bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of Seedling Roughstalk Bluegrass and Creeping Bentgrass to Bispyribac–sodium or Sulfosulfuron
Authors: Rutledge James M. , Weisenberger Daniel V. , Reicher Zachary J.
Published: February 2019

Controlling mature roughstalk bluegrass (Poa trivialis L.; RSBG) using bispyribac–sodium (BYS) or sulfosulfuron (SUL) often yields inconsistent results. Attempting to control RSBG shortly after emergence may eliminate or reduce it with fewer inputs and less noticeable creeping bentgrass (Agrostis stolonifera L.; CBG) phytotoxicity than if treated at maturity. The objective of these studies was to determine whether BYS or SUL controls seedling RSBG with only minimal seedling CBG cover reduction. Four separate studies on either CBG or RSBG were conducted in spring or fall of 2007 and repeated in 2008 to simulate spring or fall fairway establishment. Studies were arranged as split plots with application timing (7, 14, 21, or 28 days after CBG emergence) as main plots and subplots were herbicide treatments in a 2 × 5 factorial with BYS or SUL applied once at five uniformly increasing rates of 0, 18, 37, 55, and 74 g·ha−1 a.i. and 0, 6, 13, 19, and 26 g·ha−1 a.i., respectively. Plots were maintained at 1.3 cm and emergence was defined as ≈50% of the study area being populated with one- to two-leaf CBG seedlings. Spring-seeded stands of CBG were safely treated with BYS 14 or more days after emergence (DAE) at 55 g·ha−1 a.i. or less, whereas SUL was not safe by 28 DAE at any tested rate. Fall-seeded CBG was generally less sensitive to BYS and SUL. Sulfosulfuron resulted in excessive damage if applied to seedling CBG before 14 DAE at rates greater than 6 g·ha−1 a.i. and if applied before 21 DAE at rates greater than 26 g·ha−1. Bispyribac–sodium was safely applied as soon as 7 DAE at rates of 74 g·ha−1 a.i. or less. Chemical names used: {2,6-bis[(4,6-dimethoxypyrimidin-2-yl)oxy] benzoic acid} (bispyribac–sodium); {1-[4,6-dimethoxypyrimidin-2-yl]-3-[2-ethanesulfonyl-imidazo(1,2-a)pyridine-3-yl) sulfonyl]urea} (sulfosulfuron).
Resistance of Dry Bean and Snap Bean Cultivars to Root-knot Nematodes
Authors: Ferreira Sindynara , Gomes Luiz Antonio A. , Maluf Wilson Roberto , Campos Vicente Paulo , de Carvalho Filho José Luiz S. , Santos Daniela Costa
Published: February 2019

This study assessed the reaction of dry bean and snap bean cultivars to infection by Meloidogyne incognita (races 1, 3) and by Meloidogyne javanica, two species of root-knot nematodes. Three independent experiments were done, one for each species or race of Meloidogyne, using randomized complete block designs with four replications (plots) and four plants per plot. A plot with the susceptible tomato cultivar Santa Clara was used in each block to determine the efficiency of the inoculum and to calculate the reproduction rate for each of the genotypes assessed. The bean cultivars Aporé and Talismã were highly resistant to Meloidogyne javanica, slightly resistant to Meloidogyne incognita race 1, and moderately resistant and slightly resistant, respectively, to Meloidogyne incognita race 3. The snap bean cultivars Macarrão Atibaia and Macarrão Preferido were slightly resistant to Meloidogyne javanica and moderately resistant and susceptible, respectively, to Meloidogyne incognita race 1. The reactions of the latter cultivars against Meloidogyne incognita race 3 were very resistant and slightly resistant, respectively. The results of these experiments showed that the dry bean cultivars Aporé and Ouro Negro and the snap bean cultivar Macarrão Atibaia have potential to be used in breeding programs for a broader spectrum of root-knot nematode resistances.
Yield and Nutrient Content of Bell Pepper Pods from Plants Developed from Seedlings Inoculated, or Not, with Microorganisms
Authors: Russo Vincent M. , Perkins-Veazie P.
Published: February 2019

The effectiveness of microorganisms applied in production of vegetable transplants has had mixed results. Bell pepper (Capsicum annuum L.) transplants were grown in a greenhouse using organic methods and the organic-certified potting mix was inoculated, or not, with beneficial bacteria or arbuscular mycorrhizal (AM) fungi, or both. Other transplants were grown in the same greenhouse with a conventional potting mix, which was not inoculated. Transplants were established in the field at various planting dates in a Bernow or Stigler soil and grown using conventional or organic methods. Pod yield and nutrient contents were determined. Yields of organically grown plants were similar to those of conventionally grown plants when both were grown on the Bernow soil. When grown on both soil types, yield was higher for the Bernow than for the Stigler soil. Treatment had little effect on pod mineral content. Chlorophylls, total carotenoid, and vitamin C contents of pods from plants grown on the Stigler soil were generally lower than those from plants grown on the Bernow soil. Average pod fresh weight for plants developed from seedlings inoculated with beneficial bacteria or AM fungi was greater than that from plants developed from conventionally grown seedlings. Inoculation did not improve fresh pod weights over that from plants developed from organically grown, but not inoculated, seedlings. Amending potting mix with the microorganisms tested did not provide extraordinary benefit or detriment for use in production of bell pepper.
Characterization of Nutritionally Important Carotenoids in Bunching Onion
Authors: Kopsell Dean A. , Sams Carl E. , Deyton Dennis E. , Abney Kristin R. , Kopsell David E. , Robertson Larry
Published: February 2019

Members of the Allium genus are consumed for their culinary flavor attributes, but also contain antioxidant and anticarcinogenic phytochemicals. Bunching onions (Allium fistulosum L.) are commonly used in Asian cuisine, in which both leaves and pseudostems are consumed. Carotenoids and chlorophylls are important classes of phytochemicals gaining attention for their health attributes. The goal of our study was to characterize carotenoids and chlorophylls and identify possible genetic and environmental influences on carotenoid concentrations among A. fistulosum accessions. Twelve USDA-ARS accessions were field grown in Knoxville, TN, and Geneva, NY, during the summer of 2007. After harvest, carotenoid and chlorophyll pigments were evaluated in leaf and pseudostem tissues using high-performance liquid chromatography. We were able to identify the presence of antheraxanthin, β-carotene, chlorophyll a and b, lutein, neoxanthin, and violaxanthin in leaf tissues; however, pigments were not found in pseudostem tissues. Carotenoid and chlorophyll concentrations did not differ among accessions or between locations. It is possible that accessions evaluated in this study were a narrow genetic base or were selected based on flavor attributes and not leaf tissue pigmentation.
Physiological and Physicochemical Responses of ‘Sai Nam Phueng’ Tangerine to Commercial Coatings
Authors: Seehanam Pimjai , Boonyakiat Danai , Rattanapanone Nithiya
Published: February 2019

Tangerine fruit cv. Sai Nam Phueng was coated with six commercial coatings: Citrashine, Fomesa, Citrosol AK, Supershine-C, Zivdar, and Perfect Shine. Fruit were coated using gloved hands and stored at room temperature (23 ± 3 °C) and 56% ± 5% relative humidity. Physiological and chemical properties were recorded on Days 0, 1, 4, 7, 10, and 13. All coated fruit had lower respiration rates, reduced weight loss, higher gloss, and better appearance than control fruit. Coatings somewhat increased total soluble solids levels, but had no major effects on pH, titratable acidity, or vitamin C contents. Among the various wax formulations, tangerines coated with Zivdar, and to a lesser extent Perfect Shine, had the highest internal O2 and lowest internal CO2 levels, resulting in the lowest juice ethanol levels. Application of other coatings, especially Citrosol AK and Supershine-C, resulted in enhanced accumulation of off-flavors and decreased sensory acceptability.
Preharvest Application of 1-Methylcyclopropene Influences Fruit Drop and Storage Potential of ‘Bartlett’ Pears
Authors: Villalobos-Acuña Max G. , Biasi William V. , Flores Sylvia , Mitcham Elizabeth J. , Elkins Rachel B. , Willits Neil H.
Published: February 2019

Preharvest applications of 1-methylcyclopropene (1-MCP) were tested on California ‘Bartlett’ pears at 80 N maturity and at rates of 0, 28, and 56 mg·L−1 in 2006 and 0, 50, and 100 mg·L−1 in 2007. In 2007, a parallel experiment was conducted to compare 50 mg·L−1 1-MCP with 96 g a.i./ha 1-naphthaleneacetic acid (NAA) used commercially to control or decrease premature fruit drop. Premature fruit drop, maturity, firmness at harvest, color, softening, and ethylene production during ripening and physiological disorders were studied in fruit harvested between 7 and 21 days after 1-MCP application and either ripened at 20 °C immediately after harvest or after 3.5 to 6 months storage at –1 °C. Overall, 50 mg·L−1 1-MCP reduced the incidence of premature fruit drop when compared with the untreated fruit and fruit drop was similar to adjuvant-treated fruit and NAA-treated fruit, especially 28 days or longer after the treatment. 1-MCP was more effective in retarding color, softening, and ethylene production during ripening than delaying fruit maturation on the tree (loss of firmness), and both rates of 1-MCP tested each season yielded similar fruit responses on most evaluation times. 1-MCP's effect on ripening was lost if fruit remained on the tree 21 days or after the fruit were stored for 3.5 months in cold storage regardless of treatment concentration. A reduction of internal breakdown incidence was observed in 1-MCP-treated fruit.
Combining Linear Regression and Machine Learning Approaches to Identify Consensus Variables Related to Optimum Sweetpotato Transplanting Date
Authors: Villordon Arthur , Clark Christopher , Smith Tara , Ferrin Don , LaBonte Don
Published: February 2019

Forward and stepwise regression methods identified variables related to the influence of transplanting date on yield of U.S. #1 sweetpotatoes. The variables were mean minimum soil temperature 5 days after transplanting (DAT), wind direction at transplanting, and accumulated heat units (growing degree-days) 5 DAT. Machine learning techniques identified the same variables using leave-one-out and k-fold cross-validation methods. Growers and crop consultants, in collaboration with knowledge workers, can use this information in conjunction with public and subscription-based weather forecasts to further optimize transplanting date determination and for making risk-averse decisions. These results help to underscore the importance of consistent transplant establishment as one of the determinants of storage root yield in sweetpotatoes.
Bermudagrass Reseeding Intervals for Rimsulfuron, Simazine, and Sulfosulfuron
Authors: McCullough Patrick E. , Nutt William
Published: February 2019

Turf managers may wish to reseed common bermudagrass [Cynodon dactylon (L.) Pers.] following weed control with rimsulfuron, simazine, or sulfosulfuron applications, but establishment may be affected by herbicide residual activity. Field experiments were conducted in Georgia to investigate bermudagrass reseeding intervals for these herbicides. Application timing before seeding reduced bermudagrass establishment more than herbicide rate. By four weeks after seeding, bermudagrass cover was 15%, 53%, 81%, and 90% of the untreated from herbicides applied zero, two, four, or six weeks before seeding, respectively. Simazine at 2.24 kg a.i./ha reduced bermudagrass cover more frequently than sulfosulfuron at 0.035 and 0.07 kg a.i./ha and rimsulfuron at 0.02 kg a.i./ha. Results suggest that common bermudagrass may be safely reseeded four to six weeks after rimsulfuron, simazine, or sulfosulfuron treatments, but applications made closer to the seeding date have the potential to significantly delay establishment.
Combination of Organic and Plastic Mulches to Improve the Yield and Quality of Winter Fresh Market Bell Peppers (Capsicum annuum L.)
Authors: Wang Qingren , Klassen Waldemar , Evans Edward A. , Li Yungcong , Codallo Merlyn
Published: February 2019

Mulching in vegetable cultivation has been widely used to conserve water and improve yield. Field experiments with four treatments, including yard waste compost combined with plastic mulches in raised beds for winter fresh market bell peppers (Capsicum annuum L.), were conducted at two experimental sites [Pine Island Farm (PIF) and Tropical Research and Education Center (TREC)] in Miami-Dade county for two different years each. The treatments were: 1) control (PM): plastic mulch alone; 2) MC33: fumigation of the soil with a mixture of methyl bromide and chloropicrin and covered with plastic mulch; 3) herbicide/OM: organic mulch sprayed with herbicides (S-metolachlor and napropamide) without plastic mulch; and 4) PM/OM: organic mulch covered by plastic mulch. The treatment of PM/OM at both experimental sites in 2 years each increased the total marketable yields of bell pepper by 1.5- to 3.2-fold, total extra large fruit yields by 2.0- to 5.7-fold, and total large fruit yields by 1.4- to 2.6-fold, respectively, on average compared with the control, although some exceptions occurred between the two years at the TREC site. Under most circumstances at both experimental sites in two different years each, the PM/OM treatment also improved the total marketable yield and fruit quality (such as extra large fruits) for the first two harvests, which shows a preference to provide winter fresh market vegetables to meet a high demand. The economic benefit by PM/OM was the greatest among all the treatments. The results suggest that the application of organic mulch combined with plastic mulch can improve bell pepper yield and quality as a result of the improvement of soil fertility, especially the early harvests of winter fresh market fruits, which has shown a potential in the development of sustainable agriculture.
Leaf Gas Exchanges and Mineral Ion Composition in Xylem Sap of Iranian Melon Affected by Rootstocks and Training Methods
Authors: Salehi Reza , Kashi Abdolkarim , Lee Jung-Myung , Babalar Mesbah , Delshad Mojtaba , Lee Sang-Gyu , Huh Yun-Chan
Published: February 2019

Photosynthetic characteristics, concentrations of mineral elements in xylem sap, and some vegetative traits of ‘Khatooni’ melon were compared with those of melons grafted onto three Cucurbita rootstocks cvs., Ace, Shintozwa, and ShintoHongto, and trained with three methods: T1) no pinching and fruit thinning; T2) pinched to produce two lateral branches; and T3) pinched to two branches and all the flowers and lateral branches from lower nodes thinned. Internal CO2 and water use efficiency varied with rootstocks. Stem diameter of scions, aerial fresh and dry weights, mean fruit weight and yield, electric conductivity, pH, and sap volume per plant of grafted plants were higher in grafted melons than in the nongrafted ones. These traits were unaffected by training methods. Mineral concentrations varied considerably depending on the rootstocks and training methods used. Xylem sap collected from the decapitated stem base of grafted melons trained with T2 and T3 methods contained a higher amount of mineral ions, especially NO3−, PO43−, and K+, than did the sap from own-rooted plants. The increase in the mineral levels in sap resulting from grafting was most apparent in ‘Khatooni’ grafted onto ‘ShintoHongto’ rootstock.
Genotypic Variation in the Postharvest Performance and Ethylene Sensitivity of Cut Rose Flowers
Authors: Macnish Andrew J. , Leonard Ria T. , Borda Ana Maria , Nell Terril A.
Published: February 2019

Natural variation in the postharvest quality and longevity of ornamental plants can often be related to differences in their response to ethylene. In the present study, we determined the postharvest performance and ethylene sensitivity of cut flowers from 38 cultivated Hybrid Tea rose genotypes. The vase life of the cultivars varied considerably from 4.5 to 18.8 days at 21 °C. There was also substantial variation in the degree of flower opening among genotypes. Exposure to 1 μL·L−1 ethylene for 24 h at 21 °C reduced the longevity of 27 cultivars by 0.8 to 8.4 days (18% to 47%) by accelerating petal wilting and abscission. Ethylene treatment also significantly reduced rates of flower opening in 17 sensitive cultivars and in six cultivars that showed no ethylene-related reduction in vase life. Five cultivars showed no reduction in vase life or flower opening in response to ethylene exposure. Pre-treating stems with 0.2 mm silver thiosulfate liquid or 0.9 μL·L−1 1-methylcyclopropene (1-MCP) gas for 16 h at 2 °C reduced the deleterious effects of ethylene. The release of 1-MCP from two sachets containing EthylBloc™ into individual shipping boxes also protected flowers against ethylene applied immediately after a 6-d commercial shipment. The duration of protection afforded by the 1-MCP sachet treatment was greatest when flowers were maintained at low temperature.
Cryptic Scale Infestations on Cycas revoluta Facilitate Scale Invasions
Authors: Marler Thomas E. , Moore Aubrey
Published: February 2019

The cycad aulacaspis scale (Aulacaspis yasumatsui Takagi) has invaded numerous geographic regions in the past 15 years. The sequential invasions have decimated many Cycas nursery and landscape industries and threatened C. micronesica K.D. Hill and C. taitungensis C.F. Shen, K.D. Hill, C.H. Tsou and C.J. Chen within their native habitats. The majority of the international cycad trade is dominated by Cycas revoluta Thunberg. We removed dense tomentum that characterizes C. revoluta cataphylls and excised intact leaf bases from stems of landscape C. revoluta plants to expose hidden surfaces. Additionally, we removed the root system from containers on nursery plants to reveal enclosed roots. All three organs were infested with cycad aulacaspis scale on tissue surfaces that cannot be detected during thorough visual inspection of intact plants. These unique concealed infestations allow this species to vector scale insects in a cryptic manner on cataphyll, stem, and root surfaces. This information lends support for a policy of strict prohibition of imported C. revoluta plants from countries known to have cycad aulacaspis scale infestations.
Development of a Branching Index for Evaluation of Peach Seedlings Using Interspecific Hybrids
Authors: Carrillo-Mendoza Omar , Sherman Wayne B. , Chaparro José X.
Published: February 2019

Trees without excessive branching are desirable for the reduction of pruning costs. Genetic diversity for less twiggy genotypes exists in peach and a branching index was developed for evaluation and selection of genotypes with reduced branching. The index is based on the number of total first-order branches and the number of second-order, third-order, and fourth-order branches measured on three randomly selected first-order branches. Index values were highly correlated (r2 ≈0.7) with the total number of branches over two growing seasons and served as a good predictor of branching patterns observed in the third growing season. Thus, the developed branching index is a useful tool in peach breeding, allowing for the early selection of trees with more desirable tree architecture.
Humic Substances Generally Ineffective in Improving Vegetable Crop Nutrient Uptake or Productivity
Authors: Hartz Timothy K. , Bottoms Thomas G.
Published: February 2019

Soil application of humic acid (HA), generally derived from leonardite shale, is a common practice in California vegetable production. Five commercial HA formulations were evaluated for their effects on soil microbial activity, seedling emergence, crop productivity, and nutrient uptake when applied to representative agricultural soils. Two soils differing in organic matter content (8 and 25 g·kg−1) were wetted to field capacity moisture content with solutions of water, nitrogen and phosphorus (P) fertilizer, HA, or fertilizer + HA and incubated aerobically at 25 °C. In the lower organic matter soil, a synergistic effect of fertilizer and HA was observed after 7 days of incubation on both microbial respiration and the amount of phospholipid fatty acids detected; these stimulatory effects were not observed in the higher organic matter soil. In a greenhouse pot study, the effects of HA on seedling emergence, dry mass accumulation, and P uptake of romaine lettuce (Lactuca sativae L.) were evaluated in four soils of low P availability; HA was applied to the soil at a rate simulating a field application of 2.2 kg·ha−1 a.i. HA had no significant effect on emergence rate or percentage, or P uptake, in any soil; plant dry mass was increased in one soil. Field trials were conducted in 2008 and 2009 evaluating the effects of pre-transplant soil application of HA at 1.1 or 3.4 kg·ha−1 a.i. on growth, nutrient uptake, and fruit yield of processing tomato (Lycopersicon esculentum Mill.). In neither year was macro- or micronutrient uptake increased with HA. Similarly, there was no significant HA effect on plant dry mass accumulation or fruit yield. We conclude that, at typical commercial application rates in representative field soils, HA is unlikely to significantly improve vegetable crop nutrient uptake or productivity.
Benzyladenine and Gibberellic Acid Application Prevents Abscisic Acid-induced Leaf Chlorosis in Pansy and Viola
Authors: Waterland Nicole L. , Finer John J. , Jones Michelle L.
Published: February 2019

Drought stress during the shipping and retailing of floriculture crops can reduce postproduction shelf life and marketability. The plant hormone abscisic acid (ABA) mediates drought stress responses by closing stomata and reducing water loss. Applications of exogenous s-ABA effectively reduce water loss and allow a variety of species to survive temporary periods of drought stress. Unfortunately, s-ABA application can also lead to leaf chlorosis, which reduces the overall quality of economically important bedding plant species, including Viola ×wittrockiana (pansy). The goal of this research was to determine how to prevent s-ABA-induced leaf chlorosis in pansy and a closely related species, Viola cornuta (viola). All concentrations of both spray (250 or 500 mg·L−1) and drench (125 or 250 mg·L−1) s-ABA applications induced leaf yellowing. Young plants at the plug stage and 11-cm finished plants with one to two open flowers were further evaluated to determine if the developmental stage of the plants influenced s-ABA effectiveness or the development of negative side effects. Both plugs and finished pansies and violas developed leaf chlorosis after s-ABA applications, but symptoms were generally more severe in finished plants. The individual application of benzyladenine (BA), gibberellic acid (GA4+7), or the ethylene perception inhibitor, 1-methylcyclopropene, before s-ABA application had no effect on the development of s-ABA-induced leaf chlorosis. However, applications of 5 or 10 mg·L−1 BA and GA4+7 as a mixture (BA + GA4+7) before a drench or spray application of s-ABA prevented leaf chlorosis. The application of s-ABA and BA + GA4+7 would allow floriculture crops to tolerate temporary periods of drought stress without any loss of postproduction quality.
Micropropagation and Reintroduction of the Endemic Mammillaria mathildae (Cactaceae) to Its Natural Habitat
Authors: García-Rubio Oscar , Malda-Barrera Guadalupe
Published: February 2019

A rapid shoot multiplication protocol was established for the endangered cactus Mammillaria mathildae to reintroduce it to its natural habitat. In vitro-germinated seedlings were used as the source of explants. Three explant sources (apical, lateral, and basal excised from in vitro-germinated seedlings) were tested. Shoot multiplication was induced in Murashige and Skoog (MS) medium supplemented with different 6-benzylaminopurine/indole-3-acetic acid (BA/IAA) combinations (0, 22.19, 44.39 and 0, 1.43, 2.85, 5.71, respectively). Explants developed abundant callus in the presence of any BA/IAA concentration, whereas hormone-free media produced 0.59 ± 0.11 new shoots (with a 41% callus development) from basal explants. Apical and lateral explants produced 1.14 ± 0.07 and 4.09 ± 0.13 new shoots, respectively, without callus generation. Plantlets originating from lateral explants developed a vigorous rooting system after 2 months growing on MS medium supplemented with 30 g·L−1 sucrose. Under greenhouse conditions, 98% of micropropagated M. mathildae survived. Plantlets were reintroduced in an experimental plot near to Juriquilla's wild population of M. mathildae; over 52% of the outplanted M. mathildae lot declined after 5 months. Water availability was associated with the decline of outplanted populations during the first month (43%).
Efficacy of Two Dithiopyr Formulations for Control of Smooth Crabgrass [Digitaria ischaemum (Schreb) Schreb. ex Muhl.] at Various Stages of Growth
Authors: Brosnan James T. , Breeden Gregory K. , McCullough Patrick E.
Published: February 2019

Although dithiopyr has been used for smooth crabgrass [Digitaria ischaemum (Schreb) Schreb. ex Muhl.] control for many years, data describing the efficacy of a new, water-based formulation of dithiopyr for smooth crabgrass control are limited. Research was conducted in Knoxville, TN, and Griffin, GA, evaluating water-based and wettable powder dithiopyr formulations at 0.56 and 0.43 kg·ha−1 for smooth crabgrass control when applied at the pre-emergence (PRE), one- to two-leaf (1LF), one- to two-tiller (1TL), and greater than three-tiller (3TL) stages of growth. These treatments were compared with quinclorac (0.84 kg·ha−1) applied at the same POST timings (i.e., 1LF, 1TL, and 3TL). When applied PRE, all dithiopyr treatments provided greater than 85% smooth crabgrass control at the end of the trial in both locations. At the 1LF stage, both rates and formulations of dithiopyr provided greater than 93% smooth crabgrass control at 4 weeks after application and greater than 77% at the end of the trial. Applied at the 1TL stage in Tennessee, no differences in smooth crabgrass control were detected between quinclorac and any dithiopyr treatment at the end of the trial; when applied in Georgia at the 1TL stage, quinclorac provided greater smooth crabgrass control at the end of the trial than either rate or formulation of dithiopyr. Although no differences were detected between any dithiopyr treatment and quinclorac applied at the 3TL stage in Tennessee, smooth crabgrass control at the end of the trial measured less than 70% for all treatments. At the end of the trial in Georgia, smooth crabgrass control with quinclorac (91%) was greater than both formulations of dithiopyr. These findings suggest that both the wettable powder and water-based formulations of dithiopyr can be used to effectively control smooth crabgrass at the PRE and 1LF stages of growth, but quinclorac should be selected over dithiopyr for control of tillering smooth crabgrass plants. Turfgrass managers should implement smooth crabgrass control measures at PRE and 1LF timings, because erratic responses can be observed with both dithiopyr and quinclorac applications to smooth crabgrass after tillering. Chemical names used: dithiopyr (S,S-dimethyl 2-(difluoromethyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyridinedicarbothioate); quinclorac (3,7-dichloro-8-quinolinecarboxylic acid).
In Vitro Adventitious Rooting of Carrizo Citrange Microshoots
Authors: Montoliu Almudena , Gómez-Cadenas Aurelio , Pérez-Clemente Rosa M.
Published: February 2019

The objective of this work was to develop an efficient in vitro rooting protocol for one of the most commercially used citrus rootstocks in Spain, Carrizo citrange (Citrus sinensis L. Osbeck × Poncirus trifoliata L. Raf.). Single-node cuttings taken from greenhouse-grown plants were cultured in petri dishes containing basal Murashige and Skoog medium. Shoots from nodal stem segments were excised and cultured in a multiplication medium (basal medium supplemented with 1.8 μM 6-benzylaminopurine) to promote the development of axillary buds. Individual shoots (15 mm long) were treated with different hormones at several concentrations for root induction evaluations. The addition of activated charcoal (AC) to the culture medium was also explored. The addition of auxins to the culture medium enhanced rooting percentage. Optimal results were obtained when 1-naphthalene acetic acid (10.8 μM) and gibberellic acid (0.3 μM) were added to the culture medium. The addition of AC to the rooting medium resulted in negative effects on the percentage of rooted shoots but had a positive effect on number of roots per rooted shoot. Chemical names used: activated charcoal (AC); 6-benzylaminopurine (BA); 1-naphthalene acetic acid (NAA); gibberellic acid (GA3); indole-3-butyric acid (IBA)
A “Green” Extraction Protocol to Recover Red Pigments from Hot Capsicum Fruit
Authors: Richins Richard D. , Hernandez Laura , Dungan Barry , Hambly Shane , Holguin F. Omar , O'Connell Mary A.
Published: February 2019

Plant pigments represent a source of non-toxic compounds that are used as food or cosmetic coloring agents. Red-fruited varieties of Capsicum annuum can be extracted to isolate the red-colored xanthophylls, capsanthin, and capsorubin. Common commercial processes for this extraction use hexane as the extracting solvent and mild or no heat varieties of Capsicum. In this report, we describe a process for efficient extraction of these red pigments using green chemistry: CO2 supercritical fluid extraction and trapping the pigments in ethanol. Furthermore, we demonstrate that this method can be performed on hot or pungent Capsicum fruit and the resulting pigment sample has very low levels of capsaicinoids, 1 to 2 ppm. This process then can reduce the use of hazardous solvents and expand the type of fruit that can be used for the extraction of red pigments.
Exploring Dimensions of Attitudes Toward Horticultural Activities
Authors: Chen Hui-Mei , Tu Hung-Ming , Ho Chaang-Iuan
Published: February 2019

The main purpose of this research was to explore individuals' attitudes toward horticultural activities. The research was conducted in two stages. First, open-ended interviews were used to conceptualize attitudes toward horticultural activities, and seven themes and several subthemes of attitudes were induced. Based on the results, a questionnaire was then designed and a quantitative survey was conducted to identify the dimensions of attitudes toward horticultural activities and their interrelationships. Five dimensions of attitudes toward horticultural activities were extracted: increasing positive mood, improving the environment, leisure belief, improving social relationships, and escaping. These dimensions of attitudes toward horticultural activities had activity-based attributes that differed to some extent from those of general leisure. The dimension of improving the environment was particularly salient for horticultural activities. Propositions and recommendations to stimulate future research about developing a valid measurement instrument are offered.
Isolation and Characterization of 13 Microsatellite Loci from Pedicularis rex (lousewort)
Authors: Huang Pan-Hui , Yu Wen-Bin , Yang Jun-Bo , Wang Hong , Lu Lu
Published: February 2019

Pedicularis rex C. B. Clarke ex Maxim., an endemic species with potential horticultural traits from Himalaya, has a unique cup-like petiole structure and highly infraspecific floral variation among members of the lousewort genus (Orobanchaceae). We developed 13 microsatellite markers from three microsatellite-enriched libraries (AG, AC, and AAG) of P. rex with a modified biotin–streptavidin capture technique. Polymorphism of each locus was assessed in 22 individuals with representation of five populations of P. rex. Number of alleles per locus (A) ranged from two to seven with an average of 4.38. The observed and expected heterozygosities varied from 0.03 to 0.86 and 0.45 to 0.84, respectively. Additionally, among the 13 identified microsatellite markers, 11 of them were successfully amplified in species P. thamnophila, and five of them showed polymorphisms. This study may provide important information for further investigation on the population genetics, introduction, and acclimatization of P. rex and its congeners.
Self-compatibility Evaluation in Almond: Strategies, Achievements, and Failures
Authors: Socias i Company Rafel , Fernández i Martí Àngel , Kodad Ossama , Alonso José M.
Published: February 2019

Several approaches have been used in evaluating self-compatibility in almond. These include fruit set after self-pollination and bagging, pollen tube growth, and the more recent Sf allele identification by molecular markers and gene sequencing. However, none of these methods have given fully reliable results because they all show advantages and limitations. Pollen contamination may distort pollination results as well as inaccuracies during fruit setting operations. Factors other than self-compatibility such as inbreeding may affect fruit set and pollen tube growth. Detection of S alleles by RNase activity and polymerase chain reaction analysis by consensus primers has not always been conclusive. The differential phenotypic expression of the Sfa and the Sfi alleles has revealed that the presence of the Sf allele is not the only requirement for self-compatibility expression in almond. As a consequence, the coding region of the Sf allele may not be the sole factor involved in that expression, which may be caused by modifier genes outside this region. Missequencing of alleles has also created confusion for allele identification. Thus, self-compatibility evaluation in almond must involve a better knowledge of the plant material as a whole, and not only of its genotype. All factors involved in setting a commercial crop in conditions of solid plantings of a single cultivar must be put together to evaluate almond self-compatibility. This approach is fundamental for the understanding of self-compatibility in almond and for the evaluation of the new selections in a breeding program.
Impact of Kaolin Particle Film and Water Deficit on Wine Grape Water Use Efficiency and Plant Water Relations
Authors: Glenn D. Michael , Cooley Nicola , Walker Rob , Clingeleffer Peter , Shellie Krista
Published: February 2019

Water use efficiency (WUE) and response of grape vines (Vitis vinifera L. cvs. ‘Cabernet Sauvignon’, ‘Merlot’, and ‘Viognier’) to a particle film treatment (PFT) under varying levels of applied water were evaluated in Victoria, Australia, and southwestern Idaho. Vines that received the least amount of water had the warmest canopy or leaf surface temperature and the lowest (more negative) leaf water potential, stomatal conductance (gS), transpiration (E), and photosynthesis (A). Vines with plus-PFT had cooler leaf and canopy temperature than non-PFT vines; however, temperature difference resulting from irrigation was greater than that resulting from PFT. In well-watered vines, particle film application increased leaf water potential and lowered gS. Point-in-time measurements of WUE (A/E) and gS did not consistently correspond with seasonal estimates of WUE based on carbon isotope discrimination of leaf or shoot tissue. The response of vines with particle film to undergo stomatal closure and increase leaf water potential conserved water and enhanced WUE under non-limiting soil moisture conditions and the magnitude of response differed according to cultivar.
Quality Attributes Limiting Snap Bean (Phaseolus vulgaris L.) Postharvest Life at Chilling and Non-chilling Temperatures
Authors: Proulx Emilie , Yagiz Yavuz , Cecilia M. , Nunes N. , Emond Jean-Pierre
Published: February 2019

‘Opus’ and ‘Leon’ snap beans were harvested, hydrocooled, held for 2 to 7 days at five temperatures and evaluated for quality attributes. The objectives of this work were to obtain quality curves at chilling and non-chilling temperatures, identify for each temperature which quality attributes limit snap beans marketability, and determine the remaining compositional value at the point the snap beans had reached the minimum acceptable quality for sale. Results from this study showed that temperature had a significant effect on the shelf life and overall quality of snap bean. Snap beans stored at temperatures higher than 10 °C were less green, softer and more shriveled, had higher weight loss, and lower acidity, soluble solids, ascorbic acid, and chlorophylls contents than those stored at lower temperatures. When stored at 1, 5, and 10 °C, ‘Leon’ snap beans developed chilling injury (CI), whereas no visual symptoms were noticeable in ‘Opus’ snap beans. Although CI might have indirectly affected the quality of ‘Leon’ snap beans, it was not considered a sensory quality-limiting factor. Overall, weight loss was the first non-sensory quality attribute to reach the limit of acceptability, whereas firmness was the first sensory quality attribute, followed by color, to reach the limit of acceptability and therefore limited the shelf life of ‘Opus’ and ‘Leon’ snap beans cultivars. As a result of excessive water loss and accelerated softening, shelf life of both snap bean cultivars was relatively short, ranging from 1 to 3.5 days, depending on the temperature and cultivar. Furthermore, the compositional value was considerably reduced at the point of poor sensory quality. The high weight loss obtained for beans stored at all temperatures suggests that the use of a film wrap may help create a high relative humidity and therefore reduce water loss, maintain better overall quality, and extend the shelf life of snap beans. Overall, maximum shelf life and best quality were obtained when ‘Opus’ and ‘Leon’ snap beans were stored at 10 °C.
Standardized Plant Disease Evaluations Will Enhance Resistance Gene Discovery
Authors: Postman Joseph , Volk Gayle , Aldwinckle Herb
Published: February 2019

Gene discovery and marker development using DNA-based tools require plant populations with well-documented phenotypes. If dissimilar phenotype evaluation methods or data scoring techniques are used with different crops, or at different laboratories for the same crops, then data mining for genetic marker correlations is challenging. For example, apples and pears may share many of the same disease resistance genes. Fire blight resistance evaluations for apples often use a scale of 1 to 5 and pear evaluations use a scale of 1 to 9. In some reports, a low number means low susceptibility and in other reports, a low number means low resistance. Other disease evaluations rate resistance as greater than or less than a well-documented standard cultivar. Environment, pathogen isolate, and whether disease ratings are the result of natural infection or artificial inoculation also have a strong impact on disease resistance ratings. Before a wider set of disease resistance phenotype data can be correlated with genetic data, rating scales must be standardized and the evaluation environment must be taken into account. Standardizing the recording of disease resistance data in plant phenotype databases will improve the ability to correlate these data with genomic data.
Mechanical String Thinner Reduces Crop Load at Variable Stages of Bloom Development of Peach and Nectarine Trees
Authors: Baugher T. Auxt , Ellis K. , Remcheck J. , Lesser K. , Schupp J. , Winzeler E. , Reichard K.
Published: February 2019

Thinning of blossoms or fruitlets is a labor-intensive requirement in the production of peach and nectarine (Prunus persica) fruit of optimum size and quality. Prior research conducted by the authors on string blossom thinners for managing peach tree crop load demonstrated that this new technology reduces labor requirement and improves fruit size. The research reported in the current article was conducted over 2 years on ‘Sugar Giant’ peach and ‘Arctic Sweet’ nectarine to evaluate string blossom thinner efficacy at variable stages of bloom development ranging from pink to petal fall. Blossom removal at the pink stage of bloom development was lower than at other stages in 2008; however, a 150-rpm versus 120-rpm spindle rotation speed resulted in blossom removal similar to the 80% full bloom (FB) treatment in 2009. Blossom removal at the petal fall stage was similar to the open bloom stage with the exception of the 2009 ‘Sugar Giant’ trial, in which blossom removal was higher at 80% FB. Flower density and fruit set of the bloom stage compared with hand-thinned control treatments followed a similar trend with the exception that there were fewer differences in 2009 and in lower canopy regions. Follow-up hand thinning time was reduced by all string thinning/year combinations except ‘Arctic Sweet’ at pink in 2008 and 2009 and at petal fall in 2009. The best treatments reduced follow-up hand thinning time compared with green fruit hand thinning alone by 51% and 41% for ‘Sugar Giant’ and by 42% and 22% for ‘Arctic Sweet’ in Years 1 and 2, respectively. In 2008, the percentage of fruit in the “7.0 cm or greater” size category was increased by all bloom stage treatments in both cultivars. The 2009 size distribution of ‘Arctic Sweet’ fruit was unaffected, but the percentage of ‘Sugar Giant’ fruit in higher market value size categories was increased by the 80% FB and higher rpm pink treatments. Savings in hand thinning time and/or increases in fruit size in both years associated with the bloom stage treatments resulted in a net positive impact of $123/ha to 1368/ha compared with hand thinning alone.
Evaluating Hawaii-grown Papaya for Resistance to Internal Yellowing Disease Caused by Enterobacter cloacae
Authors: Nishijima Kate A. , Wall Marisa M. , Fitch Maureen M. , Sugiyama Lionel S. , Keith Ronald C. , Nishijima Wayne T.
Published: February 2019

Papaya (Carica papaya L.) cultivars and breeding lines were evaluated for resistance to Enterobacter cloacae (Jordan) Hormaeche & Edwards, the bacterial causal agent of internal yellowing disease (IY), using a range of concentrations of the bacterium. Linear regression analysis was performed and IY incidence was positively correlated with increasing inoculum concentrations for susceptible cultivars Kapoho Solo and Laie Gold but not for resistant cultivars or lines. It was determined that the inoculum concentration of 9 to 10 Log10 colony-forming units per milliliter (cfu/mL) was able to reliably differentiate resistant and susceptible papaya germplasm. Red-fleshed cultivars SunUp and Sunrise were the most resistant papaya groups evaluated at this dose concentration. Yellow-fleshed cultivars, Kapoho Solo and Laie Gold, were susceptible to E. cloacae. ‘Rainbow’, an F1 hybrid between ‘SunUp’ and ‘Kapoho Solo’ that is yellow-fleshed, was moderately resistant to E. cloacae, exhibiting limited symptoms of the disease. Yellow-fleshed I-Rb F5/F6, an advanced inbred line derived from ‘Rainbow’, is resistant and offers the potential of improving resistance of yellow-fleshed commercial cultivars. A colorimeter was used to objectively measure internal flesh color and distinguish between infected and non-infected tissue in red- and yellow-fleshed papayas using L*C*H* color space analysis. Symptomatic tissue (72.4 and 79.0°) had higher hue angle means than non-symptomatic tissue (62.8 and 75.0°) for all cultivars or lines in red- and yellow-fleshed papayas, respectively. Yellow (“Y”) hue color also distinguished infected tissue from non-infected tissue. Symptomatic tissue that had Y hue color resulted in 79 to 81° hue angle means among red- or yellow-fleshed papayas. Our results demonstrated the usefulness of colorimetry to help detect infected papaya tissue. In surveys of naturally infected papaya, high populations (8.57 × 107 cfu/g) of E. cloacae were recovered in infected fruit of ‘Kapoho Solo’ and represent a food safety concern for fresh and processed papaya. In isolations from inoculated fruits, we observed decreases of ≈1 to 2 Log10 cfu/g in final bacterial populations when high-dose range inoculum concentrations (9 to 12 Log10 cfu/mL) were used. This dose range may represent a saturation range for E. cloacae inoculation.
Performance of Mechanical Thinners for Bloom or Green Fruit Thinning in Peaches
Authors: Miller Stephen S. , Schupp James R. , Baugher Tara A. , Wolford Scott D.
Published: February 2019

Peach (Prunus persica L. Batsch) thinning is a costly and time-consuming but necessary practice to produce a crop of marketable size fruit. A number of mechanical devices and methods have been developed and evaluated to reduce the cost and time required for hand thinning peach. This report provides additional evidence that a Darwin string thinner can effectively thin peach at bloom and a spiked drum shaker can thin at bloom or at the green fruit (pit hardening) stage. Five trials were conducted over 2 years in grower orchards with trees trained to a perpendicular V system. A Darwin string thinner at 60% to 80% full bloom (FB) reduced crop load (fruit/cm2 limb cross-sectional area) on scaffold limbs by 21% to 50% compared with a hand-thinned control. At the 60% FB stage, a USDA-designed double-spiked drum shaker reduced crop load by 27% and in another trial, a USDA prototype single-drum shaker reduced crop load by 9%. Across all trials, the spiked drum shakers (single or double units) removed an average of 37% of the green fruit. All mechanical devices reduced the time required for follow-up hand thinning. Follow-up hand-thinning costs (US$/ha) were reduced an average of 27% by mechanical thinning devices over hand-thinned control trees. Fruit size was increased over hand-thinned controls by mechanical thinning in most, but not all, trials. A combined treatment of the Darwin string thinner at bloom followed by a drum shaker (single or double unit) at the green fruit stage produced the greatest net economic impact in a number of the trials. Despite overthinning in some trials, the mechanical thinning devices described provide a potential alternative to hand thinning alone in peach production.
Evaluation of Irrigation Methods for Highbush Blueberry—I. Growth and Water Requirements of Young Plants
Authors: Bryla David R. , Gartung Jim L. , Strik Bernadine C.
Published: February 2019

A study was conducted in a new field of northern highbush blueberry (Vaccinium corymbosum L. ‘Elliott’) to determine the effects of different irrigation methods on growth and water requirements of uncropped plants during the first 2 years after planting. The plants were grown on mulched, raised beds and irrigated by sprinklers, microsprays, or drip at a rate of 50%, 100%, and 150% of the estimated crop evapotranspiration (ETc) requirement. After 2 years, drip irrigation at 100% ETc produced the most growth among the irrigation methods with at least 42% less water than needed for maximum growth with microsprays and 56% less water than needed with sprinklers. Drip irrigation also maintained higher soil water content in the vicinity of the roots than the other methods but reduced growth when plants were over-irrigated at 150% ETc. Only 570 mm of irrigation water, or the equivalent of 1320 L per plant, was required over two seasons to reach maximum total plant dry weight with drip, whereas 980 mm or more water was needed with sprinklers and microsprays. Consequently, irrigation water use efficiency (defined as the difference in plant biomass produced under irrigated and rain-fed conditions divided by the total amount of irrigation water applied) was significantly higher with drip than with the other irrigation methods, averaging 0.41 g of total dry weight per liter of drip irrigation. In terms of both growth and water use, drip irrigation was the best and most efficient method to establish the plants.