bluuebunny/crossref_metadata_2025 huggingface dataset:
Volatile Compounds for Control of Botrytis on Strawberry: Duration of Treatment and Use of Polymer Film
Authors: Archbold D.D. , Hamilton-Kemp T.R. , Barth M.M. , Langlois B.E.
Published: February 2019

A number of natural volatile compounds exhibit promise as postharvest fumigants for control of Botrytis on strawberry fruit. Because some of compounds may cause apparent phytotoxic responses by the fruit, short duration treatment is desirable. The compounds have been evaluated in single fruit bioassays with passively established modified atmospheres using a polymer film. The compound source was removed after 3 hours, 1, 3, or 7 days, or remained in the containers for the 10 day duration of the study. At levels which inhibited Botrytis in closed containers without film, E-2-hexenal was effective with a 1-day treatment, diethyl acetal was increasingly effective as treatment period increased, and 2-nonanone and methyl salicylate were not effective with continuous treatment. The levels of both the source compound and its metabolites were different using the film than without it. The film, used to allow gas diffusion and exchange with the surrounding environment, may allow diffusion of the volatile compounds and their metabolites. Thus, successful use of the compounds in modified atmosphere storage may require knowledge of their diffusion through the films to establish the appropriate levels for effective fumigation of the fruit and avoid adverse quality effects.
Applied Research for Citrus and Tropical Fruit Ingredient and Raw Materials Development for Juice Processing
Authors: Smith-Kayode O. , Babalola A. , Agbeja V.O. , Fasesan S.O.
Published: February 2019

The National Horticultural Research Institute coordinates many projects designed to boost and improve the use of various fruits and vegetables around Nigeria. To achieve the set goals for fruit processing, projects are undertaken in cooperation with selected laboratories. Based on the depth of work required for transforming research results into patented products, university and industry were involved in a collaborative assignment in sweet orange concentrate research and development. The work covered engineering and product testing, packaging, and sensory experiments in which materials and resources were shared at the participating center. This presentation focuses on guidelines for overcoming the problems associated with collaborative studies in developing countries and suggestions on funding components.
Chilling Stress Protection in Cucumber: A Role for Antioxidants?
Authors: French David A. , Parkin Kirk L.
Published: February 2019

To examine the role of endogenous antioxidants in providing chilling stress protection, field-grown cucumber (Cucumis sativus L. cv. Eureka) fruit were stored in the dark and evaluated throughout storage. Storage treatments included continuous chilling (C) (5°C), continuous tempering (T) (12°C), intermittent warming (IW) (1 day at 12°C every 4 days) for 1, 2, 3, or 4 cycles, and preconditioning (PC) (12°C for 4 or 8 days) before chilling. Fruit exposed to in-field chilling (FC) were also stored under continuous chilling at 5°C. Samples were evaluated visually for tissue damage (lack of exudate, water-soaked appearance), and ascorbic acid (Asc) and reduced (GSH) and oxidized (GSSG) glutathione levels and glutathione reductase (GtR) and ascorbate free radical reductase (AFRR) activities were determined. Each 4 days of PC extended storage life by 7 days relative to C. FC or 1–2 IW cycles also extended storage life relative to C. With all treatments, Asc depletion preceded visual tissue damage, whereas GSH, GtR, and AFRR were not depleted before such damage. GSSG levels remained low throughout storage. GtR activity was elevated by FC and IW. AFRR activity was elevated by all treatments. Asc levels were elevated initially by all treatments, with this elevation lasting longer with PC and T. These results suggest that Asc levels decline during stress in the absence of an obvious lesion in the Asc regeneration scheme.
Temperature Response of Fragaria Species
Authors: Archbold Douglas D.
Published: February 2019

Plants of a diverse collection of Fragaria clones from a range of native habitats representing F. chiloensis, F. virginiana, F. virginiana glauca, and F. vesca, were grown in a controlled environment at one of three day/night temperatures, 15/15, 23/15, or 31/15°C. Relative growth rate (RGR) and net assimilation rate (NAR) were estimated from plant leaf areas and total dry weights. At 23/15°C, the species mean RGR and NAR values were comparable although clones within species exhibited significant variation. At 15/15 and 31/15°C, RGR and NAR for species were lower than at 23/15°C. At 31/15°C, chiloensis and vesca mean values were reduced more than the others, to less than 50% the 23/15°C values. Also, NAR declined most for chiloensis, to 45% the 23/15°C value. At 15/15°C, virginiana had much higher RGR and NAR values than the other species, and its NAR mean value was greater than at 23/15°C. Although the species means would suggest that there are interspecific differences in temperature response, intraspecific variability was also large. Thus, classifying Fragaria species by temperature response may be an over-generalization.
Desiccation Tolerance of Dormant Grape Buds from Germplasm Accessions in the Cold-Hardy Vitis Core Subset Collection
Authors: Forsline Philip L. , Lamboy Warren F. , McFerson James R. , Stushnoff Cecil
Published: February 2019

The USDA–ARS germplasm collection of cold-hardy Vitis held at the Plant Genetic Resources Unit, Geneva, N.Y., has over 1300 clonal accessions maintained as field-grown vines. Security back-up using field-grown or potted vines at remote sites or via in vitro methods is costly. Cryopreservation offers a safe, cost-effective alternative. While we routinely employ cryogenic storage of dormant buds of Malus, dormant buds of Vitis generally do not appear to tolerate the desiccation levels required by our current cryopreservation protocol. Since tolerance to desiccation and cold appear to be correlated in Vitis, we tested desiccation tolerance of 60 germplasm accessions selected from the core subset to represent a range of cold hardiness. Budwood was collected in December 1995 in Geneva, stored at –4°C in sealed bags, and systematically desiccated to 30% and 20% moisture. In some treatments, additional desiccation was imposed by slow freezing to –25°C. Microscopic examination of rehydrated buds indicated 60% of accessions tolerated desiccation as low as 20% moisture. Freeze-desiccation at –25°C after desiccation at –4°C neither increased nor decreased viability in these accessions. Only slight modification so current protocols should be necessary for cryopreservation of this class. Of the remaining accessions, 25% tolerated desiccation to 30% moisture, but 15% were intolerant to any desiccation level tested. Techniques must be developed to successfully cryopreserve both these classes of accessions.
Seasonal Fluctuations in Cold Hardiness and Protein Profiles of Five Rhododendron Cultivars
Authors: Lim C.C. , Arora R.
Published: February 2019

A time-course study was conducted to characterize seasonal patterns of cold hardiness (CH) and protein profiles in the leaf tissue of five Rhododendron cultivars (`Grumpy Yellow', `Vulcan's Flame', `Autumn Gold', `Chionoides', and `Roseum Elegans'). Leaf samples were collected monthly (starting in mid September) and leaf discs were subjected to controlled freezing and thawing regimes. CH (LT50 defined as temperature causing 50% injury) was assessed by electrolyte leakage and visual observations. Data indicate that cultivars varied in their CH in nonacclimated state and in their ability to cold acclimate. Results obtained in September showed `Grumpy Yellow' to be least hardy (about –3°C) and `Roseum Elegans' to be most hardy (about –7°C). All cultivars exhibited successive increases in CH during fall and winter. Maximum CH in all cultivars occurred by December/January with `Chionoides' being most hardy (about –31°C) while `Grumpy Yellow' was least hardy (about –20°C). LT50 based on electrolyte leakage was highly correlated with visual rating. Seasonal changes of protein profiles and relationship of specific stress proteins to cultivars' CH and cold acclimation ability are discussed.
Gas Exchange and Vine Water Relations are Crop Load Dependent
Authors: Naor A. , Gal Y. , Bravdo B.
Published: February 2019

The effect of shoot density and crop level on gas exchange and water relations of filed-grown Sauvignon blanc was studied. Ten and 44 shoots/vine and one and two clusters per shoot treatments were examined in a factorial design. The two-cluster treatments had higher stem water potential (Ystem), assimilation rate, and stomatal (gs) and nonstomatal (gm) conductance. A quantitative analysis suggests that capacitance cannot account for the simultaneous increase in gs and Ystem in the two clusters treatment. The two-cluster treatment had higher Ystem for similar transpiration rates (similar gs) compared to the one-cluster treatment. The similar transpiration rate and lower stem to root water potential difference in the two-cluster treatment was explained by increased root permeability in the two-cluster treatment. The similar gs–gm, in spite of a meaningful decrease of gs with decreasing Ystem, suggests that gs and gm synchronize themselves to perturbations of gm due to sink effect and gs due to water stress.
Foliar Dehydration Tolerance of Twelve Deciduous Tree Species
Authors: Augé Robert M. , Duan Xiangrong , Croker Jennifer L. , Green Craig D. , Witte Will T.
Published: February 2019

We compared the potential for foliar dehydration tolerance and maximum capacity for osmotic adjustment in twelve temperate, deciduous tree species, under standardized soil and atmospheric conditions. Dehydration tolerance was operationally defined as lethal leaf water potential (Ψ): the Ψ of the last remaining leaves surviving a continuous, lethal soil drying episode. Nyssa sylvatica and Liriodendron tulipifera were most sensitive to dehydration, having lethal leaf Ψ of –2.04 and –2.38 MPa, respectively. Chionanthus virginiana, Quercus prinus, Acer saccharum, and Quercus acutissima withstood the most dehydration, with leaves not dying until leaf psi dropped to –5.63 MPa or below. Lethal leaf Ψ (in MPa) of other, intermediate species were: Quercus rubra (–3.34), Oxydendrum arboreum (–3.98), Halesia carolina (–4.11), Acer rubrum (–4.43), Quercus alba (–4.60), and Cornus florida (–4.88). Decreasing lethal leaf Ψ was significantly correlated with increasing capacity for osmotic adjustment. Chionanthus virginiana and Q. acutissima showed the most osmotic adjustment during the lethal soil drying episode, with osmotic potential at full turgor declining by 1.73 and 1.44 MPa, respectively. Other species having declines in osmotic potential at full turgor exceeding 0.50 MPa were Q. prinus (0.89), A. saccharum (0.71), Q. alba (0.68), H. carolina (0.67), Q. rubra (0.60), and C. florida (0.52). Lethal leaf Ψ was loosely correlated with lethal soil water contents and not correlated with lethal leaf relative water content.
Agro-ecological Variation in the Growth and Development of Grain Amaranth (Amaranthus sp.) in Nigeria
Authors: Olufolaji A.O. , Denton Lanre A.
Published: February 2019

The pale yellow-seeded Amaranth is virtually a new crop in Nigerian agriculture. Under the sponsorship of the National Agricultural Research Project (NARP), 12 accessions were evaluated for agronomic characters and yield attributes in three agro-ecological zones of the country. The results showed significant variation in the agronomic characters of the accessions. Top accessions recorded average grain yields of 4.5, 3.5, and 2.6 t·ha–1 in Sudan savanna, derived savanna, and guinea savanna zones of the country, respectively. Response of the accessions to qualitative and quantitative characters in the zones are discussed.
What Do Master Gardeners Do?
Authors: Ruppert Kathleen C.
Published: February 2019

The Master Gardener Program in Florida began in 1979 with the three pilot counties of Brevard, Dade and Manatee. Today, 48 of the state's 67 counties manage this volunteer program. Data will be reported as to how many volunteers have been trained and the hours they volunteered each year, along with the percentage of time agents or program assistants estimate they devoted to the program each year since 1989. The activities of the volunteers for each year will also be depicted. These indicate a change in need by county agents over the years for the services of their volunteers.
Painted Containers: A New Method for Imidacloprid Application
Authors: Pasian Claudio C. , Struve Daniel K. , Lindquist Richard
Published: February 2019

The effectiveness of two methods of application of the insecticide imidacloprid in controlling 1) aphids (Brachycaudus helichrysi) on Chrysanthemum plants, Dendranthema ×grandiflora (Ramat) (cv. Nob Hill) and 2) whitefly (Bemisia argentifolii) on poinsettia, Euphorbia pulcherrima (Wild.) (cv. Freedom Red) were compared. Plants were grown in containers with their interior covered by a mixture of flat latex paint and several concentrations of imidacloprid (0, 10, 21, 42, and 88 mg·L–1), or treated with a granular application of the insecticide (1% a.i.) according to label recommendations. All imidacloprid treatments were effective in reducing aphid survival after 8 weeks. The two most effective treatments were: granular (1% a.i.) and 88 mg·L–1 with an average of 0.2 aphid per plant as opposed to 50.4 aphids per plant for the control. The 42-mg·L–1 treatment had an aphid survival rate 1.6 aphids per plant. All imidacloprid treatments were effective in reducing white fly larvae. The 42 and 88 mg·L–1 and the granular (1% a.i.) were equally effective in reducing larvae numbers in lower poinsettia leaves: 0.5, 1.9, 0.9 larvae/2.5 cm leaf disk, respectively, while the control treatment had 62.9. None of the plants given treatments with paint showed any sign of phytotoxicity. These results suggest the possibility of a new application method for systemic chemicals with the potential of reducing or eliminating Worker Protection Standard (WPS) Restricted Entry Intervals (REI) and reducing the release of chemicals to the environment. Chemical name used: 1-[(6-Chloro-3-pyrimidil)]-N-nitro-2-imidazolidinimine.
Effect of Humic Acid on Growth of `Muskogee' Crape Myrtle after Container Shielding Treatments
Authors: Schluckebrier John G. , Martin Chris A.
Published: February 2019

Rooted cuttings of crepe myrtle (Lagerstroemia indica L. × L. fauriei `Muskogee') were transplanted into 3.8-L black polyethylene containers filled with a bark-based rooting substrate and exposed for 2 months during Summer 1995 to either of three container shielding treatments: containers shielded from insolation (container shielded inside a whitewashed 11.4-L black polyethylene container), containers exposed to insolation, or containers shielded for 1 month then exposed for 1 month. Mean highest temperature in the western quadrant of rooting substrate of exposed containers was 16°C higher than for those in shielded containers. Containers exposed for 2 months had reduced root and shoot growth and increased leaf N compared with the other two treatments. Crape myrtle plants were next transplanted into 27.0-L polybags, transferred into a temperature-controlled glasshouse, and fertigated to container capacity every 3 days with humic acid extract at concentrations of 0, 50, 150, or 300 μl·L–1 for 2 additional months. Effects of the container shielding treatments for all growth parameters remained evident until the end of the experiment. Shoot and root extension growth of plants previously in containers shielded for 2 months and containers exposed for 2 months, responded in a quadratic fashion to humic acid extract concentration levels.
Direct Potting of Ornamental Grasses using Two Division Sizes
Authors: Brand Mark H.
Published: February 2019

Nursery production of many ornamental grasses involves potting of established liners into 8.5-L containers. Direct potting of bare root divisions into 8.5-L containers may represent a more efficient production method. Large and small divisions (based on number of tillers and volume) of eight ornamental grasses were potted directly into 8.5-L containers. The potting medium used was a 3 aged pine bark: 2 peat moss: 1 sand nursery mix (by volume), amended with dolomitic lime at 3 kg/yard3, and top dressed with Sierra 17-6-10 plus minors at 40 g/container, 8 to 9 month fertilizer. Plants were grown outdoors in a container nursery from May through September. All grasses tested performed well using the direct potting method, with 100% survival. Large divisions of Miscanthus sinensis cultivars produced plants with greater fresh weight, dry weight and number of tillers than did small divisions. Division size did not affect Miscanthus foliage or flower height but did affect number of flowers for `Graziella' and `Purpurascens'. Large divisions of Calamagrostis `Karl Foerster', a grass grown primarily for flowering, produced twice as many flowers as small divisions. Panicum virgatum and Pennisetum alopecuriodes showed signs of nutrient stress when grown from large divisions. Although a greater number of tillers was produced by large divisions of Panicum and Pennisetum, fresh weight, dry weight, flower height, and foliage height were similar to or less than that observed on plants from small divisions.
Controlled-release Fertilizer Rate Influences Plant Growth, Flowering, and Tillering of Pennisetum alopecuroides
Authors: Brand Mark H.
Published: February 2019

Information on fertility optimization for container-grown ornamental grasses is limited. For ornamental grasses, growers are concerned with the degree of flowering, number of tillers, and height and width of the plants as well as other growth or ornamental components. Pennisetum alopecuroides divisions potted into 8.5-L containers were grown outdoors in a container nursery from May through September. The potting medium used was a 3 aged pine bark: 2 peatmoss: 1 sand nursery mix (by volume), amended with dolomitic lime 3 kg/yard3. Sierra 17-6-10 plus minors, 8 to 9 month controlled-release fertilizer (CRF) was top dressed at 20, 30, 40, 50, or 60 g/container. Foliage height increased linearly with increasing CRF rate. Flower height increased to a maximum at 40 g of CRF per container and then decreased with higher levels of CRF. Basal plant width exhibited a quadratic response to CRF rate, reaching a maximum at 40 g of CRF per container. The greatest number of flowers and tillers were obtained using 50 g of CRF per container. Maximizing the number of flowers is important for marketing of Pennisetum, since this plant is grown primarily for its flowering.
Field Performance of Wildpeach (Prunus persica L.) as a Rootstock for Peach Compared with Lovell and Nemaguard
Authors: Yadava U.L.
Published: February 2019

A planting of 48 trees of `Redhaven' scion on Lovell, Nemaguard, and Wildpeach rootstocks (RS) was established in 1990, with four replications in randomized complete-block design. Cultural practices common in Georgia were used to maintain the planting. Orchard performance for peach tree short life (PTSL) related tree survival, RS suckering, fungal gummosis, and tree stresses from cold injury and Pseudomonas canker, was investigated to examine RS potential of Wildpeach compared with Lovell and Nemaguard. Trees on all RS showed 100% survival for the first 5 years in the orchard. Although canker became more prevalent in later years, trees had significantly higher ratings on Nemaguard (2.88) and Lovell (2.50) RS than on Wildpeach (1.44). However, PTSL stress enraged by Pseudomonas killed one tree each on Lovell and Wildpeach RS during 1995. Trunk cambial browning that estimated cold injury was trivial due to mild winters; however, trees on Nemaguard had higher TCB ratings (1.25) than on other RS. Trees on Wildpeach had fewer suckers than on Nemaguard or Lovell. Gummosis ratings were higher on Nemaguard RS than on Lovell and Wildpeach. The results showed that Wildpeach has good potential for a peach RS.
Influence of Training Systems on Tree Size, Yield, and Fruit Quality of 15 Peach Cultivars
Authors: Crassweller R.M. , Smith D.E.
Published: February 2019

A peach and nectarine cultivar and training trial was planted in 1989. Training methods were open center (OC) and central leader (CL). The orchard was divided into three sections for early, mid-, and late season peaches with 10 individual-tree replications. The following characteristics were measured from 1989 to 1994: trunk cross sectional area, fruit yield, number of fruit, and fruit color. Early season peaches, those ripening with and before `Salem' in the OC system had significantly greater TCSA at the end of the fifth growing season. At the end of the sixth growing season, however, there was a significant training cultivar interaction. There were no differences between the mid- or late season cultivars. Measurable yields were obtained in 1991 through 1993. In all years, greater yields per tree were observed from trees in the CL system, although not significantly different for the late season cultivars. `Redhaven' and `Newhaven' had the highest yields for the early season cultivars, `Glohaven' for the mid-season cultivars, and `Cresthaven' and Biscoe for the late season cultivars. Trees in the CL system tended to have higher tree efficiency than trees in the OC system. Fruit color at harvest varied by year and training system.
Relationship of Nitrogen and Plant Populations to Yield and Stem Diameter in Broccoli
Authors: Sterrett S.B. , Savage C.P.
Published: February 2019

Commercial production of bunched broccoli on the Eastern Shore of Virginia has been limited because of shortened internodes resulting in thick, tough stalks. A field study was completed to examine the influence of plant type (transplants or direct seeded), plant population (5800 or 8700 plants/ha), and N application (112 kg/N with zero, one, or two sidedress applications of 40 kg·ha–1) on marketable yield, head diameter, and stem diameter of `Packman' broccoli. None of the measured characteristics improved significantly with sidedress N application. Marketable yield and average head weight were significantly correlated (P = 0.01) to the total number of heads harvested (r = 0.70 and r = –0.91, respectively). More heads were harvested for the high population, direct-seeded treatment and fewer for the low-population transplants. Average stem diameter of transplants was slightly greater than that of direct-seeded broccoli being significant (P = 0.05) in the second and third harvests. However, few stems were of commercially acceptable diameter regardless of treatment combination. Additional evaluation of cultural management strategies and cultivar selection is needed to successfully promote commercial production of bunched broccoli in this growing area.
Estimating Amount of Watering of Greenhouse-grown Muskmelons
Authors: Nakamura Tetsuya
Published: February 2019

In greenhouse-grown muskmelon (Cucumis melo L.) cultivation at Shizuoka Prefecture, Japan, growth, fruit enlargement, and translocation rates must be controlled by water content of plants through environment control. To produce high-quality muskmelons, growers have to control soil moisture appropriately through daily watering, but it has been difficult to estimate the suitable amount of water. Our study was performed to estimate watering using simple watering model. It is well known that evaporation and transpiration rates are in proportion to the differences between water vapor density of atmosphere and that of leaf and soil, respectively, and are inversely related to their resistances. Therefore, an amount of water to be watered was estimated from air temperature, soil temperature, relative humidity, solar radiation, and grower's experience. The evaporation and transpiration resistances were set up to make evapotranspiration close to amount of watering. First, to estimate amount of irrigation, the relationship between the grower's imaginary watering, which ignored neither yesterday's watering nor today's soil moisture, and today's weather index, which indicate today's evapotranspiration rate, was investigated. Secondly, the yesterday's estimated evapotranspiration and yesterday's amount of evapotranspiration rate were compared. From the comparison, soil moisture conditions before watering whether soil is wet or dry were estimated. Third, revised coefficient of watering was decided by grower. Finally, estimated amount of watering was obtained from the following things; today's weather index, comparison of the prediction and actual evapotranspiration, revised coefficient. As the result, anybody who had no special knowledge could manage the soil moisture by only observing today's weather like skilled growers.
Estimation and Significance of Nutrient and Starch Storage Pools in Mature, Alternate-Bearing Pistachio (Pistacia vera. L.) Trees
Authors: Rosecrance Richard C. , Weinbaum Steven A. , Brown Patrick H.
Published: February 2019

The effect of crop load on nutrient and starch storage in mature, alternate-bearing pistachio trees was examined. Tree storage pools were estimated from the differences in nutrient and starch contents of perennial tree parts between dormancy (the period of highest nutrient and starch content) and following spring flush (the period of lowest nutrient and starch content). Following a lightly cropping (off) year, trees contained significantly larger N, P, and K storage pools than following a heavily cropping (on) year. The relative contribution of leaf nutrient resorption to tree nutrient storage pools varied depending on the crop load. Nutrient storage is a function of net leaf nutrient resorption and current uptake from the soil. Leaf nutrient (N, P, and K) resorption was a more significant component of nutrient storage in on-year than off-year trees. The contribution of nutrient storage to shoot (i.e., leaves, fruit, current-year wood) nutrient contents was evaluated following the spring flush (May) and nut fill (September) periods. Nutrient storage pools are an important source of nutrients during the spring flush of growth, but nutrient demands during nut fill are met primarily by current nutrient uptake from the soil. The relationships between nutrient storage and uptake are discussed.
Behavior of Red Roomy Grapevines to Cycocel and Some Micro Nutrients: II. The Effect on Nutritional Status of the Vines, Berry Set, and Yield
Authors: Akl A.M. , Faissal F. Ahmed , William S. Youssef
Published: February 2019

Nutritional status of the vines, berry set, and yield as effected by the application of cycocel at 0.0, 500, 1000, or 1500 ppm and/or using a mixture of Mn, Zn, Cu, and Fe at 0.3% were studied. Cycocel was applied at different periods starting immediately after pruning and ending at 30 days after berry set. Results showed that three sprays of cycocel immediately after pruning, 15 days before first bloom, and at 30 days after berry set, particularly with the application of the four micronutrients together at 0.3%, proved much more effective in increasing the leaf content of total carbohydrates, total N, Zn, Mn, Cu, and Fe as well as berry set, number of clusters, yield and average cluster weight. Spraying Red Roomy vines three times with cycocel at 1000 ppm in combined with Mn + Zn + Cu + Fe at 0.3% gave satisfactory improvement in nutritional status and yield.
Effect of Plastic Mulch, Floating Rowcovers, and Microtunnels on Insect Populations and Yield of Muskmelon
Authors: Farias-Larios J. , Orozco M. , Guzman S. , Perez J.
Published: February 2019

This work was conducted for evaluate the influence of clear and black polyethylene mulches, used alone or combined with floating rowcover (FRC) and plastic perforated microtunnels, on insect populations, growth and yield of muskmelon. Treatments evaluated were 1) clear plastic + FRC, 2) polyethylene perforated microtunnel, 3) clear plastic + polyethylene not perforated microtunnel, 4) black plastic + FRC, 5) clear plastic, 6) black polyethylene, 7) clear plastic + oil, and 8) bare soil. Aphids and sweetpotato whitefly adults and nymphs were completely excluded by floating rowcovers while the plots covered. The export and national quality fruit yield was major in the mulched beds in relation to control. Clear polyethylene mulch + FRC increased number of fruit and export marketable fruit of cantaloupe (45.2% and 44.8%) with respect to black plastic + FRC, respectively. It is proposed that, under tropical conditions and under high insect stress, mulches combined with floating rowcovers should be selected for their effects on insects in addition to their effects on melon yield. Polyethylene microtunnels were found not economical for cantaloupe production in western Mexico.
Evaluation of Sesquiterpene Carboxylic Acids as a Mechanism for Resistance to the Tomato Pests Helicoverpa zea (Boddie) and Spodoptera exigua (Hubner).
Authors: Frelichowski James E. , Juvik John A.
Published: February 2019

Sesquiterpene carboxylic acids (SCA) are synthesized by leaf trichomes of a wild tomato species Lycopersicon hirsutum accession LA 1777 and confer resistance to the tomato pests Helicoverpa zea (Boddie) and Spodoptera exigua (Hubner). Larvae of both species exhibited a reduction in survival and growth rate with altered feeding behavior when exposed to SCA in choice and no-choice insect bioassays. Larvae of both species were reared on artificial insect diets with SCA added at 0, 10 and 60 mg SCA per g of diet. All larvae perished in the 60 mg·g–1 treatment which is comparable to the levels of SCA found on LA 1777. H. zea and S. exigua showed about 35% and 60% reduction in survival to adult and 38% to 22% increase in life cycle duration, respectively, in the 10 mg·g–1 treatment relative to the control. Similar reductions in growth rate and survival were observed when larvae were reared on leaves coated with SCA. Choice bioassays with control (0 mg SCA/g leaf) and 60 mg SCA/g treated leaf tissue demonstrated 2.3-fold increase in larval avoidance and 50% reduction in feeding on treated leaves. Our results suggest that breeding for SCA synthesis in tomato would produce lines with increased resistance to the tomato pests H. zea and S. exigua. Backcross breeding procedures using LA 1777 have initiated the introgression of the SCA genes into cultivated tomato germplasm. Studies of inheritance of genes coding for SCA synthesis are underway to reveal allelic interactions and facilitate there introgression into the cultivated tomato germplasm.
Effects of Nutrient and Growth Regulator Treatments on the Growth and Development of Marigolds
Authors: Clardy Arvazena E. , Garton Stephen
Published: February 2019

Two cultivars of Tagetes erecta Marigolds—Hero Yellow and Safari Tangerine—were grown hydroponically in two different nutrient solutions. The experiment was implemented in the greenhouses on the campus of Alabama A&M Univ., from March to May 1995. The experiment was to assess the effects of growth and development of Marigolds. Heights of seedlings, germinated in grodan (rockwool) cubes were measured and placed randomly in the hydroponic units. Plants were drenched with five rates of either Paclobutrazol (Bonzi) and Uniconazole (Sumagic). The experiment was laid out as a randomized complete block design with either three or four replications of the treatment, which were factorial combinations of variables. After 75 days measurements were made of plants heights, flower bud numbers and dry weights of shoot and root systems. Shoot dry weights were affected by growth regulator treatments, variety, nutrient treatments and a combination of variety and nutrient treatments. Root dry weights were affected by nutrient treatments. Flower bud formation and numbers were affected by the combination of nutrient and variety. Heights were affected by growth regulator treatments, variety and nutrient treatments.
Behavior of Red Roomy Grapevines to Cycocel and Some Micronutrients: I. The Effect of Buds Behavior and Growth
Authors: Akl A.M , Faissal Ahmed F. , William S. Youssef
Published: February 2019

Our objectives were to investigate the effect of spraying cycocel at effect of spraying cycocel at 0.0, 500, 1000, or 500 ppm starting immediately after pruning and ending at 30 days after berry set and/or the application of a mixture containing Mn, Zn, Cu, and Fe at 0.3 per each element. Data on buds behavior end growth characteristics (i.e., number of internodes and laterals, leaf area, cane thickness, and weight of pruning) were tabulated. Results showed that three sprays of 1000 ppm cycocel immediately after pruning, 15 days before first bloom, and at 30 days after berry set combined with using the micronutrients together at 0.3% substantially raised burst and fruiting buds and all the studied characteristics, while reducing dormant and vegetative buds. Three sprays of 1000 ppm cycocel plus 0.3% of a mixture containing the four micronutrients caused a positive influence on the behavior of buds and growth aspects of Red Roomy vines.
Effect of Mycorrhizal Fungi and Phosphorus Stress on Gas Exchange, Growth, and Development of Capsicum annuum L. cv. San Luis (Chile Ancho pepper)
Authors: Aguilera L. , Davies F.T. , Olalde-Portugal V. , Duray S.A. , Phavaphutanon L.
Published: February 2019

Seedlings of Capsicum annuum L. cv. San Luis were grown in pots containing a pasteurized mixture of sand and sandy loam soil inoculated or noninoculated with the V-A mycorrhizal (VAM) fungus Glomus intraradices Schenck et Smith. Long Ashton nutrient solution (LANS) was modified to supply P at 0, 11 or 44 μg·ml–1. Diurnal gas exchange measurements were taken 15, 30 and 50 days after the experiment was initiated. Plant growth, leaf elemental content, and mycorrhizal development were assessed 52 days after transplanting. Gas exchange and net photosynthesis were enhanced by mycorrhiza and full strength LANS fertilization (44 μg·ml–1). The symbiosis increased leaf nutrient content of P, K, Mg, S, Fe, Mn, Zn, Cu, B, Mo, and Al. Mycorrhizal plants had higher shoot dry weights, leaf number, leaf area, and fruit primordia than nonmycorrhizal plants with P at 0 and 11 μg·ml–1. Root colonization (arbuscules, vesicles, and internal and extraradical hyphae development) were higher with P at 0 and 11 μg·ml–1. The quantity of spores recovered in soil was independent of P treatments.
Comparison of Root Death in Common Bean (Phaseolus vulgaris) grown in Sand Culture and Field Conditions
Authors: Fisher Maria , Eissenstat David , Lynch Jonathan
Published: February 2019

In annual plant species, root death has been assumed to be closely correlated with shoot senescence. However, in a preliminary study with common bean grown in sand culture beyond physiological maturity (114 days), no root death occurred. We investigated whether the incidence of bean root death was higher under field conditions than in sand culture. Root death was defined as root disappearance. The sand culture consisted of silica sand and P-loaded alumina. Plants in this system were fertigated twice daily with complete nutrients supplied in adequate amounts. The field planting was on a Hagerstown silt loam in central Pennsylvania. Roots were observed using minirhizotrons every 1 to 3 weeks after planting. In sand culture, incidence of root death was monitored on a population of 170 roots from three plants between 25 and 88 days (shoot senescence) after planting Root death was 10%. In the field study, 55% of the 53 roots examined died between 32 and 93 days (shoot senescence) after planting. Biological factors present in the field and not present in sand culture appeared to contribute to root death. The persistence of roots in sand culture suggests a lack of programmed root senescence in contrast to shoot senescence. This has interesting implications for resource allocation during reproduction and in face of belowground herbivores and pathogens.
“Green” Water Treatment for the Green Industries: Opportunities for Biofiltration of Greenhouse and Nursery Irrigation Water and Runoff with Constructed Wetlands
Authors: Berghage R.D.
Published: February 2019

Constructed wetland biofilters have been widely used in recent years to provide secondary or tertiary water treatment, effectively reducing BOD, TSS, nitrate and ammonium, and some organic pollutants from municipal, industrial, and agricultural waste sources. The greenhouse and nursery industries, like all agricultural enterprises, have found themselves under increasing pressure to reduce or eliminate discharge of contaminated wastewater. In response, many greenhouse and nursery operators have installed, and are using, a variety of runoff containment and recirculating irrigation systems. While effective in reducing or eliminating wastewater discharge, these systems can become contaminated themselves and require treatment of the water before it can be reused in the irrigation system. Further, if the water should become contaminated and unusable, environmental discharge of this spent water from a recirculating irrigation system is perhaps even more problematic than simply allowing the excess irrigation water to be dumped in the first place. Potential contaminants in a recirculating irrigation system could include pesticide and other organic residues, excess fertilizer and non-fertilizer salts, and plant pathogens. The primary concern in greenhouse and nursery discharge wastewater is usually fertilizer salts, although pesticide and other organic chemical residues may also be of concern. Biological filtration using constructed wetlands may be a simple low-cost method for greenhouses and nurseries to treat these contaminants.
Determining Fruit Maturity in Research and Industry Applications
Authors: Beaudry Randolph M. , Blankenship Sylvia M.
Published: February 2019

The reasons for knowing the maturity of fruit center around controlling fruit quality after harvest. Farmers are usually concerned with trying to determine harvest date to fit their labor, storage, and marketing needs, whereas research scientists are typically trying to account for the effects of maturity as a variable in experiments. Specific goals for farmer and researcher will, in part, govern what maturity indices are used and what values are acceptable. Restrictions in time and equipment will also affect choice of maturity assessment methods. In some instances, internal or external characteristics might be more important. Because changes in a number of characteristics comprise ripening, there is no single criteria or method that can be termed “best.” However, for each situation, an optimal choice of criteria or method may exist. The logic and information necessary to reach those optimal choices, from the perspective of the researcher and the commercial horticulture operation, is presented and contrasted.
Health Functionality of Blueberries
Authors: Kalt W.
Published: February 2019

Fruit extract of the European blueberry, or bilberry (Vaccinium myrtillus), is a major component of a great number of pharmaceutical and food supplement products. Compared to most small fruits, bilberry has a high concentration of anthocyanin pigments. Anthocyanins are of biomedical interest due to their properties as antioxidants and protein cross linkers. The major clinical applications for anthocyanins are in ophthalmology, blood vessel and connective tissue disorders, and diabetes. Bilberries are harvested from wild stands throughout Scandinavia, Eastern Europe, and at higher altitudes in southeastern France. Because they are wild, a wide array of genotypes make up the commercial product. As part of an investigation of the nutraceutical components of North American wild lowbush blueberries (Vaccinium angustifolium), we are comparing the anthocyanins and other phenolic components from fruit of commercially available Vaccinium species. We are particularly interested in the variation in composition among Vaccinium clones and species.
Development of Insect-tolerant Plants with Somaclonal Variation
Authors: Bridgen Mark
Published: February 2019

The potential value of somaclonal variation for economically important plants is well-documented. The process of somaclonal variation can arise from a controlled or a random source of variation. Variability can be obtained by applying cellular pressures and selection. Valuable resistance to diseases and nematodes has already been accomplished with somaclonal variation; now, plant tolerance to pests has been realized. Tetranychus urticae, the two-spotted spidermite, and Trialeurodes vaporariorum, the greenhouse whitefly, were disinfected and introduced to aseptic shoot cultures of Torenia fournieri. These pests were allowed to feed until such time that their populations decreased due to the absence of food. The plant cells that remained after feeding were induced to form adventitious shoots and plantlets. These regenerated plantlets were acclimated to greenhouse conditions and evaluated for tolerance to the pest to which they were subjected in vitro. Highly significant differences were found in somaclones for both the two-spotted spidermite and greenhouse whitefly when compared to control plants. A wide range of variability was observed among the somaclonal population. There were significantly fewer mite eggs laid on plants regenerated from in vitro cultures screened with two-spotted spidermites than on seed-sown controls. Regenerants from cultures screened with whiteflies in vitro had fewer eggs, immatures and live adults than controls. The potential for somaclonal variation to be used as a method to develop insect resistant plants will be discussed.
Nutritional Improvement of Horticultural Crops through Plant Breeding
Authors: Bliss Fredrick A.
Published: February 2019

Fruits and vegetables are rich sources of the micro mineral elements and vitamins often lacking in diets based on cereals, grain legumes, and starchy roots and tubers, but void of animal products. When embarking on a breeding program to improve nutritional compounds, the way the fruit or vegetable is consumed in mixed diets must be considered. To alleviate nutritional problems, the nutrients must not only be present in the plant parts consumed, but also absorbed efficiently in the body. In some cases, it may be necessary to modify compounds to improve absorption as well as increase the concentration. Breeding to improve nutritionally related traits can be approached in a manner similar to that for other traits; i.e., identification of genetic variability, selection for enhanced levels using either individual phenotype or family mean values, and testing for field performance. In addition to improving amount and availability, avoidance of undesirable correlated responses due to genetic or physiological linkages between the trait of interest and other traits deleterious to either plant growth or the consumer is critically important during selection. The growing number of molecular marker-based linkage maps should prove especially useful for identifying genes of interest and employing marker-aided selection. When insufficient variability for amount or type of compound is present in the gene pool, strategies using transgenic plants may be useful.
Changes in Nutritional Value of Horticultural Food Crops Affected by Handling, Storage, and Processing
Authors: Buescher Ron
Published: February 2019

Postharvest handling, storage, and processing greatly affect retention and bioavailability of nutrients in horticultural food crops. Although there are a few exceptions, concentrations of most nutrients are reduced by all postharvest operations. Losses of certain nutrients may range from 5% to 100%, depending on their chemical stability, solubility, and postharvest treatment. Therefore, the amount of a particular nutrient in a horticultural food at the time of harvest may not reflect the amount present when the raw or cooked food is consumed. Most vitamins are susceptible to oxidation catalyzed by enzymes, light, pro-oxidant metals, and active oxygen species. Also, nutrient retention and stability are affected by heat, leaching, and certain preservatives, such as sulfites. Physical injuries during handling, processing, and preparation for consumption accelerate vitamin degradation. Therefore, nutrient losses may be very large in minimally processed and food service products that are marketed in peeled, sliced, or shredded forms. Other processing methods, such as dehydration, fermentation, freezing, and canning usually result in significant losses in nutrient concentrations. Although processing generally contributes to loss of nutrient content of foods, certain processing methods improve the bioavailability of some minerals and vitamins, which may increase the actual nutritional value of the food. Methods to reduce inhibitors and antagonists of nutrient availability should receive major emphasis in efforts to improve nutritional value, along with efforts to improve the amount and retention of nutrients in horticultural food crops.
Use of Compost Products for Ornamental Crop Production: Research and Grower Experiences
Authors: Fitzpatrick George E. , Duke Edwin R. , Klock Kimberly A.
Published: February 2019

Horticultural growing medium components must be selected with regard to their influence on properties such as cost, availability, ease of mixing, appearance, pH, nutrient levels, soluble salt levels, exchange capacity, aeration, particle size distribution, bulk density, water-holding capacity, and consistency. Over the past several decades, various types of compost products made from urban waste materials have been evaluated as components in horticultural growing mixes. The highest-quality compost products tested have frequently compared favorably with peat as one of the organic components in growing mixes. The lowest-quality compost materials tested have retarded plant growth and, in extreme cases, contributed to plant mortality. Occasionally, compost products that performed well in research trials did not prove to be satisfactory when used in commercial nursery crop production because of the lack of repeatable consistency between batches produced in large-scale municipal composting operations. One of the major reasons for the lack of consistency in compost quality is the highly variable nature of organic feedstocks accepted by many large-scale composting operations. The highest-quality composts tend to be produced in composting operations in which facility management decisions are made with consideration on their impact on the economic, physical, and chemical parameters of the end product.
Impact of Biotechnology on the Environment: Challenges and Opportunities
Authors: Lemaux Peggy G.
Published: February 2019

The major challenge facing society in the 21st century is to feed and provide shelter for increasing numbers of people while protecting human health, our natural resource base, and the environment. To accomplish this, we must combine traditional technologies that stress conservation with modern technologies that rely heavily on biologically based solutions. Biotechnology, by its historical definition, has play an important role in environmental clean-up, but the contemporary practices of biotechnology will lead to more-sophisticated approaches. These technologies will allow clean-up of existing contamination and even prevention of contamination through more-sensitive and accurate monitoring systems. One of the most important advances is in bioremediation, in which microorganisms and plants remove contaminants from the soil or water and concentrate of volatilize them. In addition, plants are being modified through the changing of single genes so that they are less susceptible to pathogenic microorganisms, viruses, or insects, and more efficient in nitrogen utilization. The use of such modified plants, in concert with good agricultural practices, should lead to reductions in chemical inputs of pesticides and fertilizers. Strategies have also been developed that permit the “manufacture” in plant “pharms” of industrial products that are now produced through the use of nonrenewable resources. These biological approaches are part of the cadre of tools that we need to solve the problems of the next century. In addition, these tools will be instrumental in understanding the basic biological systems upon which the solutions to many of these challenges will come. Biotechnology is not a technological fix, but it should form part of the mind-set from which we design our strategies.