Journal of Applied Horticulture Selected Contents of Year

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Benyamin Lakitan1, Laily Ilman Widuri2, and Mei Meihana2,3

1College of Agriculture, Universitas Sriwijaya, Inderalaya 30662, Indonesia. 2Graduate School, Universitas Sriwijaya, Palembang 30139, Indonesia. 3STIPER Sriwigama, Palembang 30137, Indonesia

Key words: trifoliate leaf, leaflet, estimation model, growth analysis, leaf expansion

Journal of Applied Horticulture, 2017, volume 19, issue 1, pages 15-21.

Abstract: Non-destructive measurement of leaf area (LA) is preferred in growth analysis and plant physiological studies. Many regression-based models have been developed for estimating LA using leaf length (L), leaf width (W), or imaginary rectangle of L x W (LW) as predictor or independent variable. Objective of this study was to develop and validate appropriate regression models for estimating snap bean trifoliate LA using easily measured L, W, or calculated LW. Snap bean used in this research was PV072 cultivar. Trifoliate-leaf samples were purposively collected from different individual plants, to represent wide range of leaf sizes, from the smallest leaf with fully open blade to the largest available leaf. Snap bean trifoliate leaf consists of three leaflets. The sampled leaves were alternately divided into two subgroups, based on length of terminal leaflet, for developing and validating LA estimation models. Linear, quadratic, and power regressions were evaluated for their appropriateness to be used for estimating LA. Intercept (a) was forced to zero to make the models more geometrically realistic. Results of this research indicated that: (1) zero-intercept quadratic and power regression models performed well for length of leaflet (Lt) or width of leaflet (Wt) was used as predictor, whereas zero-intercept linear model was appropriate and geometrically-sound if imaginary rectangular Lt x Wt (LtWt) was used for estimating surface area of both terminal and side leaflets (LtA); (2) for a practical, fast, and accurate estimation of LA, LtWt of terminal leaflet was the recommended option among other single or combination of predictors; and (3) recommended empirical model for LA estimation of snap bean trifoliate leaf is LA = 1.5198 LtWt.
K. Ohta

Department of Agricultural and Forest Sciences, Shimane University, Matsue, Shimane 690-8504, Japan.

Key words: Flesh weight, fruit number, fruit weight, locular gel, Solanum lycopersicum

Journal of Applied Horticulture, 2017, volume 19, issue 1, pages 22-28.

Abstract: We investigated changes in the incidence of fruit cracking, yield, number, and characteristics of cherry tomato (Solanum lycopersicum L.) in Japan over a 20-year period. Ten cultivars released in Japan during this period were compared in a short-term experiment conducted from fall through winter in hydroponics. The incidence of fruit cracking in cherry tomato cultivars decreased gradually with year of release from 1987-2009. The incidence of fruit cracking was negative correlated with fruit yield and number among the 10 cultivars tested. In regard to fruit characteristics, the incidence of fruit cracking was negatively correlated with the fruit weight, the ratio of flesh weight to locular gel weight (F/G), and thickness of exocarp and mesocarp, but not with the flesh weight, soluble solid content, or firmness of exocarp and mesocarp among the 10 cultivars tested. These results indicated that, by breeding in cherry tomato cultivars released in Japan over the past two decades, the decreased incidence of fruit cracking was related to the increase in the fruit yield and number per plant, and to the increase in fruit weight and F/G, in association with an increase in the total volume of water inflow into fruits.
A.N. Niyokuri1, 2, S. Nyalala2 and Mariam Mwangi2

1College of Agriculture, Animal Sciences and Veterinary Medicine (CAVM), University of Rwanda. P.O. Box 210 Musanze, Rwanda. 2Department of Crops, Horticulture and Soils, Egerton University. P. O. Box 536-20115, Egerton, Kenya

Key words: Bioslurry, carnation, plant biostimulant, vase life, flower quality, flower yield

Journal of Applied Horticulture, 2017, volume 19, issue 1, pages 29-34.

Abstract: Two greenhouse experiments were conducted in Finlays, Lemotit Flower Farm, Kenya to determine the effect of bioslurry and plant biostimulant Hicure on yield, quality and vase life of carnation. The experiments were laid in split plot embedded in a randomized complete block design with three replications. Four levels of bioslurry: 0, 0.125, 0.25 and 0.5 L m-2 were applied in the main plot while four levels of Hicure: 0, 2.0, 2.5 and 3.0 L ha-1 were used in the sub-plot. Results showed that bioslurry or plant biostimulant did not have a significant effect on carnation�s flower yield, weight, flower stem length and flower stem diameter. However, the interaction of bioslurry and plant biostimulant particularly at the rate of 0.5 L m-2 and 3 L ha-1 significantly improved the flower stem length by 1.11 cm as compared to control. The application of bioslurry significantly improved the flower head size in second trial from 21.09 mm in control to 21.68 mm, 21.81mm and 21.90 mm for the carnation�s flower head diameter and from 40.34 mm in control to 40.96mm, 40.97 mm and 40.88 mm for the carnation�s flower head length respectively for the rate of 0.125, 0.25 and 0.5 L m-2. The plant biostimulant Hicure significantly improved the flower head diameter from 22.12mm in control to 22.32 mm, 22.30mm and 22.40mm by respective application of Hicure at the rate of 2.0, 2.5 and 3.0 L ha-1 during first trial. Their interaction also improved the flower head length in second trial. Application of bioslurry had no significant effect on the vase life while plant biostimulant at the rates of 2.0, 2.5 and 3.0L ha-1 significantly reduced the vase life by two days in first trial and one day in second trial. It was concluded that application of bioslurry at the rate of 0.5 L m-2 and plant biostimulant Hicure at the rate 3 L ha-1 can therefore, be adopted for improvement of carnation quality parameters such as stem length and flower head size.
Peter Jeranyama1, Jenna Sicuranza2, Harvey J.M. Hou3 and Carolyn DeMoranville1

1University of Massachusetts Amherst, Cranberry Experiment Station, 1 State Bog Rd, P.O. Box 569, East Wareham, MA 02538. 2Seed Savers Exchange, 3094 North Winn Road, Decorah, Iowa 52101. 3Alabama State University, Department of Physical Sciences, 915 S. Jackson St. Montgomery, AL 36104.

Key words: Yellow vine, cranberry, Vaccinium macrocarpon, stress, chlorophyll, gas exchange, nutrient

Journal of Applied Horticulture, 2017, volume 19, issue 1, pages 3-7.

Abstract: Yellow vine (YV) on cranberry (Vaccinium macrocarpon Ait.) is a symptom of stress that might reduce upright net photosynthetic carbon assimilation (A) through both, stomatal effects, which reduce the internal CO2 concentration (Ci), and nonstomatal factors. This study evaluated the shade effects on reversing the effects of YV symptoms in chlorophyll and nutrient content, and uprights gas exchange. Shaded vines were affected in the same way as unshaded yellow vines and their net photosynthetic carbon assimilation was not affected by stomatal activity in contrast with the normal green vines. However, A was not limited by stomatal activity ? 250 mmol m-2 s-1. Chlorophyll a concentration was positively correlated with A (r = 0.53 P? 0.05), shaded and YV had significantly lower total chlorophyll concentration relative to normal vines. Chlorophyll b was less affected by YV symptoms. Plant tissue were collected in autumn and analyzed for individual nutrient composition. Manganese levels were excessive in all samples; this was especially true for yellow vines, suggesting that the yellow vines may be under more water stress. Shading yellow vines did not change their nutrient composition relative to unshaded yellow vines. It is plausible that excess water on the bog is the major cause of the yellow vine as growers have a cultural practice of applying 25 mm of irrigation water a week regardless of the evaporative demand or field capacity.
Amira Sh. Soliman1 and Nermeen T. Shanan2

1Natural Resources Department, Institute of African Research and Studies, Cairo University, Giza, Egypt. 2Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Giza, Egypt.

Key words: Lagerstroemia indica, foliar applications, moringa leaves extract, sea salt stress, inflorescence characteristics, antioxidant enzymes.

Journal of Applied Horticulture, 2017, volume 19, issue 1, pages 35-45.

Abstract: A pot experiment was conducted during 2014 and 2015 seasons in completely randomized factorial design to determine the effect of natural extracts foliar spray of Moringa leaves extract (1:30), humic acid (10%), seaweed (2%), Hogland nutrient solution and tap water as control on growth characteristics (plant height, stem diameter, number of leaves/plant, number of branches/plant, root length, and total dry weight of plant parts (roots, shoots and flowers), floral and chemical characteristics of Lagerstroemia indica grown at various sea salt concentrations (0, 3.12, 6.25 and, 9.37 dS/m) showed that by increasing sea salt concentrations, all growth characteristics, inflorescence number/plant and, inflorescence diameter decreased significantly, while, the number of days to inflorescence increased. Total chlorophylls, carotenoid contents, total carbohydrates and N, P, K%. Meanwhile, proline content, total soluble phenols, Na, Ca, and antioxidant enzymes (catalase, superoxide dismutase and peroxidase) increased at the high level of salinity (9.37 dS/m). The usage of the Moringa leaf extract was significantly improved growth, inflorescence, as well as chemical characteristics, but also, decreased significantly Na under the adverse conditions of the studied sea salt stress. Moringa leaf extract could promote and protect crape myrtle plants against injuries by sea salt stress can be substitute inorganic or chemical fertilizer being safe and cheap.
Taycir Grati, Rachid Hellali, Salah Rezgui and Mehdi Ben Mimoun

NAT.43 Avenue Charles Nicole, City Mahrajene, 1082, Tunis, ISEP=BG 49 Avenue 13 Aot Choutrana II, 2036 Soukra. Tunisia.

Key words: Citrus orchard; hedgerow orchard; radiation; high density planting, pruning, chlorophyll

Journal of Applied Horticulture, 2017, volume 19, issue 1, pages 8-14.

Abstract: The experiment consisted in hedging citrus trees of the variety Washington Navel with a density of planting of 873 plants/ha. The hedge was 2.65 m high, 0.5 m wide on the upper part and 1.5 m on the lower part forming 10 degrees angle to the vertical and NE/SW orientation. The control tree was cut to a ball shape. Considering mean values of three years, hedging showed a high vegetative stretching (7.20 cm) while the control tree had a lengthening of 4.18 cm, with a growth rate of the spring shoots of 6.80 mm and 4.29 mm per day, respectively. As well, a larger spring leaf area was noted as compared to the control tree. This area was 366.55 cm2 against 124.22 cm2 by branch, respectively. In spite of a more severe pruning in the treatment, the fruit yield was near to that of the control (9.12 kg/tree) with a density of 873 trees/ha. No significant difference was noted for the total amount of chlorophyll between both sides of the hedge (South/East and North/West) for the non-bearing shoots (1.75 and 1.51 mg. g-1 fresh weight, respectively) and bearing ones (1.57 and 1.51 mg/g fresh weight) contrarily to the control (non-bearing shoots 1.2 and 1.57 mg g-1 fresh weight; bearing shoots 1.97 and 1.35 mg. g-1 fresh weight). All stages of maturation occurred earlier in the treatment.
S. Bartolini, C. Iacona, D. Remorini and R. Viti

Scuola Superiore Sant Anna, Institute of Life Science, Pisa, Italy. Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.

Key words: Prunus armeniaca L., dormancy, xylogenesis, flowering, fruiting

Journal of Applied Horticulture, 2016, volume 18, issue 3, pages 171-177.

Abstract: The aim of this research was to study the involvement of weather conditions and the influence of two Prunus rootstocks (Myrabolan 29/C and apricot Seedling) on flower bud biology of Pisana (Prunus armeniaca L.), one of the most appreciated Italian apricot cultivar, grown in a Mediterranean agro-climatic environment. Anatomical investigations on xylem differentiation within flower buds and biological observations on flowering as well as fruiting were carried out over two consecutive growth seasons. These years were characterized by different weather conditions due to temperatures and rainfall events which influenced the chilling accumulation, blooming time and xylogenesis process. The onset of xylogenesis within flower buds was conditioned by summer temperatures and water availability. The two rootstocks commonly used in apricot, Myrabolan 29/C and apricot Seedling, did not affect the flowering and fruit-set rate of the grafted cultivar. Nevertheless, differences in progressive differentiation of the secondary thickness of procambial cells in xylem vessels were observed.
M. Olszewski, B. Snyder and J. Pils

Department of Landscape Architecture and Horticulture, Temple University, 580 Meetinghouse Rd., Ambler, PA 19002. Director of Research and Development, Aquatrols Corporation, Paulsboro, NJ 08066.

Key words: Growing media, wetting agent, hydrophobicity, peat, bark, mix manufacturers

Journal of Applied Horticulture, 2016, volume 18, issue 3, pages 178-182.

Abstract: Surfactant formulations consisting of proprietary blends containing sulfonic acid ester ethylene oxide/propylene oxide block copolymer blend (ACA3204-R and ACA3204-P); sulfonic acid ester ethylene oxide/propylene oxide block copolymer blend with polyethylene glycol addition (ACA3204-2a), and ethoxylated alkylphenol (ACA160) were tested for wettability of peat-based substrates and for relative phytotoxicity. Substrate incorporation rates used in this study were 116 mL m-3 (a low recommended rate), 232 ml m-3 (a moderate recommended rate), and 464 ml m-3 (a supra-optimal rate). After a third wetting cycle, those substrates incorporated with ACA3204-R, ACA3204-P, or ACA160 at 232 ml m-3 had higher wettability ratings than the Pro-Mix HP control (Premier Horticulture Inc., Quakertown, PA). There were no differences in shoot dry weight (SDW) or visual root health rating (VRHR) among treatment groups of impatiens (Impatiens walleriana) compared to the control For pansy (Viola wittrockiana), Pro-Mix-HP control-grown plants had higher SDW (0.8632 g shoot-1) than ACA3204-R at 464 mLm-3 (SDW = 0.6266 g shoot-1) but SDWs for ACA3204-P, ACA3204-2a and ACA160 were similar to the control at all rates. Compared to the control, pansy VRHRs declined at 464 ml m-3 for all surfactants except for ACA160. In general, higher rates of surfactant increased mean days to 50% germination (DX; an inverse measure of germination rate) compared to distilled water control for pansy but this effect was less pronounced for impatiens. There appeared to be a stimulatory seedling effect on mean pansy root length for ACA3204-R and ACA3204-P (rates = 300-1200 ppm) and for ACA3204-2a (rates = 600-1200 ppm). In conclusion, surfactant formulations ACA3204-R, ACA3204-P, ACA3204-2a, and ACA160 were comparatively non-phytotoxic at moderate rates of substrate incorporation (mature plant growth) but laboratory seed germination was affected by low concentrations. ACA3204-R had similar wettability rating to that of ACA160 following the third wetting cycle. Further testing with additional plant species and substrates would aide in evaluating the usefulness of newer horticultural surfactants.
J. Dolezalova, M. Koudela, L. Augustinova and M. Dubsk

Department of Horticulture, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic. Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Pr?honice, Czech Republic.

Key words: Lactuca sativa L. var. capitata L., seedling, growth, water deficit, brassinolide, vegetable, stimulant

Journal of Applied Horticulture, 2016, volume 18, issue 3, pages 183-186.

Abstract: Water deficit is one of the most adverse factors for plant growth and productivity. The experiments were conducted to investigate the influence of synthetic brassinolide analogue at concentrations 100 nmol.L-1 , 1 nmol.L-1 , 0.01 nmol.L-1 and 0 nmol.L-1 on lettce seedling grown at two moisture levels (reduced, control). The plants were cultivated in growth chamber under day / night temperature of 20 oC/15 oC. The total quantities of irrigation water during the experiment: reduced - 28 mm; control - 39 mm. The seedlings of two butter head lettuce cultivars (cv. Mars and cv. Marsalus) were sprayed to foliage at juvenile stage of growth. The plant parameters (length, fresh weight of shoots and roots) and dry matter content were measured on 21st and 28th day after sowing. Significantly higher values of the average fresh weight and length of aboveground part and roots were measured on 28th day for the cultivar Marsalus treated with brassinosteroide analogue at concentration 1 nmol.L-1 in conditions with reduced irrigation. The results showed that treatment of plants in the initial stage of the development with 1 nmol.L-1 solution can be used to limit the consequences of reduced moisture conditions. Prior to use the most effective concentration should be taken into account which parameter of plant is expected to be changed and also the varying sensitivity of the cultivars to the treatment.
Kirath Singh, Gyanalok Das, Kundansingh R Jadhao, Gyana Ranjan Rout

Department of Agril. Biotechnology,College of Agriculture, AICRP Medicinal & Aromatic Plants, Orissa University of Agriculture & Technology, Bhubaneswar- 3, Odisha,

Key words: Piper spp, Piperaceae, HPTLC analysis, Piperine content, ISSR marker, genetic diversity analysis.

Journal of Applied Horticulture, 2016, volume 18, issue 3, pages 187-194.

Abstract: Phytochemical and molecular characterization of Piper species was investigated. There was a wide variation of the active compounds present in leaf and fruits of different Piper species/accessions. Among the two active compounds, piperine-1 content was more in P. chaba fruit and Piperine -2 in P. nigrum fruit as compared with other species. Inter Simple Sequence Repeats (ISSR) marker was also used to analyze the genetic variation between the species / accession of Piper species. The phylogenetic analysis generated by ISSR marker was divided into two major groups with 47% similarity. First major group is only one species (i.e. Piper spp. Accession -1) and also morphologically distinct from other seven species. The second groups are divided into two minor groups. Piper betle var. Godi Balunga and Piper betle var. Astarangi Balunga are grouped together with 100 % similarity at genetic level, whereas, Piper betle var. Utkal Sudhama having 97 % similarity with Piper betle var. Godi Balunga and Piper betle var. Astarangi Balunga. Both phytochemical and molecular marker was showed significant variation among and between species/accessions. This study will help for the breeding program in Piper .
Ustun Sahin, Yasemin Kuslu, Fatih M. Kiziloglu and Talip Cakmakci

Ataturk University, Faculty of Agriculture, Department of Agricultural Structures and Irrigation, 25240 Erzurum, Turkey. Yuzuncu Y?l University, Faculty of Agriculture, Department of Biosystem Engineering, 65080, Van, Turkey.

Key words: Antioxidant activity, marketable yield, mineral content, total phenolics, water productivity

Journal of Applied Horticulture, 2016, volume 18, issue 3, pages 195-202.

Abstract: Water stress under reduced irrigation conditions affect plant physiology and hence yield and crop quality. Moreover, high altitude climatic conditions can significantly influence plant physiology. Therefore, a two year field study was conducted to determine the effects of different irrigation quantities on plant growth (leaf number, stem diameter, plant diameter and height), marketable yield, water use and crop quality attributes (mineral content, total phenolics and antioxidant activity) of drip-irrigated lettuce in a semi-arid region with a high altitude. A randomized complete block design was used for testing of different irrigation quantities replicated three times. Different irrigation quantities were adjusted considering 100 (I1), 85 (I2) and 70% (I3) of evaporated water from a Class A pan. Lettuce evapotranspiration was the highest in the I1 treatment (214.1 mm) considering the two year average values. Therefore, the I1 treatment provided the maximum growth and marketable yield (2.17 kg m-2). Water use efficiency was also the highest in the I1 treatment (10.2 kg m-3) because the lettuce yield decreased significantly with the decreasing irrigation quantity. However, total phenolic content and antioxidant activity in lettuce leaves were the highest in the I3 treatment. Moreover, I2 and I3 treatments provided higher mineral contents. While the potassium content in leaves was the most abundant among macro minerals (N, P, K, Ca, Mg, S, and Na), manganese content was the highest among micro minerals (Fe, Cu, Mn, Zn, and B). It could be said that lettuce can be irrigated with less irrigation quantities for obtaining higher mineral contents, total phenolic contents and antioxidant activity. This application can also provide water saving but cannot induce water productivity.
Andrew G. Reynolds and Christiane de Savigny

Cool Climate Oenology and Viticulture Institute, Brock University, St. Catharines, ON L2S 3A1

Key words: Fruit composition, soil texture, GPS, GIS, precision viticulture

Journal of Applied Horticulture, 2016, volume 18, issue 2, pages 100-122.

Abstract: The aim of this study was to test the hypothesis that soil texture would play a minor role in the determination of yield components, fruit composition, and wine sensory attributes of Chardonnay (i.e. the terroir effect), and that vine size, crop size and associated fruit environment would play the major roles. Five Chardonnay vineyards in the Niagara Peninsula of Ontario, Canada were chosen for study. These vineyards were located on sites with heterogeneous soil types to allow study of the impact upon yield, fruit composition and wine sensory attributes of: 1. Soil texture with mesoclimate kept constant; 2. The comparative magnitude of effects of soil texture and vine vigor. Vineyard blocks were delineated using global positioning systems (GPS), and a series of 72 to 162 data vines per site were geo-located within a sampling grid imposed on each vineyard block. Data were collected on soil texture, soil composition, tissue elemental composition, vine performance (yield components and weight of cane prunings), and fruit composition. These variables were mapped using geographical information systems (GIS) software and relationships between them were elucidated. Soil texture and composition were occasionally correlated to yield components and fruit composition but often these relationships were site-specific. Spatial relationships were common between % sand and clay, vine size, yield, berry weight, soluble solids (Brix), and titratable acidity (TA); however, relationships were both vineyard and vintage dependent. Several spatial relationships were apparent as well between vine size, yield, Brix, TA, and various soil/petiole composition variables, including organic matter, soil pH, cation exchange capacity, and soil/petiole N, P, K, Ca, Mg, and B. Spatial relationships between yield, berry weight, berry composition, vine size, and several soil physical variables suggest a likely soil basis to the so-called 'terroir effect'. Vine size, yield, and berry weight were stable temporally within individual vineyards despite differences in annual climatic conditions. Soil texture (% sand) was frequently associated with high vine size, yield, and berry weight. Vine size directly correlated with berry weight. TA was often correlated with vine size. Soil composition had little relationship to petiole composition, fruit composition or yield except in a few specific cases, e.g., between pH and soil K.
Yanbin Hua, Baotong Yang, Xin-Gen Zhou, Jun Zhao and Liulin Li

College of Horticulture, Shanxi Agricultural University, Taigu 030801, Shanxi, P. R. China. College of Engineering, Shanxi Agricultural University, Taigu 030801, Shanxi, P. R. China. AgriLife Research and Extension Center, Texas A&M University System, Bea

Key words: Fruit bagging, overrunning clutch, self-locking, paper bag with rubber bands and plastic rings

Journal of Applied Horticulture, 2016, volume 18, issue 2, pages 123-127.

Abstract: Bagging fruit on the trees in the orchard is a challenge to the fruit industry in China and many other countries due to the heavy labor requirement and low efficiency of the current fruit bagging methods. In this study, we developed a novel semi-automatic apparatus for bagging fruits to overcome these disadvantages. This apparatus adopts a mechanism similar to 'overrunning clutch' using the self-locking principle between nut and bolt to achieve the paper bags being progressively delivered by a screwed pipe and slid out individually. Such apparatus is of simplicity in design and efficiency in operation with a low cost. It does not require a battery or any of other sources of power to complete the process. This article describes the design and operation procedure of this apparatus in details. To our knowledge, this is the first apparatus to complete the fruit bagging process using the paper bags with rubber bands and plastic rings based on the new mechanism of operation.
N. Bumgarner and J. Buck

University of Tennessee, Knoxville, TN, USA, 37996. Formerly of Hort Americas, LLC, Euless, TX, USA.

Key words: Hydroponic, protected culture, light emitting diode, metal halide, lettuce, Lactuca sativa, greenhouse, high intensity discharge lighting

Journal of Applied Horticulture, 2016, volume 18, issue 2, pages 128-134.

Abstract: Lettuce (Lactuca sativa) is one of the most common vegetable crops produced in greenhouses in the United States. Yet, it is difficult to maintain consistent production cycles in many areas due to seasonal variation in ambient light. This presents a challenge to profitability, so, many growers utilize supplemental lighting to provide more consistent production in greenhouse leafy crop operations. Research has frequently been carried out to investigate the relationships between light, temperature, and carbon dioxide (CO2) in greenhouse lettuce crops to optimize production and profitability. Much of this work has been carried out using high intensity discharge lights (HID), specifically high pressure sodium (HPS) and metal halide (MH). Currently, growers are considering whether light emitting diode (LED) technology can augment or replace HID lighting for greenhouse-grown vegetables. To improve knowledge in this area, this study evaluated LED and MH lighting in Bibb lettuce crop in the Midwestern United States during low light seasons in 2014. Three lighting treatments were compared: 1) a naturally lighted control, 2) supplemental MH lighting, and 3) supplemental LED lighting. Three sequential runs comparing the three lighting treatments were carried out between January and April of 2014. At the conclusion of each run, fresh shoot weight for all plants was measured along with a chlorophyll content index and a subjective tipburn rating. Supplemental lighting increased biomass over naturally-lighted controls by 194%, 104%, and 39% in MH and 253%, 165%, and 55% in LED in runs one, two, and three, respectively across the two cultivars. Differences in the chlorophyll content index and tipburn rating were also observed in lettuce under both supplemental lighting treatments when compared to the naturally lighted control. This study illustrates that supplemental lighting can improve greenhouse lettuce yield during low light seasons, but suggests growers implementing supplemental lighting should carefully monitor and manage crop quality.
R. Khajehyar, E. Fallahi and M. Rahemi

Department of Horticultural Sciences, Faculty of Agriculture, Shiraz University, Shiraz, Iran. Department of Plant, Soil and Entomological Sciences, Parma Research and Extension Center, University of Idaho, 29603 University of Idaho Lane, Parma, ID 83660, USA.

Key words: Jasmonic acid, polyamines, chilling injury, citrus, cold storage.

Journal of Applied Horticulture, 2016, volume 18, issue 2, pages 135-137.

Abstract: Chilling injury is one of the most important problems of tropical and subtropical fruits during storage that can occur if the temperature falls below 5 oC. Polyamines and methyl jasmonate (MJ) are believed to prevent and inhibit chilling injury (CI) during storage. In order to find a suitable treatment to reduce CI of oranges (Citrus sinensis) during cold storage, a research was conducted with two concentrations of MJ and two concentrations of spermidine (Spd) and putrescine (Put) (1 and 1.5 mgL-1), applied as pre-storage treatments and fruits were stored at 2 oC for 1.5 months. Application of MJ and PAs reduced percentages of CI, decay, pitting, physiological decay (PHD), ion leakage, potassium leakage, and weight loss (WL) and firmness in the fruit as compared to control after the storage period. Put at 1 mgL-1 had significantly lower percentage ion leakage and pH although CI in this treatment was similar to other treatments. Fruit juice density was not affected by any of the treatments.

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