitts James , Boozer Bobby
Published: October 2019

Early flowering of peach in the Southeast can result in annual crop loss as a result of late winter—early spring freezes. It has been shown in peach and other Prunus that a fall application of ethephon delays flowering several days. However, delayed harvest and smaller fruit size of certain varieties may occur. Hydrogen cyanamide replaces lack of chilling in peach but can also advance harvest date and possibly enhance or maintain fruit size. A randomized complete-block experimental design using 12-year-old `Redhaven' trees was used to evaluate whether hydrogen cyanamide could offset the delayed harvest and smaller fruit size disadvantages of using ethephon without advancing bloom dates. Treatment combinations of ethephon (at 20%, 50%, and 90% of required chilling) and hydrogen cyanamide (at 90% to 100% of required chilling) were applied as whole-tree foliar sprays to near point of drip. Although nonsignificant, there were trends toward hydrogen cyanamide overcoming both smaller fruit size and delayed harvest induced by ethephon.
Mechanical Bloom Thinning as a Means to Reduce Hand Labor Needed to Thin Peaches
Authors: Boozer Robert T. , Ebel Robert C. , Pitts James A.
Published: October 2019

A Phil Brown Corporation, hydraulic operated rope thinner was evaluated in 1995 and 1997 to determine performance for bloom thinning under Alabama peach growing conditions. Using detailed pruned trees in 1995, the rope thinner removed 55% and 57% of the blooms from two double pass treatments and 42% from single pass. Thinning was 9% to 31% higher in the upper one-half of the fruiting zone. In 1997, nondetail pruned trees were used and ground speed was evaluated. Percent blooms removed by single pass were 28, 23, and 22 for 1.6, 3.2, and 4.8 km·h-1, respectively. Double pass clockwise removed 38% of the blooms at 3.2 km·h-1. Greatest time saving for follow-up hand thinning was 15 minutes per tree with double pass over hand-thinned only.
Soybean Oil as a Prebloom Flower Bud Thinner for Peaches
Authors: Reighard Gregory L. , Ouellette David R.
Published: October 2019

Survival of peach flowers during spring or winter freezes and large fruit size at harvest are critical for profitable peach production in the Southeast. Delaying both bud swell in late winter and flower phenology in spring reduces the risk of flower bud death from cold temperatures. Preliminary research in Tennessee using soybean oil (SO) as a dormant oil spray in place of Superior oil showed SO delayed peach bloom, thinned flower buds, and increased fruit size. In 1997, a `Harvester' peach orchard in Monetta, S.C., and a `Redhaven' orchard near Clemson, S.C., were sprayed in early February with 0%, 6%, 8%, 10%, and 12% SO mixed with 1% (by volume) Latron B-1956. Number of dead flower buds and the flower bud stages for each SO treatment were recorded during the first pink to full bloom flowering period. Excess fruit were hand-thinned in late April. Fruit set, maturity date, weight, and yield/tree were taken. Bud death increased from 14% (control) to 17% to 20% at the 8%, 10%, and 12% SO rates for `Redhaven' and from 13% (control) to 21% at the 10% and 12% rates for `Harvester'. Phenology was delayed 3-4 days for `Redhaven' at 8%, 10%, and 12% SO, but no differences were noted in the `Harvester' trees. No differences in fruit maturity occurred. Fruit weight and yield/tree was higher for all `Harvester' SO treatments and the `Redhaven' 10% and 12% SO treatments. No shoot phytotoxicity was observed.
Effect of Nitrogen Levels on Fruit Firmness and Plant Response of Hydroponicall y Grow n `Chandler ' Strawberries
Authors: Himelrick David G. , Ebel Robert C.
Published: October 2019

`Chandler' strawberry plants were established in a recirculating nutrient flow hydroponic system under six nutrient solution N levels (35, 70, 140, 210, 280, and 350 ppm). Various morphological and fruiting responses were measured. Average berry weight was greatest in the 280 ppm range and lowest in the 350 ppm solution N treatments. Percent soluble solids were greatest in the 35 ppm and lowest in the 140 ppm N treatments. Titratable acidity was greatest in the 75 and 210 ppm treatments and lowest in the 140, 280, and 350 ppm N treatments. Nitrate N was greatest in the juice of the 280 and 350 and lowest in the 35 ppm N treatment. Interior and exterior fruit firmness followed a general trend of the greatest firmness being found at 35 ppm and the least firm berries being from the 350 ppm treatment.
Four Grape Canopy Systems in Texas
Authors: McEachern George Ray
Published: October 2019

I. Chennin Blanc 107-cm bilateral cordon spaced 3.6 × 2.4 m, 1119 vines/ha, 14 spurs with 32 buds/vine. Yields were 8.8 t·ha-1 in the third leaf; 9.7 in the fourth, and 12.8 the 5th year, 1990, at the Jane Terrell Vineyard, Navasota, Tex. II. Cabernet Sauvignon with a two-trunk 122 cm bilateral cordon spaced 3.3 × 1.2 m, 2445 vines/ha with 48 buds/vine. Yields were 9.7 t·ha-1 for 1994 through 1997 at the mechanically harvested Newson Vineyard, Plains, Tex. III. Le Noir with a 91-cm trunk and a two-cane canopy; spaced 3 × 2.1 m, 1536 vines/ha, with 14 buds/vine. Yields were 13.3 t·ha-1 in 1996 and 11.2 in 1997 at Messina Hoff Vineyard, Bryan, Tex. IV. Merlot/110R with a 45° slanting cordon, 30 cm at south to 152 cm at north, spaced 1.5 × 1.5 m, 4308 vines/ha with 10 spurs and 20 buds/vine. Yield of 10.8 t·ha-1 in the third leaf, 1997, at Wolf Vineyard, Valley View, Tex. Four very different canopy systems were successful; the ideal system is yet to be determined.
Resistance to Chestnut Blight in the American Chinquapin
Authors: Norton J.D. , Dane Fenny
Published: October 2019

The American or Allegeny chinquapin (Castanea pumila) is native to the same area of the United States as the American chestnut (C. dentata) from Florida to Canada and westward to Arkansas. The high-quality nuts are an excellent source of food for wildlife and humans. Resistance to chestnut blight (Cryphnuectria parasitica) was discovered in seedlings in virgin forest at Elgin Air Force Base, Fla., with observations of plants for 35 years. A recurrent selection breeding program was established at Auburn Univ. to improve the blight resistance, precocity, dwarfism, pest resistance, cold hardiness, yield, and quality. A number of seedlings appear to be very promising selections for improvement of the American chinquapin. Since there is little information available regarding hereditability of certain traits in perennial tree species, results of breeding at Auburn Univ. should provide us with guidance for further improvement of the American chinquapin.
Light Distribution in Three Apple Training Systems as Affected by Cultivar and Rootstock
Authors: Allen Ray A. , Rom Curt R.
Published: October 2019

Light distribution in two cultivars on three dwarfing rootstocks in three high-density apple tree training systems was measured in the sixth leaf beginning at full bloom and continuing through the season. Training system had a significant effect on light penetration into the lowest point of the canopy (measured at 0.5 m), with the slender spindle being significantly darker than either the central leader or the vertical axis, although all three systems were below the threshold value of 30% full sun (FS) needed to maintain productivity for most of the season. Cultivar had no significant effect; however, trees of both `Jonagold' and `Empire' fell below 20% FS early in the season and remained there until late in the season. Rootstock had the greatest effect, with trees on M9 and M26 being significantly darker in the lower canopy than trees on Mark. Trees on M26 and M9 fell below 10% FS early in the season and remained there, while trees on Mark never fell below 20% FS.
Effect of Auxin and Wounding on Adventitious Root Formation of (Opuntia amyclaea) Cladodes
Authors: Lazcano Carlos A. , Davies Fred T. , Duray Sharon A. , Estrada-Luna Andres , Olalde-Portugal Victor
Published: October 2019

Mature cladodes of prickly-pear cactus (Opuntia amyclaea Tenore. cv. Reina) were treated with five wounding methods and four concentrations of potassium salt indolebutyric acid (K-IBA) to stimulate adventitious root formation. K-IBA from 4144 to 41,442 μm (1000 to 10,000 mg·L-1) increased root number and root dry weight; however, root length was decreased at 41,442 μm (10,000 mg·L-1). Root number and root dry weight were higher with wounding methods that had larger wounded surface areas. K-IBA altered rooting polarity and stimulated adventitious root formation along the wounded cladode surfaces. Treatments without suberization had a higher percentage of rotted cladodes. This research validates the commercial practice in Mexico of suberizing cladodes early in the propagation cycle. Auxin application could be of commercial benefit for enhanced rooting in the clonal regeneration of new selections for prickly-pear cactus orchards. The wounding methods and auxin treatments utilized make an excellent classroom demonstration for manipulating rooting polarity.
Plant Growth Retardants Reduce Peduncle Length of Achillea × `Coronation Gold'
Authors: Kessler J. Raymond , Keever Gary J.
Published: October 2019

Vegetative offsets of Achillea x `Coronation Gold' were rooted under mist for 3 weeks and potted into 10-cm pots in a greenhouse. Plants were grown under short photoperiods for 6 weeks before being vernalized for 6 weeks at 6 °C. Plants then were provided long photoperiods from night-break lighting. Foliar sprays of daminozide at 0, 2550, 5100, or 7650 mg·L-1, chlormequat at 0, 767, 1534, or 3201 mg·L-1, daminozide + chlormequat at 0, 1275 +, 2550 + or 3825+1534 mg·L-1, flurprimidol at 0, 40, 80, or 120 mg·L-1, paclobutrazol at 0, 32, 64, 96, 128, or 160 mg·L-1 or uniconizole at 0, 11, 22, 33, 44, or 55 mg·L-1 were applied as a spray 1 week after vernalization. Highest market quality ratings were achieved with paclobutrazol at 96 or 128, uniconizole at 22 or 33, daminozide + chlormequat 3825 + 1534, chlormequat at 2301 or flurprimidol at 40 mg·L-1. Peduncle length and growth index decreased linearly for daminozide, chlormequat, and daminozide + chlormequat, and decreased quadratically for flurprimidol, paclobutrazol, and uniconizole with increasing rate. Time to flower increased most in treatments receiving high rates of daminozide. Flower diameter was reduced by the highest rates of flurprimidol and paclobutrazol.
Growth of Tree Species in Response to Controlled-release Fertilizer Sources and Application Rates in a Commercial Nursery Setting
Authors: Owings Allen D. , Bush Edward W.
Published: October 2019

A study was initiated at Bracy's Nursery, Amite, La., in Apr. 1997 to evaluate the influence of seven controlled-release fertilizer sources and three top-dressed application rates in production of 4-gal (15.7-L) containers of `LaFeliciana' peach and swamp red maple. The fertilizers tested were Osmocote Plus 15-9-11, Osmocote Plus 16-8-12, Woodace 20-5-10, Woodace 20-4-11, Customblen 24-4-6, Nutricote (Type 270) 17-7-8, and Nutricote (Type 360) 17-6-8. Application rates were 1.75, 2.25, and 2.75 lb N per cubic yard. The experiment was completely randomized within blocks (species) and each treatment was replicated five times. A control treatment was also included. For `LaFeliciana' peach, Nutricote and Osmocote yielded the superior results when shoot height and visual quality ratings were determined in October (6 months after initiation). Increases in application rate did not significantly increase shoot height or visual quality ratings in most cases. For swamp red maple, shoot height was not affected by fertilizer source or application rate. Caliper ranged from 19.2 to 23.0 mm but was only slightly influenced by fertilizer source and application rate. Visual quality ratings were significantly higher for Osmocote Plus 16-8-12 when compared to some of the other fertilizer sources.
Nutrient Availability in Mulched Landscape Plantings
Authors: Mirabello R.A. , Einert A.E. , Klingaman G.L. , McNew R.W.
Published: October 2019

To examine the effects of mulching and fertilization on nutrient availability and plant growth in landscape beds, plots were established using four mulches (cottonseed hulls, cypress wood, pine bark, pine straw) and three fertilizer application methods (granular, liquid, time-release). Fertilizer was applied either below the mulch on the soil surface or over the mulch surface. Marigolds, Tagetes erecta L., were planted during the summer, followed by pansies, Viola×wittrockiana Gams, during the winter. Applied fertilizers, existing soil nutrients, and water-soluble nutrients from the new mulch provided an adequate supply of nutrients for marigold growth. Placement of fertilizer above or below the mulch did not affect marigold growth. Pansy growth was limited by depletion of soil N during the marigold season and by leaching of applied nutrients in the winter while plants were not actively growing. Mulch lowered soil temperatures and slowed pansy recovery in the spring. Pine straw allowed soil temperatures to rise earlier in the spring and improved pansy growth.
Micropropagation of Camptotheca acuminata
Authors: Lineberger Dan , Reed David , Rumpho Mary
Published: October 2019

Camptotheca acuminata (Chinese happy tree, Nyssaceae) is a source of the anticancer phytochemical, camptothecin. An endangered species in its native China, Camptotheca has been grown in this country on an experimental basis, but the germplasm base is extremely narrow. As a prelude to the establishment of a plant improvement effort designed to increase the efficiency of camptothecin production, in vitro studies that will enable plant regeneration and shoot proliferation from selected clones have been undertaken. Shoot proliferating cultures were established from shoot tip explants and were maintained on WPM medium containing 4 μm BA. MS medium and nodal explants proved unsatisfactory. Shoot proliferation was highest when in vitro shoot tips were cultured on 4 μm BA compared to media containing no growth regulator or the cytokinins zeatin, thidiazuron, or kinetin. In vitro—produced shoot tips were rooted by direct sticking in plastic containers filled with RediEarth mix, and were successfully adapted to the greenhouse environment.
A Mechanism for Rancidity Retardation by Partial Oil Extraction of Pecans
Authors: Kanamangala Ravindranath V. , Maness Neils O. , Smith Michael W. , Brusewitz Gerald H. , Knight Sue
Published: October 2019

Shelf life is a major problem in the marketing of pecans, particularly at the retail level. A procedure to extend the shelf life of pecans was described. The full-oil and supercritical carbon dioxide extracted (22% and 27% reduced-oil) native pecan kernels packaged in standard air mixture (21% O2, 79% N2), stored for up to 37 weeks at 25 °C and 55% RH, were subjected to hexanal analysis, sensory analysis, and determination of lipid class changes, that occur as the pecans age. Hexanal concentration of reduced-oil pecans was negligible throughout the storage, while full-oil pecans reached excessive levels by 22 weeks. Hexanal analysis was in agreement with the sensory scores. Free fatty acid lipid class was selectively extracted during the partial oil extraction process. Reduction in free fatty acids, and an overall reduction in lipid content on a per kernel basis, decreased the sites for oxidative deterioration and contributed to enhanced shelf-life of pecans. Work was supported by OCAST grant AR4-044 and the Oklahoma Agricultural Experiment Station.
An Alternative and Inexpensive Assay for Plant Invertases
Authors: Huang Y.H. , Picha David H. , Johnson Charles E.
Published: October 2019

The glucose-6-phosphate dehydrogenase (G-6-PDH) and glucose oxidase methods are commonly adapted for plant invertase assay. A disadvantage of the G-6-PDH assay is the relatively high cost of the coupling enzymes and cofactors. A disadvantage of the glucose oxidase method, which uses a glucose kit (Sigma, 510-A), is the presence of high activities of acid invertase and alkaline invertase in the PGO enzyme formula (peroxidase and glucose oxidase), which gives a falsely high invertase activity value. An alternative and inexpensive coupled assay was developed for enzymatic assay of plant invertases. In this assay, ADP produced from phosphorylation of glucose and fructose (hydrolysis products of invertases) is coupled to oxidation of NADH by the enzymes pyruvate kinase and lactate dehydrogenase in presence of phosphoenolpyruvate and NADH. This method was compared with the glucose-6-phosphate dehydrogenase method by using protein preparations derived from plant materials of three different species. Statistical analysis indicated that the alternative assay was similar in accuracy to the glucose-6-phosphate dehydrogenase method, with an advantage of reducing the cost from $0.85 to $0.35 per assay.