bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential Relationship between Peach Tree Short Life Symptomology and Aberrant Wood Anatomy
Authors: Werner Dennis , Parker Michael L. , Wheeler Elisabeth
Published: February 2019

Peach tree short life (PTSL), a major disease complex impacting peach culture in the southeastern United States for decades, accounts for millions of dollars of losses annually. In spite of the overwhelming amount of research that has been conducted on PTSL, many uncertainties still exist regarding the factors involved in the syndrome and the true cause of tree death. As a consequence, we examined the wood structure and anatomy of 6-year-old peach trees, some showing the initial visible symptoms of PTSL, and others that appeared unaffected and healthy. Very dramatic differences in wood anatomy were observed between healthy and stricken trees. Stricken trees showed a total lack of vessel formation in some earlywood zones, a decrease in vessel formation in latewood, and a marked increase in ray parenchyma cells. Healthy trees showed normal vessel and ray formation. Preliminary results indicate that in some way PTSL may be associated with increased gum production in the xylem and decreased earlywood vessel production, thereby significantly reducing water conduction, leading to tree death. Results of studies currently in progress to further investigate this hypothesis will also be presented.
Rootstock, Time, Technique, and Quantity of Nitrogen Effects on Production, Mineral Nutrition, and Postharvest Quality of `Fuji' Apple
Authors: Fallahi Esmaeil , Simons Brenda R.
Published: February 2019

The influence of three rootstocks, various levels of soil-applied nitrogen in fall, and spring spray applications with and without minimum ground nitrogen on tree growth, productivity, leaf and fruit nutrient partitioning, and postharvest quality of fruit at harvest and after storage in `B.C. 2 Fuji' apple was studied over several seasons. Early results showed that trees on M.26 and M.9 were more precocious and had higher yield and yield efficiency. Trees on M.9 had significantly higher leaf Ca and incidence of sunburned fruit than those on other rootstocks. Trees on M.7 had larger fruit and higher leaf N, K, and Cu, but had lower fruit starch degradation pattern (SDP) and leaf Ca. Soluble solids at harvest were lower in fruit from trees on M.26 rootstock. Trees with fall nitrogen application had lower leaf N and better fruit color. Lower quantities of N application had smaller fruit but better fruit color and higher firmness at harvest. Fruit from all rootstocks did not produce ethylene for several days in the ripening chambers. After this period, fruit on M.9 rootstock produced ethylene before those from other rootstocks. Trees established with only nitrogen spray without any ground application had leaf N deficiency after they started bearing fruit. Establishment of a new `Fuji' orchard based on only nitrogen spray produced weak trees with low yield and yield efficiency, while addition of a small quantity of ground-applied N improved tree growth and fruit quality.
Gene Transfer for Enhancing Plant Disease Resistance to Bacterial Pathogens
Authors: Zhang Zhanyuan , Coyne D.P. , Mitra A.
Published: February 2019

Gene transfer can provide plants with a novel source of disease resistance. Two different antibacterial peptides, Shiva-1 and lactoferrin, were tested in vitro for antibacterial activity. The former is from cecropin B in insects, and the latter from human or mammal fluids such as milk. Both peptides exhibited high antibacterial activity against all tested gram-negative phytopathogenic bacterial strains. Lactoferrin was more lethal than Shiva-1. A particular lactoferrin domain showed a much higher activity against bacterial strains. A gene encoding lactoferrin was then transferred to Nicotinia tabacum L. xanthi-nc to evaluate the gene expression using Agrobacterium. Stable transformation was confirmed by Southern, Northern, and Western blot analysis. Delayed wilting of the transgenic plants inoculated with Pseudomonas solanacearum was observed. A significant positive relationship between the gene expression levels and resistance was also found by either Northern or Western blotting. Biolistic transformation using a gene gun is currently underway to transfer this novel gene to common beans.
Comparison of Methods to Transform Embyrogenic Cotyledons of Melon
Authors: Gray D.J. , Hiebert E. , Lin C.M. , Kelley K.T. , Compton M.E. , Gaba V.P.
Published: February 2019

Agrobacterium-mediated transformation (AMT) was compared with a particle bombardment (PB) for stable transformation of `Eden Gem', a melon with high embryogenic potential. Pretreated cotyledonary explants were either wounded via particle bombardment prior to Agrobacterium infection or were bombarded with plasmid-coated gold microparticles, using a modified particle inflow-type gun. Although similar numbers of embryos initially were obtained with each method, most produced via AMT became abnormal, possibly due to the growth-regulatory effects of the antibiotic mefoxine, which was used to inhibit Agrobacterium. Stably transformed plants and progeny were obtained only with PB, as determined by detection of the NPTII gene in R0 plant by Southern hybridization and, in progeny, by PCR amplification.
Morphological Trait QTL Mapping in Tomato Recombinant Inbred Line Population
Authors: Paran I. , Goldman I.L. , Zamir D.
Published: February 2019

Quantitative trait loci influencing morphological traits were identified by restriction fragment length polymorphism (RFLP) analysis in a population of recombinant inbred lines (RIL) derived from a cross of the cultivated tomato (Lycopersicon esculentum) with a related wild species (L. cheesmanii). One-hundred-thirty-two polymorphic RFLP loci spaced throughout the tomato genome were scored for 97 RIL families. Morphological traits, including plant height, fresh weight, node number, first flower-bearing node, leaf length at nodes three and four, and number of branches, were measured in replicated trials during 1991, 1992, and 1993. Significant (P ≤ 0.01 level) quantitative trait locus (QTL) associations of marker loci were identified for each trait. Lower plant height, more branches, and shorter internode length were generally associated with RFLP alleles from the L. cheesmanii parent. QTL with large effects on a majority of the morphological traits measured were detected at chromosomes 2, 3, and 4. Large additive effects were measured at significant marker loci for many of the traits measured. Several marker loci exhibited significant associations with numerous morphological traits, suggesting their possible linkage to genes controlling growth and development processes in Lycopersicon.
Nitrogen-Yield Relationships in Greenhouse Roses
Authors: Cabrera Raul I. , Evans Richard Y.
Published: February 2019

The establishment of critical tissue N (Ncrit) for greenhouse rose production has been primarily based on visual symptoms of N deficiency, with relatively less consideration to yield parameters. This work examined the relationship between rose leaf N concentration and flower yield and quality. Microlysimeter-grown `Royalty' rose plants were irrigated with complete nutrient solutions containing N concentrations of 30, 60, 90, 120, 150, and 220 mg·liter–1. Results after 1 year indicated no significant differences in total dry weight, number of flowers, and stem length for plants irrigated with 90 to 220 mg·liter–1 N. Tissue N concentrations were significantly lower for plants that received 30 or 60 mg N/liter. Estimated Ncrit for yield parameters were ≈2.7% of leaf dry weight. Chlorophyll content and color leaf attributes (hue, chroma, and value) were correlated with tissue N concentration. The results suggest that the rate of N application typically recommended for greenhouse roses is considerably higher than necessary.
Utilization of Aquaculture Effluent to Supplement the Water and Nutrient use of Native Plant Nursery Production
Authors: Khan Masud A. , McCrimmon James N.
Published: February 2019

The multiple use of water from aquaculture to supplement irrigated crop production could minimize the cost of growing fish and irrigating crops. Aquaculture effluent was utilized to supplement the fertility and irrigation of six native shrub species (big sage, fourwing saltbush, mountain mahogany, Mormon tea, rubber rabbitbrush, and winterfat). Plants were established in two container types: 20-liter standard polypot and nonwoven UV-stabilized Duon synthetic fiber growbags. The plants were irrigated with fish effluent or city water. Plants irrigated with fish effluent were not given any fertilizer treatment, while plants irrigated with city water were fertilized with Osmocote®. Fish effluent was suitable for production of fourwing saltbush, rubber rabbitbrush, big sage, and winterfat. Fourwing saltbush irrigated with effluent had the best survival rate, while mountain mahogany irrigated with effluent had the poorest growth and survival rates. Big sage, rubber rabbitbrush, and winterfat had better growth and survival rates in the growbags, while Mormon tea had better growth and survival rate in the polypot containers.
Multiplication of Bigger Potato Tubers by Sprout Cutting can Produce More Than 140 Cuttings in 16 Days
Authors: Frève Andrew
Published: February 2019

The multiplication technique by sprout cutting has been improved at St-Jean-sur-Richelieu in 1994. The tuber size has been increased to medium-large tubers and two different pre-sprouting periods has been extended to 190 days. In one trial, potatoes of 20 seedlings were warmed up after 4 to 8 weeks of storage at 3C and were placed under dry conditions under light or not, for more than 6 months. They were planted in flats (28 × 53 cm) filled with a soil mixture at 16 h of light 22–24C. When 50% of the sprouts had 3 to 4 cm, they were placed in the dark for 3 days or less. The sprout cutting was done the day after returning to the initial lighting condition. The tubers were sprout-cut after 6, 10, 16, 20, 24, and 32 days after planting. A yield of more than 90 sprout cuttings in 26 days was obtained with seven seedlings. LP86065 gave 140 cuttings in 16 days. In another trial, tubers with 7 months of cold storage were tested with the technique. In 23 days, `Superior' and LP85619 gave an average of 68.4 sprout cuttings in 23 days with only three steps of multiplication. A third trial with different periods of storage and pre-sprouting will be discussed. The multiplication rate depends on may factors, such as: firmness, number of sprouts by eye and eyes by tuber, sprouting conditions, and cultivar.
Strawberry Fruit Temperature Affects Sensitivity to Bruising from Impact and Compression Forces
Authors: Ferreira M.D. , Sargent S.A. , Brecht J.K. , Chandler C.K.
Published: February 2019

Individual strawberry (Fragaria ×ananassa Duch.) fruits at cooled or ambient pulp temperatures were subjected to compression or impact forces to determine sensitivity to bruising. Fruits were more resistant to compression bruising at lower temperatures, but were more resistant to impact bruising at ambient temperatures. `Chandler' fruits at 1C or 30C were compressed (9.8 N for 2 s); after 24 h @ 24C, bruise volumes were 0.27 cm3 and 0.65 cm3, respectively. Following a single impact from 13 cm, fruits at 1C or 24C had bruise volumes of 0.21 cm3, and 0.10 cm3, respectively. Increasing impact height to 38 cm caused bruise volumes of 0.31 cm3 and 0.16 cm3 for fruits at 1C and 24C, respectively. The potential exists to improve packout quality and efficiency for value-added strawberry packs. Due to greater resistance to impacts at ambient temperatures, strawberries could be bulk-transported to a central facility, and graded and packed on an appropriately designed packing line. Care must be taken to avoid compression bruising at harvest.
Reducing Superficial Scald of Apples and Pear with Naturally Occurring Triterpenoid Compounds
Authors: Curry Eric A.
Published: February 2019

Superficial scald is a physiological skin disorder of apples and pears that develops in cold storage and that often increases in severity after the fruit is removed. It is thought to be associated with the accumulation of farnesene in the epithelial tissue. Currently used methods of controlling scald are diphenylamine (DPA) drenches, and controlled atmosphere (CA) to a limited extent. In order to expand the methods available to control scald, we have been investigating the potential of a number of naturally occurring compounds applied to the fruit surface by drenching or by topical application. Fruit were treated either by wiping the fruit surface with technical-grade material and then removing the excess, drenching whole fruit in aqueous emulsions, or drenching fruit in combinations of heat plus emulsion. After treatment, the fruit was air-dried for 30 min and then placed either in regular or CA storage for 6 months, after which time they were placed in a dark room at 68F for 7 days. Scald was evaluated and fruit condition assessed. Results from 3 years indicate farnesene and squalene reduce scald in apples and pears.
Studies of the Vigor and Productivity of Micropropagated Trees
Authors: Walsh C.S. , Allnutt F.J. , Welsh G.R , Zimmerman R.H.
Published: February 2019

A planting to compare budded apple trees (M7a, Ml11) and tissue-culture-(TC) propagated trees was established in 1985. `Golden Delicious' and `Gala' trees were more productive than other cultivars and appeared better-suited to micropropagation. High cumulative yields per tree were harvested regardless of rootstock. `McIntosh', `Delicious', `Mutsu', and `MacSpur' trees were less precocious and more responsive to size-controlling rootstocks. To control tree size prior to bearing and minimize propagation time, trees were set as containerized transplants in a subsequent trial begun in 1986. Small containerized trees were set directly into the orchard. Setting trees in this manner has restricted tree size without delaying bearing. `Oregon Spur II' trees and `Empire' trees are now about 4 m tall. Trees have wide branch angles and numerous spurs. To further control tree size, trees were root-pruned with a Vermeer tree spade in 1991. In the year following, treated trees flowered profusely but did not fruit. Since then, cropping has controlled tree size. Ten years ex vitro `Granny Smith', `Oregon Spur II', and `Empire' trees can be managed without ladders. The goals of this study were: 1) to avoid “short life” problems and 2) develop a management scheme that would allow rapid entry of “bioengineered” cultivars into commercial orchards. Based on our research, selecting precocious cultivars or spur-type clones, in combination with transplanting 3 to 4 months ex vitro and root pruning show promise toward accomplishing these goals.
Evaluation of Commercial Potential of Asian Pear Cultivars in South Carolina
Authors: Reighard Gregory L.
Published: February 2019

An Asian pear variety trial consisting of 13 cultivars replicated 12 times was planted in 1989 near Columbia, S.C. For 6 years, cultivars were evaluated for commercial fruit production. The Chinese types `Ya Li' and `Shin Li' bloomed earliest (early March), whereas Japanese types such as `Twentieth Century' and `Choju' bloomed 10 to 12 days later. The largest trees were `Ya Li', `Shinsei', and `Shin Li', and the smallest were `Shinko', `Shinsui', and `Twentieth Century'. All cultivars on P. betulaefolia rootstock had suckers, with `Chojuro' and `Shinko' trees having the fewest. `Kosui' and `Shinsui' defoliated first each fall. Average fruit yields in kg/tree were largest for `Ya Li', `Shinsui', `Shin Li', and `Twentieth Century'. Fruit size was large (>200 g) for the Chinese types such as `Ya Li', `Shin Li', and `Daisu Li', but small (<100 g) and non-commercial for `Twentieth Century'. Fruit maturity dates were consistent year to year, with `Choju' and `Shinsui' ripening first (early July) and the Chinese types ripening last (mid-August). Low return bloom (i.e., alternate bearing) was observed after a heavy crop year. Winter injury, as evidenced by bark cracking on the southwest side of the trunk, was severe in 1993–1994. However, `Ya Li' suffered no cold damage. Fireblight was first observed in the 1992, and increased in 1993 and 1994. `Choju', `Shinseiki', and `Kosui' were the most-susceptible cultivars, while `Ya Li', `Shinsui', and `Shinko' were the most tolerant.
Intermittent CaCl2 Sprays during Rain to Prevent Sweet Cherry Cracking
Authors: Fernandez R. Thomas , Flore James A.
Published: February 2019

Fruit of sweet cherry (Prunus avium L.) crack during or after rain due, in part, to absorption of water through the fruit surface driven by the water potential gradient. In 1972, J. Vittrup-Christensen suggested that overhead misting of calcium salts during precipitation may be an effective way to prevent cherry cracking by reducing the water potential gradient. We tested this hypothesis by designing a computer-controlled irrigation system to intermittently spray a 10% CaCl2 solution on trees during rain events. Spray emitters were placed in the middle and at the top of the canopy. The program turned the system on for 90 s at each 0.3 mm of rain and monitored daily rainfall and accumulated mist times. Two `Emperor Francis' and two `Ulster' were treated with equal number of controls. Intact and cracked cherries were counted on four branches per tree at three times when cherries were susceptible to cracking. Overall, cracking was reduced from 33% to 11% by the CaCl2 spray at the end of the experiment. Treated `Ulster' had 9% cracked fruit, while control had 43% cracked fruit. Differences for `Emperor Francis' were not significant. Phytotoxicity was estimated at about 15 % of leaf area. This system will be reevaluated in 1995 with the added objective of quantifying and reducing phytotoxicity.
Growth Comparison of Trees Produced under Three Production Methods and Two Irrigation Treatments
Authors: Tolan Roberta J. , Klett James E.
Published: February 2019

Patmore green ash (Fraxinus pennsylvanica `Patmore'), Bur oak (Quercus macrocarpa), and Austrian pine (Pinus nigra), were used to measure growth differences of trees produced using three different production methods: balled and burlapped, plastic container, and fabric container (grow bag). Two irrigation frequencies were also established. A pressure chamber was used to measure the xylem water potential and to determine tree water requirements and irrigation scheduling. The balled and burlapped trees showed the least new growth of the three production methods across all three tree types. The production method showing the most new growth varied by genera. Plastic container ash trees grew considerably more than the fabric container ash; fabric container oak grew significantly more than plastic container oak; and there was no measurable difference between the new growth of the plastic container and fabric container pines. The fabric container transplants required more frequent irrigation than did the balled and burlapped trees. Under high temperature and drought conditions, fabric container trees showed stress earlier than did the balled and burlapped or plastic container trees.
Genotype-by-environment Interaction in Musa Germplasm Revealed by Multi-site Evaluation in Sub-saharan Africa
Authors: Ortiz Rodomiro , Vuylsteke Dirk
Published: February 2019

Two multilocational trials, one comprising 18 Musa clones in three locations and another of 20 genotypes across 11 locations, were set up in 1991 and 1992, respectively, to assess the genotype-by-environment interaction (GxE) for important traits and to select stable high-yielding and black sigatoka (BS)-resistant genotypes. Combined ANOVAs showed significant differences among environments and among genotypes for all traits. GxE affected all growth and yield parameters, except fruit girth. Host response to BS disease also showed significant GxE, but there was no cross-order season-by-year interaction. Hence, genotypic response to BS can be assessed in 1 year during the rainy season, when disease pressure is highest. Genotype-by-location effects were more important than the nonsignificant genotype-by-year effects, supporting the need for multilocational trials. Stability analysis showed that full-sib plantain hybrids (TMPx1) exhibited different host responses to BS as well as different interaction patterns, suggesting that selection for stable BS resistance is possible. The BS-resistant TMPx genotypes had higher yields than the plantain landraces, but showed differences in yield stability. TMPx 1658-4, 2796-5, 5511-2, and 6930-1 have been selected as stable high-yielding hybrids, while the initial best selections (TMPx 548-4 and 548-9) were top yielders only in good environments. [Vuylsteke, D., R. Swennen, and R. Ortiz. 1993. Registration of 14 improved tropical Musa plantain hybrids with black sigatoka resistance. HortScience 28:957–959.]
Inheritance of Resistance to Root-know Nematode (Meloidogyne arnaria) in Cucumber (Cucumis sativus)
Authors: Walters S. Alan , Wehner Todd C. , Barker Kenneth R.
Published: February 2019

The inheritance of resistance to M. arenaria races 1 and 2 in Cucumis sativus var. hardwickii (R.) Alef. line LJ 90430 was studied in several crosses with cultivated cucumber (C. sativus L.). Initially, parents, F1, F2, and BC1 to both parents of `Sumter' x LJ 90430 tested in a split-root experiment showed that resistance was quantitative. In addition, it appeared that the same genes were controlling resistance to race 1 and race 2 of M. arenaria (genetic correlation of 0.97 and 0.99 for gall index and egg mass data, respectively). In later greenhouse experiments, two other families were evaluated (`Addis' x LJ 90403 and `Poinsett 87' x LJ 90430) for inheritance of resistance to M. arenaria race 1. In all crosses using gall index data, additive variance was the largest component of genetic variance, and estimates of narrow-sense heritability ranged from 0.50 to 0.85 (0.57 to 0.81 for broad-sense heritability). Estimates of the minimum number of genes (effective factors) using gall index data ranged from 1.1 to 2.7 (0.2 to 0.3 for egg mass data).
Ccreening Onions (Allium cepa L.) and Other Allium spp. for Botrytis Leaf Blight Resistance
Authors: Walters Thomas W. , Ellerbrock Leroy A. , van der Heide Jan J. , Lorbeer James W. , LoParco David P.
Published: February 2019

Greenhouse and field methods were developed to screen Allium spp. for resistance to Botrytis leaf blight (caused by Botrytis squamosa Walker). In the green-house, plants were sprayed with laboratory-grown inoculum and incubated in a temperature-controlled enclosure containing an atomizing mist system. For field inoculations, a portable misting system with windbreaks was erected, and the plants were sprayed with laboratory-grown inoculum. Greenhouse and field incubation conditions maintained leaf wetness without washing inoculum from the leaves. Botrytis leaf blight symptoms in greenhouse and field evaluations were identical to symptoms in commercial onion fields. A total of 86 selected USDA Allium collection accessions were evaluated using these methods. All A. fistulosum accessions and A. roytei were highly resistant to immune, as were most accessions of A. altaicum, A. galanthum, A. pskemense, and A. oschaninii. Nearly all of the A. vavilovii and A. cepa accessions were susceptible. However, one A. cepa accession (PI 273212 from Poland) developed only superficial lesions, which did not expand to coalesce and blight leaves. This work confirms previous reports of Botrytis leaf blight resistance in Allium spp., and suggests that strong resistance exists with A. cepa.
Zoysiagrass Rooting and Drought Tolerance are Reduced by Frequent Irrigation
Authors: Qian Y.L. , Fry J.D.
Published: February 2019

Textbook recommendations suggest that turf should be watered deeply and infrequently to encourage drought resistance. Data supporting this recommendation are lacking, however. Studies were done to determine the influence of irrigation frequency on `Meyer' zoysiagrass (Zoysia japonica Steud.) rooting and drought resistance. Turf was established on a silt loam soil in 27-cm-diameter by 92-cm-deep containers in the greenhouse. Irrigation was performed daily or at the onset of wilt with a water volume equal to daily or cumulative evapotranspiration of well-watered turf in small weighing lysimeters. After 90 days of irrigation treatments, a dry-down was imposed during which no additional water was applied for >50 days. Compared to turf irrigated daily, turf watered at the onset of wilt exhibited: i) lower (more-negative) leaf water and osmotic potentials prior to the onset of drought; ii) higher leaf water potential and better turf quality at the end of dry-down; and iii) deeper rooting as indicated by lower soil moisture content at 50- and 70-cm depths at the end of dry down.
Evaluation of Four Herbaceous Perennials under Increasing Levels of Drought Stress
Authors: Hillock David , Klett James E.
Published: February 2019

Four herbaceous perennials Aquilegia caerulea `McKana's Giant', Gaillardia aristata, Gypsophila paniculata `Fairy's Pink', and Callirhoe involucrata were subjected to increasing levels of drought stress and evaluated for ornamental quality and performance in the landscape. Drought stress was imposed by irrigation treatments of 100%, 75%, 50%, 25%, and 0% of reference evapotranspiration (ET0) in 1994. Irrigation treatments resulted in Aquilegia exhibiting a decline in plant growth and appearance below the 50% ET0 treatment. Callirhoe grown at the 100% ET0 irrigation treatment were larger than the plants in any other treatment. Gaillardia receiving some irrigation (25% to 100% ET0) were generally larger than those that received no supplemental irrigation (0% ET0). A decline in plant appearance and growth was observed with Gypsophila with lowering irrigation treatments.
Influence of Irrigation Scheduling on Groundcover Performance
Authors: Pittenger Dennis R. , Shaw David A. , Hodel Donald R. , Richie William E.
Published: February 2019

The performance of six landscape groundcover species was evaluated when irrigated at 30% of ET0 at irrigation schedules of three times per week, once per week, once every 2 weeks, and once every 4 weeks. Potentilla tabernaemontani could not be sustained under any of the treatments. For the other species (Baccharis pilularis, Drosanthemum hispidum, Vinca major, Osteospermum fruticosum, and Hedera helix) there were no season-long differences in a species' performance or density due to irrigation frequency, but there were significant differences among species across irrigation treatments. Drosanthemum and Osteospermum provided good overall appearance and density consistently through the season. Baccharis maintained acceptable performance most of the irrigation season, while Vinca and Hedera became unacceptable in appearance in mid-season. Soil moisture content differed among species, but was not consistently different between irrigation treatments.
Effect of Plant Density and Cultivar on the Fruiting Response of Strawberry using the Winter Annual Hill Culture System
Authors: Albregts Earl E. , Chandler Craig K.
Published: February 2019

Four strawberry (Fragaria ×ananassa, Duch.) cultivars were grown in a winter strawberry fruiting study using the annual hill cultural system and polyethylene-mulched beds during two seasons. Plants were set on 15, 30, 45, and 60 cm in row-plant spacing with two rows per bed spaced at 45 cm. Increasing plant density in the fruiting field generally increased early fruit yield and sometimes total fruit yield during two seasons. Yields of cull fruit were also increased with increased plant density. Daughter plant production decreased with increased plant density. Growers should consider planting costs, fruit rot, and harvesting problems when selecting the plant density for fruit production.
Response of `Chardonnay' Grapevines to Training and Crop Control
Authors: Zabadal Thomas J. , VanEe Gary R. , Dittmer Thomas W. , Ledebuhr Richard L.
Published: February 2019

Growing conditions in Michigan can threaten the yield and acceptable fruit quality of `Chardonnay' grapevines. Three grapevine training systems, mid-wire cordon (MWC), umbrella kniffin (UK), and a combination of the two (MWC-UK) were evaluated under Michigan growing conditions to determine their influence on yield, fruit quality, cluster compactness, incidence and severity of Botrytis bunch rot, and trellis fill. Vines were grown on C3309 rootstock and pruned to 44 nodes per kilogram of cane prunings. The MWC-UK treatment had an additional 30 nodes per vine retained, and the crop level on these nodes was removed after fruitset. Over a 2-year period, UK and MWC-UK trained vines had fruit soluble solids about 1 °Brix higher and yields were 48% and 63% higher than MWC trained vines, respectively. MWC-UK trained vines consistently out-performed MWC trained vines for all variables measured, while UK-trained vines provided an intermediate response.
Do Chemical Treatments that Influence Inflorescence Necrosis Severity affect Grape Flower Cluster NH4+?
Authors: Creasy Glen L. , Breen Patrick J.
Published: February 2019

A fruit-set disorder of grape, called Inflorescence Necrosis (IN), causes death of flower cluster tissue near bloom. Various chemical treatments have been reported to increase IN severity. Separate studies show that high flower cluster NH4+ is related to naturally occurring IN. We designed a field trial to determine if treatments thought to influence IN severity also affect flower cluster NH4+. One week before first bloom, flower clusters were dipped in solutions of either methionine sulfoximine (MSO, an inhibitor of NH4+ assimilation), α-keto glutarate, (NH4)2HPO4, KNO3, NAA, GA, or an emulsion solution reported to increase transpiration. Also, ethephon was sprayed on whole vines 1 week before first bloom. Flower clusters were collected 5 days after treatment. MSO increased tissue [NH4+] by almost 2-fold over that of controls. NAA and GA reduced [NH4+] a small amount, possibly due to their slightly higher fresh weights. Other dip treatments did not affect [NH4+]. Despite high [NH4+] in MSO treated clusters, there were no visual differences in IN between treatments. Ethephon increased cluster [NH4+] 20% over that of controls, but caused more severe IN. These data show that flower cluster [NH4+] is not always coupled with IN symptoms.
Genetic Analysis of Acylsugar Production in Intraspecific Populations of the Wild Tomato, Lycopersicon pennellii
Authors: Eggleston Susan L. , Lawson Darlene M. , Mutschler Martha A.
Published: February 2019

Acylsugars produced by many accessions of wild tomato (L. pennellii) mediate resistance to a number of important pests of tomato. The highly resistant L. pennellii accession LA716 accumulates high levels of acylsugars, of which 85% are in the form of acylglucoses, the rest being acylsucroses. In contrast, L. pennellii accession LA1912, which does not show the insect resistance of accession LA716, accumulates very low levels of acylsugars, of which 55% are represented by acylglucoses. The intraspecific F1 derived from crosses between the accessions LA716 and LA1912 accumulates moderate levels of acylsugars, of which, like its LA716 parent, 85% are in the form of acylglucoses. Intraspecific F2 and backcross populations derived from crosses between the accessions LA716 and LA1912 were surveyed for acylsucrose and acylglucose production. These populations segregated for the ability to produce acylsugars, levels of total acylsugars produced and amount of acylglucoses as a percentage of total acylsugars. The genetic control of these traits will be discussed.
Breeding for Acylsugar-mediated Multiple-pest Resistance in Cultivated Tomato, Lycopersicon esculentum
Authors: Mutschler Martha A. , Cobb Edward D. , Liedl Barbara E. , Shapiro Joseph A.
Published: February 2019

Acylsugar mediates the resistance of Lycopersicon pennellii LA716 to several important insect pests of cultivated tomato, including potato aphid, green peach aphid, leaf miner, fruitworm, armyworm, and silverleaf whitefly. Incorporation of acylsugar-mediated multiple pest resistance could result in a significant reduction in the use of pesticidal sprays in cultivated tomato. Development of a reliable assay for acylsugar production and confirmation of the association between the resistance and acylsugars allowed us to try to breed for the trait by selecting for acylsugar-producing plants. The breeding cycle allows us to progress by one backcross generation per year. The breeding program was faced by several challenges, including interference in gene transfer by interspecific crossing barriers, and the oligogenic nature of the acylsugar-mediated resistance trait. Despite these challenges, the breeding program has produced BC3F2 plants that produce effective levels of acylsugars, are tomato-like in vine appearance, and produce seed-bearing fruit in the field without manual pollination. The current status of the program and future plans will be discussed.
The Effect of Slow-release Polymeric Derivatives of Auxins (NAA and 2,4-D) on Regeneration of Achimenes in Vitro
Authors: Vlahos J.C. , Dragassaki M. , Vasilaki A. , Assargiotaki I. , Tsatsakis A.M.
Published: February 2019

Polymeric formulations of plant growth regulators (PGR) are high-molecular weight systems in which the PGR unit can be slowly released providing prolonged action and effectiveness in a wide range of concentrations. In this study, Achimene explants were used for testing the biological activity of polymeric derivatives of NAA and 2,4-D. Shoots of Achimenes `Bella', obtained from leaf segments cultured in vitro, were transferred for 8 weeks on Murashige and Skoog (MS) medium supplemented with different levels of conventional or polymeric NAA (0, 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5 mg·liter–1) and 2.4-D (0, 0.01, 0.05, 0.1, 0.5, 1.0, 1.5 mg·liter–1), each combined with three levels of BAP (0, 0.1, 0.5 mg·liter–1). Compared to conventional NAA, twice as many shoots proliferated with higher dry weight, at 0.5 0.1, 1.0, or 1.5 mg·liter–1 polymeric NAA with 0.5 mg·liter–1 BAP. In another trial, the combination of 0.05 or 0.1 mg·liter–1 polymeric 2,4-D with 0.1 BAP gave more shoot and vigorous growth without callus formation, compared to conventional 2.4-D These results suggest that the polymeric derivatives of auxins used in this study enhance regeneration and growth of Achimenes in vitro more effectively than conventional formulations, at greater concentrations, without causing toxic or inhibitory effects.
Growth of Begonia as Influenced by Paclobutrazol Residue in Compost-amended Media
Authors: Al-Badawy Ahmed A. , Barrett James E. , Nell Terril A.
Published: February 2019

Paclobutrazol was applied as soil drench to potted petunia, and the treated plants were shorter than untreated ones. Three types of compost were then made from the treated and untreated plants: the shoots, the medium (including roots), and both shoots and medium. They were mixed with Vergro Klay Mix at the ratios of 0%, 5%, 10%, 20%, and 40% (v/v). In a factorial experiment, plugs of Begonia semperflorens cv. Gin were planted in the media with compost. Plants grown in media containing paclobutrazol residue were shorter and had less dry weight compared to those grown in media containing no paclobutrazol residue. Compost ratios at 5% and 40% reduced plant height to 65% and 42% and shoot dry weight to 55% and 20% of the control plants, respectively. These results indicate that residues from plants treated with paclobutrazol may carry over in soil of landscape beds and affect the growth of subsequent crops grown in that soil.
Distribution of Paclobutrazol in Media Following Drench Applications
Authors: Million Jeff B. , Barrett James E. , Nell Terril A.
Published: February 2019

Drench applications of paclobutrazol (PBZ) are becoming increasingly popular as a means for controlling height in potted plants, and research is being conducted to quantify the distribution of PBZ following applications. In one trial, 120 ml of 0 or 1 mg 1-1 PBZ were applied to 15-cm pots filled with either Vergro Klay Mix (no bark) or Metro Mix 500 (bark). A bioassay using broccoli (Brassica oleracea L. Italica) seedlings was used to quantify PBZ in leachates and media following treatment drenches. Leachate PBZ concentrations were lower for Vergro than for Metro Mix 500; however, leachates for both media were <0.1 mg·liter–1. Concentrations of PBZ in media decreased with depth and were four to 10 times higher in the uppermost 2.5 cm than in lower horizons. For the uppermost 2.5 cm of media, higher PBZ concentrations were recovered in Metro Mix 500 than in Vergro. A follow-up study will compare surface vs. subsurface application methods on the movement of PBZ into pots.
Paternity Analysis in Higher Polyploids
Authors: Buteler Mario I. , LaBonte Don , Macchiavelli Raul
Published: February 2019

The breeding of new sweetpotato varieties is a highly inefficient process, confounded by incompatibility, poor fertility, open-pollination, and its hexaploid nature. Upwards of 12 to 20 lines are currently combined in open-pollinated nurseries based on good horticultural characteristics. Most progeny after several years of selection can be traced back to just three or four maternal lines. A method that would identify the paternal parent of superior progeny would enable breeders the ability to combine parents that exhibit superior combining ability in more-efficient, smaller nurseries. The objective of this work is to explore by means of computer simulation the application of genealogy reconstruction techniques on hexaploid individuals with PCR-based data. The progeny obtained on each female parent is fractionally assigned to each male with non zero exclusion probability proportional to its paternity likelihood. Computer simulations show that at least five different alleles per loci are needed to reach a reasonable discriminatory level. Also, the number of loci scored should not be less than 20. An increment in the number of alleles or loci increases the discriminatory power; but, the number of alleles produces a far more important effect than the number of loci.
Physiological Responses of Citrus to High-pressure Washing
Authors: Petracek Peter D. , Kelsey D. Frank
Published: February 2019

High-pressure washing (>689 to 3446 kPa or 100 to 500 psi at the spray nozzle) has been used recently in citrus packinghouses to improve the action of surfactant solution and brushing on the removal of dirt and superficial molds. Although high-pressure washing has no obvious detrimental effect on citrus fruit (e.g., no cellular breakage), its effects on physiology have not been fully examined. In this study gas samples were taken from the fruit core of `Orlando' tangelos, `Hamlin' oranges, and `Ruby Red' and white `Marsh' grapefruit prior to and following washing. An apparent wound ethylene response was measured for all varieties and was a function of prolonged exposure (>20 s) and excessive pressure (>2067 kPa). For the responding fruit, internal ethylene was initially detected about 3 h after washing, reached a maximum around 24 h (range: 0.1 to 0.6 ppm), and diminished to near background levels (0.0 ppm) after 48 h. No wound ethylene was observed when fruit were washed for the recommended exposure time (10 s) and pressure (1379 kPa). Concurrent decreases in internal O2 and increases in CO2 were observed for white and red grapefruit. High-pressure washing (1379 or 2757 kPa) did not affect water loss and water, O2, and CO2 exchange. The effects of subsequent waxing of the fruit (increased internal ethylene and CO2 levels and reduced of internal O2 levels) were amplified by washing at the higher pressure (2757 kPa).
Changes in the Respiratory Activity of Papaya Fruit Following Storage in Low-oxygen Atmosphere
Authors: Rahman Abd. Shukor
Published: February 2019

Controlled-atmosphere (CA) storage of fruits employing low O2 and/or elevated CO2 have been used to reduce respiration and other associated metabolic activities. Papaya fruit cv. Eksofika were exposed to 2%, 5%, and 21% (air) O2 for 4 weeks at 12C. The CO2 production rates of fruit previously stored in 2% and 5% O2 were suppressed during storage, but increased upon transfer to air at 20C. Carbon dioxide production rates of low-oxygen stored fruits were slightly lower than the air-stored fruit during transfer to air, indicating a slight residual effect of low O2 on the respiratory activity of the fruit. This was highly evident in fruit stored in 2% O2 for 4 weeks. Ethylene production rates were not affected by prior storage of fruit in low-O2 atmosphere. Anaerobic metabolism did not occur in fruit stored in 2% O2 for 4 weeks, as evidenced by the RQ values close to unity and the absence of ethanol from the headspace of the respired gas. The total sugar content of ripe fruit at color score 5, previously stored in low-O2 atmosphere for 4 weeks, were not significantly different from the air-stored fruit.
Yield, Earliness, and Fruit Weight of Fresh-market Tomatoes Grown in Synthetic and Organic Mulches
Authors: Abdul-Baki Aref A. , Teasdale J.R. , Korcak R. , Chitwood D. , Huettle R
Published: February 2019

Fresh-market tomatoes (Lycopersicon esculentum Mill) cvs. Sunny and Sunbeam were grown in bare soil (BS), Horto paper (HP), black polyethylene (BP), hairy vetch (HV), crimson clover (CC), and hairy vetch plus rye (HVR) mulches. Yields were highest in HV (85.8 t·ha–1), followed by HVR 69.3 t·ha–1) and CC (65.7 t·ha–1), and averaged 47% above BP for the 3-year period. A 5- to 9-day earliness was exhibited by BP over other treatments. Fruit weight was significantly higher in all three organic mulch treatments than in the other three treatments. Mulch biomass was highest in HVR (5.91 t·ha–1), whereas N fixation was highest in HV (188 kg·ha–1). Tomato harvest was extended by the HV treatment over the BP treatment by 3 to 4 weeks, during which tomato prices were higher than those in early or mid-season.
Towards a Sustainable Fruit Industry in Europe: Research and Strategies
Authors: Sansavini S.
Published: February 2019

The European Union's fruit industry is currently beset by marked surplus output, formidable market competition from non-EU countries, and strong consumer demanded for enhanced quality. This latter issue is particularly complex because it involves not only the fruit's genetic, esthetic, sensory, and taste characters, but also pre- and postharvest produce management practices and their impact on the environment and human health. The main thrust of the response to the challenges posed by these quality factors is integrated fruit production (IFP), a policy sustainable crop growing that the EU can support financially. Research has been directly involved in IFP and the directions in which it is moving. It has developed the first EU guidelines (OILB-ISHS), which initially covered pome crops and were later extended to cover all fruits, and the field, harvest, handling, storage, and market monitoring and quality-control techniques needed to implement them. These methods include biological and integrated disease and pest control, the introduction of plant material resistant to biotic and abiotic stresses, the development of field management practices to enhance plant defense and cropping-control mechanisms, the use of energy-saving irrigation and nutrient input techniques, the modeling of plantations, training systems and tree-bearing control, and advanced fruit storage, packaging, and transport methods. The updated advances in these areas are reported and discussed.
The Organic Cultivation Practices in Tea and Coffee
Authors: Raman K. , Jothikumar P.D. , Machia C.S. , Muthanna M.C.
Published: February 2019

Traditionally, the tropical plantation crops such as tea and coffee are intensively cultivated. The increasing concern about the environment, ecology, and the realization that the continued use of chemical inputs is causing the starvation of soils are forcing us to look into alternatives such as sustainable farming. Being perennial crops, there are no examples to follow in the case of plantation crops. By trial and error, we have switched over to organic cultivation of 340 ha of tea and 34.5 ha of coffee. The produce from these, i.e., black teas and arabica and robusta coffees, are being cultivated, processed, and packed conforming to most-stringent organic standards and world-renowned certification authorities, such as IMO, IFOAM, MOA, et. al. have vouchsafed their authenticity. The strategies adopted, methodologies of farming, economics, and the benefits accruing from such farming will be discussed.
Prebloom Treatments to Alleviate Cold Injury in Apple
Authors: Stover E.W. , Paine T.E. , Stiles W.C.
Published: February 2019

Damage to xylem subtending apple buds is often observed following very low winter temperatures. Reports suggest that prebloom application of boron, zinc, and urea facilitate recovery. Prebloom nutrient treatments were applied to `McIntosh' and `Empire' at three sites in Spring 1994. The following treatments were applied to drip at half-inch green: boron (22.8 mM, solubor); Zn-EDTA (0.75 mM); boron and Zn-EDTA; boron, Zn-EDTA, and urea (59.4 mM). Another treatment used boron and Zn-EDTA at half-inch green, followed by boron, Zn-EDTA, and urea at pink. Spur leaf area, fruit set, fruit size, and seed number were determined. There were no clear treatment effects at the warmest site (mid-winter low –32C); however, this orchard was more variable than other treatment sites. The intermediate site (mid-winter low –37C) had a strong trend of increasing fruit set in `Empire' and `McIntosh' as more nutrients were applied. The combined half-inch green and pink treatment significantly increased fruit set by 23.8% compared to the untreated control. At the coldest site (mid-winter low –42C), `Empire' again displayed a strong trend of increasing fruit set with additional nutrients. All treatments combining boron and zinc significantly increased fruit set. The combined half-inch green and pink treatment increased fruit set by 43%. At this site `McIntosh' did not respond to treatment. However, `McIntosh' trees had continued active growth into late Fall 1993 and sustained severe cold injury in November. Data suggest that, when they were effective, nutrient treatments resulted in increased retention of flower buds on damaged spurs.
Cold Protection of Leatherleaf Fern in Shadehouses Using Water and Crop Covers
Authors: Stamps Robert H.
Published: February 2019

Six shadehouses were used in tests of irrigation rates and crop covers for cold-protecting leatherleaf fern [Rumohra adiantiformis (Forst) Ching]. Each shadehouse was equipped with two irrigation systems—one over-the-crop to supply heat and one over-the-shadehouse to supply water for sealing the openings in the shade fabric with ice. The over-the-crop irrigation system consisted of frost protection wedge-drive impact sprinklers providing water application rates of 0.30, 0.56, and 0.76 cm/h. Six-m × 9-m spunbonded polypropylene crop covers weighing 20 and 51 g·m–2 were tested. During radiation freezes, all water application rates protected immature fronds from damage. Damage during advective freezes decreased with increasing water application rate, but, even when crop covers were used in conjunction with irrigation, some damage still occurred. Temperatures under the lighter-weight cover were higher than under the heavier-weight one, probably because more water passed through the lighter cover to the crop. Water application rates had no effect on frond yield.