bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Resistant and Susceptible East European Pears on Development and Mortality of the Pear Psylla, Cacopsylla pyricola (Förster)
Authors: Bell Richard L.
Published: February 2019

Pear psyllids (Cacopsylla spp., Hemiptera: Psyllidae) are major pests of European pear (Pyrus communis L.) in North America and Europe. In breeding resistant cultivars, a thorough understanding of the nature of host resistance and susceptibility is essential for designing efficient and accurate methods to identify resistant host genotypes. A developmental assay was performed on six genotypes previously identified as highly resistant, moderately resistant, or susceptible to nymphal feeding. Plants were infested with first instars of Cacopsylla pyricola (Förster), and feeding, mortality, and larval stage were observed for 34 days. Host genotypes significantly differed in feeding antixenosis at day 1 after infestation. Differences in antibiosis were also evident, as mortality of nymphs was greater on the feeding-resistant genotypes. There were also differences in the total numbers of surviving psylla and those developing to adults. Survival was directly related to the feeding antixenosis. There were no significant differences among the feeding-susceptible and moderately resistant genotypes in population age structure, except at day 19, reflecting the advanced stage of the few nymphs that did survive. Early feeding antixenosis was associated with mortality, either through a lack of feeding stimulation, feeding inhibition, or because of a direct toxic effect of the resistant plant genotypes. The short-term feeding antixenosis assay is predictive of long-term mortality and, to a lesser extent, with delayed development. ‘Bartlett’ and the wild seedling Y-167 were confirmed as susceptible, ‘Karamanlika’ and NY10352 were confirmed as moderately resistant, and Bacui-1 and Bacui-2 were confirmed as highly resistant.
Energy-saving Seedling Production System for Super-forcing Cultivation of June-bearing Commercial Strawberry
Authors: Nakajima Ryoichi , Otagaki Shungo , Shiratake Katsuhiro , Matsumoto Shogo
Published: February 2019

Previously, we showed that a reduction of FaTFL2 (homolog of Arabidopsis thaliana TFL1) expression is a key signal for flowering in domesticated octaploid strawberries (Fragaria ×ananassa). Since FaTFL2 expression seemed to be regulated by temperature rather than by photoperiod, we investigated whether down regulation of FaTFL2 and floral meristem generation occurred at different temperature conditions. In addition to the conditions for a normal super-forcing cultivation system of an 8-hour photoperiod and day/night temperatures of 31.2 or 30/15 °C, flowering also was generated under the same photoperiod and day/night temperatures of day/night-half/night-half temperatures of 30/15/25 °C conditions. We demonstrate that the new super-forcing cultivation system is energy saving based on the reduction of FaTFL2 expression.
Growth, Quality Index, and Mineral Composition of Five Ornamental Cabbage Cultivars Grown Under Different Nitrogen Fertilization Rates
Authors: Cardarelli Mariateresa , Rouphael Youssef , Muntean Delia , Colla Giuseppe
Published: February 2019

The fertilizer nitrogen (N) inputs to some potted plants such as ornamental cabbage (Brassica oleracea L. var. acephala D.C.) are frequently higher than the actual demand. Optimization of N fertilization rate and selecting N-efficient cultivars are important approaches to increase the nitrogen use efficiency (NUE) and to reduce environmental pollution from nitrate leaching. The aim of this study was to assess the effect of increasing levels of nitrate (0.5, 2.5, 5, 10, or 20 mm of NO3−) in the nutrient solution on plant growth, quality, soil plant analysis development (SPAD) index, chlorophyll fluorescence, leaf pigments, mineral composition, and NUE in five ornamental cabbage cultivars (Coral Prince, Coral Queen, Glamour Red, Northern Lights Red, and White Peacock), grown in closed subirrigation system. ‘Glamour Red’ and ‘Northern Lights Red’ needed 3.3 and 2.9 mm of NO3− in the supplied nutrient solution, respectively, to produce 50% of predicted maximum shoot dry weight (SDW), whereas the vigorous cultivars Coral Prince, Coral Queen, and White Peacock needed 5.5, 4.7, and 4.3 mm of NO3−, respectively. Total leaf area (LA), SDW, SPAD index, N, Ca, and Mg concentrations increased linearly and quadratically in response to an increase of the nitrate concentration in the nutrient solution. Irrespective of cultivars, fertilizing above 10 mm NO3− produced high-quality plants (quality index of 5) and resulted in sufficiently high tissue concentrations of N, P, K, Ca, Mg, and Fe.
Simulated Seawater Flooding Reduces the Growth of Ten Vegetables
Authors: Sun Youping , Masabni Joseph , Niu Genhua
Published: February 2019

Excessive salinity in soil and irrigation water in combination with waterlogging in coastal regions can significantly reduce the productivity of many agricultural crops. To evaluate the plant growth responses to simulated seawater (SSW) flooding, seedlings of 10 vegetables (broccoli, chinese cabbage, chinese greens, cucumber, eggplant, kale, radish, ‘Red Crunchy’ radish, spinach, and tomato) were flooded with SSW at electrical conductivity (EC) of 44.0 ± 1.3 dS·m−1 or tap water at EC of 0.8 ± 0.1 dS·m−1 for 24 hours and grown subsequently for 2 weeks in a greenhouse. Chinese greens and cucumber plants died shortly after flooding with SSW, whereas other vegetables exhibited various degrees of visible salt damage. Chinese cabbage suffered the strongest reduction, whereas spinach, tomato, and eggplant exhibited the least decrease in dry weight (DW) due to SSW flooding in comparison with their perspective control. Two weeks after flooding treatment with SSW, net photosynthetic rate of broccoli, kale, spinach, and tomato was reduced by 43% to 67%, transpiration rate by 35% to 66%, and stomatal conductance (gS) by 51% to 82%. In summary, spinach, eggplant, and tomato were the most tolerant, whereas chinese cabbage, chinese greens, and cucumber were the least tolerant to SSW flooding.
Vegetation-free Width and Irrigation Impact Peach Tree Growth, Fruit Yield, Fruit Size, and Incidence of Hemipteran Insect Damage
Authors: Fisk Connie L. , Parker Michael L. , Mitchem Wayne
Published: February 2019

Orchard floor vegetation competes with peach trees for water and nutrients and may harbor pathogens and insects. Tree growth, fruit yield, and fruit size can be optimized through management of vegetation in the tree row and irrigation. Under-tree vegetation-free strip widths (0, 0.6, 1.2, 2.4, 3.0, and 3.6 m) and irrigation were studied in years four through eight of a young peach orchard to determine their effects on peach tree growth and fruit yield, harvest maturity, and fruit size. Immature fruit samples were collected during thinning in years four through six to determine the effect of the treatments on the incidence of hemipteran (catfacing) insect damage. Trunk cross-sectional area (TCSA), as a measure of tree growth, increased with increasing vegetation-free strip width; trees grown in the 3.6-m vegetation-free strip had TCSAs 2.2 times greater, on average, than trees grown in the 0-m vegetation-free strip. TCSA also increased with irrigation; trees grown with irrigation had TCSAs 1.2 times greater, on average, than trees grown without irrigation. Yield increased with increasing vegetation-free strip width, from 9.6 kg per tree in the 0-m plot to 26.5 kg per tree in the 3.6-m plot in year four, to 24.3 kg per tree in the 0-m plot and 39.6 kg per tree in the 3.6-m plot in year eight, for a total yield over years 4–8 per tree of 100 kg in the 0-m plot compared with 210 kg per tree in the 3.6-m plot. Yield, average fruit weight, and average fruit diameter increased with irrigation in three of 5 years; the other 2 years had higher than average rainfall reducing the need for supplemental irrigation. In 3 out of 5 years fruit in irrigated plots matured earlier than fruit in nonirrigated plots. In all years, fruit grown in the 0-m strip matured earliest and had the smallest diameter. Establishing a vegetation-free strip of as narrow as 0.6 m reduced the incidence of catfacing damage compared with the 0-m treatment, even though the orchard was on a commercial pesticide spray schedule. The least damage was seen with the industry standard vegetation-free strip widths greater than 3.0 m with or without irrigation.
Development of Bacterial Spot, Incited by Xanthomonas cucurbitae, in Pumpkin Fields
Authors: Ravanlou Abbasali , Babadoost Mohammad
Published: February 2019

This study was conducted to assess occurrence of bacterial spot, incited by Xanthomonas cucurbitae, on pumpkin leaves and fruit. Development of the disease was monitored in 9, 14, and 15 commercial pumpkin fields in 2009, 2010, and 2011, respectively, in Illinois. Bacterial spot was observed from 4-leaf growth stage until the green leaf tissue was unavailable. Three types of lesions were observed on leaves, which were described as Type I, Type II, and Type III lesions. Type I lesions were small (1 mm), angular, brown necrotic spots, and numerous on each leaf. Type II lesions were angular, beige in the center with brown halo, numerous on each leaf, and measured 1 to 4 mm. Type III lesions were angular, translucent spots with a narrow chlorotic halo, only a few spots on each leaf, and measured 4 to 8 mm. Incidence and severity of bacterial spot on leaves were the greatest when fruit began to turn to orange. Bacterial lesions were observed on fruit from 1 week after fruit set until harvest. Lesions on fruit were circular, water-soaked, sunken, with beige centers and chlorotic halo, and measured 1 to 3 mm. Occurrence of bacterial spot on fruit was assessed in 17, 50, and 65 commercial pumpkin fields in 2009, 2010, and 2011, respectively. The disease on fruit was observed in 100%, 80%, and 88% of the fields surveyed in 2009, 2010, and 2011, respectively. The incidence of fruit with bacterial spot in all fields surveyed was 46%, 35%, and 24% in 2009, 2010, and 2011, respectively.
Consumer Preferences for Traditional, Neonicotinoid-free, Bee-friendly, or Biological Control Pest Management Practices on Floriculture Crops
Authors: Wollaeger Heidi M. , Getter Kristin L. , Behe Bridget K.
Published: February 2019

Neonicotinoids have recently been implicated by the media as a contributing factor to the decline of honey and bumblebees. We sought to better understand consumer perceptions and willingness to pay for traditional, neonicotinoid-free, bee-friendly, or biological control pest management practices as growers may seek alternative management practices to systemetic insecticides. We conducted a nationwide Internet survey (n = 3082), where consumers answered attitudinal, comprehension, likelihood-to-buy, and demographical questions about indoor (marketed in 10-cm pots) and outdoor (marketed in 30-cm hanging baskets or 10-cm pots) floriculture products. The likelihood-to-buy questions were analyzed using conjoint analysis to determine which attributes had the greatest part-worth scores or which ones were viewed most positively by survey respondents. Of the total participants, 65.1% (n = 2002) of the subjects had purchased an annual flowering plant in the 12 months before the survey. Respondents reported that the most important plant health and appearance factors that affect their purchasing decisions were that the flowering plants have no plant damage, while the second most important factor was that plants have no insects on them. The least important factor in the ranking of stated importance was that no neonicotinoid insecticides were used during the production of the plant. This finding may have resulted from 56.6% of all participants who reported that they did not understand the term. For those who viewed the indoor 10-cm flowering plants (n = 1052), the plant species accounted for 41.2% of the decision to purchase the plant, followed by production type (32.8%) and price (26.0%). All three product attributes were of equal importance to the subjects who viewed the outdoor 10-cm flowering plants (n = 1024), whereas only price had a lower relative importance when compared with production type and species for those who viewed the 30-cm hanging baskets (n = 1006). Across all three studies, use of the term “bee-friendly” had the greatest economic value because it had the highest part-worth utility score, or the greatest willingness-to-buy. For the subjects who viewed the outdoor plants, “bee-friendly” and “use of beneficial insects” had greater economic value (with positive part-worth utility scores), but “neonicotinoid-free” and “traditional insect control” both had negative part-worth utility scores, indicating they were valued less and detracted from the dollar value of the plant. The term “bee-friendly” was worth up to five times more to those respondents that had bought a plant in the last 12 months compared with those who had not. Therefore, if ornamental plants are labeled with pest management practices, most consumers value the term “bee-friendly” more and will likely discount products labeled “neonicotinoid-free.”
Immature Embryo Germination and Its Micropropagation of Ilex crenata Thunb.
Authors: Yang Yujie , Zhang Donglin , Li Zhihui , Jin Xiaoling , Dong Jinying
Published: February 2019

To shorten Ilex seed germination time and speed up breeding cycles, immature embryos of Ilex crenata ‘Sky Pencil’ seedlings were removed from fruits at their heart-shape stage and cultured in vitro on Murashige and Skoog (MS) medium or Woody Plant Medium (WPM) with 3% sucrose and 0.65% agar. Cultures were incubated at 27 °C for 2 weeks in darkness and subsequently moved to a growth chamber with 14-hour photoperiod (115 μmol⋅m−2⋅s–1). Embryos began to germinate 2–3 weeks after culture. The highest germination rate was 91.67% under 1/4 MS medium. Embryos cultured on MS medium also had high germination rates and produced the longest seedlings to 8.02 mm. Nodal segments with one axillary bud taken from embryo germination seedlings were cultured on MS medium with various concentrations of cytokinins and auxins for micropropagation. Zeatin (ZT; 4-hydroxy-3-methyl-trans-2-butenylaminopurine) increased the number of shoots and shoot lengths significantly more than 6-benzylaminopurine (6-BA). The recommended ZT concentration should be 2.28 µM. Rooting induction could be established on 1/4 MS medium with various concentrations of indole-3-butyric acid (IBA) or 1-naphthaleneacetic acid (NAA). IBA at 4.14 µM produced the best rooting percentage (91.67%) and good-root quality. All rooted plantlets were transplanted into a mixture of peatmoss and perlite (1:1 v/v) and acclimatized in a mist system. The average survival rate was 88.8%. The rapid embryo germination protocol for Ilex crenata could save Ilex breeders at least 2 years compared with traditional seed germination.
Micropropagation of an Endangered Medicinal and Indigenous Multipurpose Tree Species: Erythrina abyssinica
Authors: Kirika Margaret W. , Kahia Jane W. , Diby Lucien N. , Njagi Eliud M. , Dadjo Colombe , Kouame Christophe
Published: February 2019

Erythrina abyssinica (E. abyssinica) is a multipurpose tree and a well-known medicinal plant which is conventionally propagated mainly by seeds. This method may produce a high degree of genetic variability and consequently decrease the medicinal value of the plant. Besides, the seeds have low germination rate and propagation is restricted to rainy season. Hence, there is need to develop a propagation protocol which produces a uniform plants and one which is not restricted to seasons. The objective of this study was to establish an in vitro propagation protocol for the multiplication of E. abyssinica. Seeds were sterilized and germinated in vitro to get sterile starting explants. Sterilization of the seeds was evaluated using different concentrations of a commercial bleach (JIK) ranging from 10%, 20% to 30% for 25 minutes. Kinetin (2.25, 4.50, 6.75, and 9.0 mg/L), and benzylaminopurine (BAP; 2.15, 4.30, 6.46, and 8.61 mg/L) were evaluated in separate experiments for their effect to induce microshoots from nodal explants. Rooting of the microshoot was carried out using half strength Murashige and Skoog (MS) media supplemented with indolebutyric acid (IBA) (0.20, 0.51, and 1.02 mg/L). Statistical analysis software (SAS) package was used to perform analysis of variance on the data to test the significance of the difference between treatments. The result of the sterilization experiment indicated that 10% JIK gave the highest percentage (55%) of clean seeds. Benzylaminopurine evaluated at 8.61 mg/L gave the highest mean number of microshoots (6.80 ± 1.24) after 28 days. On the other hand, IBA evaluated at 0.51mg/L gave the highest mean root length (6.00 ± 01.85 cm). The regenerated plants were acclimatized in the greenhouse and 65% survival rate was recorded after one month. With the increasing worldwide demand for medicinal plants as an alternative to prescription drugs, ex situ, in situ conservation programs and true to type mass propagation of E. abyssinica could benefit from the findings of this study. This is the first report on micropropagation of E. abyssinica.
Inhibitory Effects of Tropical Medicinal Plant Extracts on Urea Hydrolysis and Nitrification in Soil: A Preliminary Study
Authors: Zhao Muqiu , Zhao Huaibao , Du Qianjin , Shi Yunfeng
Published: February 2019

Hydrolysis and nitrification are the key steps of biological transformation of urea in soils, which control the loss of nitrogen (N) in terrestrial ecosystem. The inhibitory effects of plant materials on N transformation provide potential benefits for agricultural production and environmental protection. In this study, water-soluble and ethanol-soluble compounds were extracted from 24 tropical medicinal plant species in Hainan Island, southern China, with the aim of measuring their effects on urease activity (UA), nitrification potential (NP), and ammonium oxidizer number in a paddy soil, by a series of short (5 hours) and long-term (14 days) incubation experiments. Total solid yields and phenols contents of 48 medicinal plant extracts were also analyzed in this study. There were big differences in total solid yield and phenols content among the extracts of the selected tropical medicinal plant extracts. The phenols content of the plant extracts varied from 15.1 to 273.4 mg GAE/g extract (milligrams of gallic acid equivalents per gram of extract). A significant relationship between UA and NP of the soil treated with plant extracts and their phenols content was found, indicating that phenolic compounds are the major contributors to the inhibitory properties of these plants. Further studies indicated that the water extracts of Epimeredi indica aerial and Melia azedarach leaf, containing a high content of phenols, exhibited notable urease and nitrification inhibitory effects and reduced the number of soil ammonia–oxidizing bacteria, being promising sources of natural inhibitors for soil N transformation.
Effect of N Management on Root Yield and N Uptake of Radishes in Southern China
Authors: Yuan Wei-Ling , Yuan Shang-yong , Deng Xiao-hui , Gan Cai-xia , Cui Lei , Wang Qing-fang
Published: February 2019

Efficient nitrogen (N) fertilizer management is crucial for ensuring the maximum economic yield and reducing the risk of environmental pollution. The objective of this study was to determine the effect of N fertilizer management on root yield and N uptake of radish in southern China by using 15N isotope tracing. A 2-year field experiment was conducted with three N rates (0, 60, and 120 kg N/ha) and two different application proportions, viz, A [50% at basal, 20% at 15 days after seeding (DAS), 30% at 30 DAS] and B (30% at basal, 20% at 15 DAS, 50% at 30 DAS) for each N rate, which were expressed as N0, N60A, N60B, N120A, and N120B, respectively. The results showed that root yields were significantly increased with N rates increasing from 0 to 120 kg N/ha. The root yields for N120A and N120B were 67.60 t·ha−1 and 72.50 t·ha−1 at harvest, 64.07% and 66.67% higher than those for the treatments of N60A and N60B, respectively. Mean radish recovery of N fertilizer ranged from 25.90% at N120A to 32.60% at N60B, and N fertilizer residual rate in the soil ranged from 11.50% at N120A to 14.90% at N60B. About 17.50% to 35.70% of total uptake of 15N derived from basal fertilizer was absorbed at seeding stage. However, 61.87% to 80.18% of total uptake of 15N derived from topdressing fertilizer absorbed at root expanding stage. Therefore, appropriate nitrogen application with increasing topdressing nitrogen amount could increase root yield of radish and the nitrogen recovery efficiency. Nitrogen fertilizer application recommended was 120 kg N/ha with 30% for basal, 20% for 15 DAS and 50% for 30 DAS in this study.
Growth and Physiological Response to Nitrogen Deficiency and Re-supply in Leaf-vegetable Sweetpotato (Ipomoea batatas Lam)
Authors: Wei Meng , Zhang Aijun , Li Hongmin , Tang Zhonghou , Chen Xiaoguang
Published: February 2019

Nitrogen (N) is an essential macronutrient limiting plant growth and quality of leaf-vegetable sweetpotato (Ipomoea batatas Lam). The objective of this study was to investigate the effects of N deficiency and re-supply on growth, physiology, and amino acids in sweetpotato. Two leaf-vegetable sweetpotato cultivars, Pushu 53 and Tainong 71, were subjected to three treatments in hydro-culture: 1) N sufficiency, 2) N deficiency, and 3) N deficiency and subsequently with N re-supply. Compared with N sufficiency, N deficiency caused a decrease in vine growth, carotenoid and chlorophyll content (Chlt), root viability, photosynthesis, and nitrate reductase (NR) activity in both cultivars, but to a great extent in Tainong 71. Whereas N deficiency increased root growth and glutamine synthetase (GS) activity in both cultivars, and the increase in ‘Tainong 71’ was more obvious. Re-supply of N recovered the vine growth, root viability, Chlt, photosynthesis, NR, and GS activity, to a greater extent for ‘Pushu 53’ than for ‘Tainong 71’. N deficiency significantly decreased essential amino acids, including lysine, phenylalanince, isoleucine, tryptophane, leucine, and valine contents and nonessential amino acids, consisting of glutamic acid, aspartic acid, glycine, argnine, and proline content in both cultivars. These results indicated that the light leaf color leafy sweetpotato ‘Tainong 71’ is sensitive to the N availability and the dark green leaf color ‘Pushu 53’ is more tolerant to low N, which appear to reflect the differential response of two cultivars to their different adaptability to N availability.
Phytoremediation of Indoor Air
Authors: Thomas Creighton K. , Kim Kwang Jin , Kays Stanley J.
Published: February 2019

Volatile organic compounds (VOCs) in homes and offices represent a potentially serious health problem for exposed individuals. While certain indoor plants have been shown to remove VOCs in small test chambers, the results have not consistently translated to larger, more complex structures. We report the results of a mathematical model that assesses the effect of plants on the removal of benzene or other VOCs in buildings, incorporating the primary variables modulating indoor air VOC concentration. Building air volume, amount of plant material, VOC concentration and air exchange, VOC emanation, and plant phytoremediation rates can be altered over ranges reported in the literature, clarifying the relationship among these parameters and thereby identifying the most appropriate interior air remediation options. The results indicate existing published phytoremediation rates determined using small test chambers are far higher than can be achieved with static potted plants in buildings, and facilitated air movement through the plant media will most likely be essential for phytoremediation to be a viable means of improving indoor air quality.
Nikolai Ivanovich Vavilov: Plant Geographer, Geneticist, Martyr of Science
Authors: Janick Jules
Published: February 2019

Nikolai Ivanovich Vavilov (1887–1943), one of the pioneers of 20th century plant breeding, is best known for seminal work in identifying centers of origins and diversity for cultivated plants. Vavilov studied genetics with William Bateson from 1913 to 1914 at the John Innis Horticultural Institute. In 1921, he was chosen by Vladimir Lenin to head the Branch of Applied Botany in Petrograd (St. Petersburg) and rose to be the Director of the All-Union Institute of Agriculture in Leningrad, where he oversaw agricultural research for the entire country. By 1934, Vavilov established more than 400 research institutes and experiment stations with a staff of 20,000. His efforts established the Soviet Union as a world leader in genetics and plant breeding in the 1920s and early 1930s. Vavilov carried out an extensive series of expeditions worldwide, including the United States, to collect germplasm; and he created the world’s largest repository, over 250,000 seed accessions. However, as a result of famine in the Soviet Union in the late 1920s, partly as a result of forced collectivization of peasants, Vavilov came in conflict with an ambitious agronomist, Trofim Lysenko, who came to prominence with an agricultural technique proposed in 1928, of exposing chilled, soaked seeds of wheat (dubbed vernalization) to extend production in northern areas of Russia. Lysenko’s rejection of Mendelian genetics won the support of Joseph Stalin, leading to the arrest and death sentence of Vavilov, although this was later commuted to 20 years imprisonment. Vavilov died of starvation in prison in 1943, thus entering the select group of martyrs of science along with Gordiano Bruno, Galileo Galilei, Antoine Lavoisier, and Georgii Karpechenko.
Molecular-genetic Extensions of Vavilov’s Predictions
Authors: Folta Kevin M.
Published: February 2019

Vavilov’s Law of Homologous Series indicates that heritable variation for a given trait will occur in different species based on parallel selection. The conclusion comes from Vavilov’s study of extensive collections and careful attention to phenotypic variation across taxa. The same examination of variation can be applied to traits using the power of genetic and genomic resolution, because parallel traits would be expected to be governed by the same genetic loci, and perhaps even common mutations. In this review, these concepts are applied to two central traits—the control of “shattering” of kernels in cereals and in the control of photoperiodic flowering. One of the strengths of the law is that it can make predictions about traits and perhaps the genes or genomic regions that control them. With respect to genetic variation, the occurrence and physical location of genes associated with kernel retention may be predicted. Many grains share mutations, such as the Sh 1 gene, which were selected in parallel. Selection of the Sh1 gene led to higher yields due to better kernel retention. While the genes affected are often the same, the types of mutations are not, implying convergent selection. Flowering time is governed by multiple loci, so variation may be attributed only to a few candidates, yet because of the number of regulators the predictive power of the law is lower. The modern application of the Law of Homologous Series is that it allows basic researchers or plant breeders to make predictions about the genes controlling key traits, although the genetic basis of variation is likely not conserved.
Ripening Associated Red Color Development Masks Sunburn Browning in Apple Peel
Authors: Makeredza Brian , Marais Helen , Schmeisser Michael , Lötze Elmi , Steyn Willem J.
Published: February 2019

Red color development toward harvest may conceal superficial blemishes such as sunburn browning in apple peel. Masking of sunburn may result in the underestimation of sunburn incidence in full red and blushed cultivars and may result in inaccurate assessments of sunburn susceptibility of various cultivars. However, anthocyanin accumulation may potentially also increase sunburn by decreasing the albedo and thereby increasing the fruit surface temperature (FST). Conversely, it has been proposed that anthocyanins may protect peel against photothermal stress. We assessed the effect of anthocyanin accumulation on the visible sunburn incidence in two trials. In the first trial, hue angle, blush coverage, sunburn incidence, and sunburn severity were assessed on fully exposed apples of the green cultivars, Granny Smith and Golden Delicious, as well as the blushed cultivars, Royal Gala, Fuji, Braeburn, and Cripps' Pink, and the full red cultivar Topred, a month before harvest and again at harvest. Increases in sunburn toward harvest were greater in green than in red and blushed cultivars. Accumulation of anthocyanins seemed to decrease the conspicuousness of sunburn browning, which is a superficial form of sunburn while sunburn necrosis, which manifests as sunken black spots, was not masked by anthocyanins. In the second trial, ‘Granny Smith’, ‘Fuji’, and ‘Cripps’ Pink’ apples with moderate sunburn browning, sunburn necrosis, or no sunburn were tagged 1 month before the expected harvest date. Sunburn browning was apparent and significantly increased in severity in ‘Granny Smith’ while the severity of visible sunburn browning symptoms decreased in ‘Fuji’. Sunburn severity increased at the same level in the control and sunburn browning ‘Cripps’ Pink’ fruit. Measurement of maximal photochemical efficiency of the originally undamaged apples and the sunburn browning treatment indicated comparable damage levels in the peel of the sunburn browning treatment in all three cultivars. No masking of sunburn necrosis occurred. Our data thus provide clear evidence that anthocyanin accumulation masks sunburn browning in blushed and red cultivars, but does not seem to increase the susceptibility or protect these cultivars from sunburn damage. The incidence of sunburn browning is likely to be underestimated in red and blushed cultivars, with compounding effects on comparative studies of sunburn susceptibility between cultivars and sunburn physiology.
Seed Germination Biology of Four Pomegranate (Punica granatum) Cultivars from Xinjiang, China
Authors: Shalimu Dilinuer , Li Ke , Baskin Carol C. , Baskin Jerry M. , Liu Yujun
Published: February 2019

Pomegranate is an important fruit crop cultivated in many countries, and development of new cultivars depends on the plant breeders being able to produce plants from seeds. Poor quality and low yield of cultivars are widespread problems that greatly restrict development of the pomegranate industry. Our purpose was to gain a better understanding of the seed dormancy-breaking and germination requirements of four cultivars of pomegranate from Xinjiang Province, China, which would be useful in improving old cultivars and developing new ones. Fresh pomegranate seeds incubated on moist filter paper imbibed water, but they germinated to only 16% to 20%. Sulfuric acid scarification, cold stratification, and warm followed by cold stratification significantly increased germination percentages. Seeds soaked in concentrated H2SO4 for 40 minutes followed by cold stratification for 2 months germinated to 65%, and those warm stratified for 1–3 months followed by cold stratification for 2 months germinated to 75% to 80%. Seeds of pomegranate have nondeep physiological dormancy (PD).
High Tunnel versus Climate-controlled Greenhouse: Transplant Time and Production Environment Impact Growth and Morphology of Cold-tolerant Bedding Plants
Authors: Gerovac Joshua R. , Lopez Roberto G. , Mattson Neil S.
Published: February 2019

Commercial bedding plant production in northern latitudes often begins in late winter and continues through spring, when average outdoor temperatures require growers to actively heat their greenhouses (GHs). High tunnels (HTs) offer energy savings as they are passively heated and cooled structures that have a low initial cost. As a result, they have been used in northern latitudes to advance and extend the growing season and improve the quality of high-value horticultural crops. However, there is limited published information on growing bedding plants in HTs in northern latitudes. Our objectives were to quantify the effects of transplant date in an HT with or without a rowcover (RC) compared with a traditional heated GH on the growth and morphology of three cold-tolerant bedding plant species at two northern latitude locations, Purdue University (Purdue) and Cornell University (Cornell). Seedlings of snapdragon (Antirrhinum majus L. ‘Liberty Classic Yellow’), dianthus (Dianthus chinensis L. ‘Telstar Crimson’), and petunia (Petunia ×hybrida Vilm.-Andr. ‘Wave Pink’) were transplanted on weeks 13, 14, and 15 in 2012 (Purdue) and 2013 (both locations) and moved to either a glass-glazed GH or an HT without (HT) or with a rowcover (HT+RC). Several quality measurements increased when plants were grown in the HT compared with those grown in the GH. Dianthus and petunia transplanted at Purdue during week 13 in the HT and HT+RC were 33% and 47% shorter and had 51% and 31% more visible buds, respectively, compared with those grown in the GH. Similarly, petunia transplanted at Cornell during week 13 in the HT and HT+RC were 45% and 43% shorter, respectively, than their GH counterparts. The shoot dry mass of dianthus and snapdragon at Purdue was significantly higher when grown in the HT compared with the GH, regardless of transplant week or the use of RC likely because of increased daily light integral (DLI) in the HT environment. There was about a 1-week delay from transplant to first open flower for week 13 dianthus (at Purdue) and petunia (at both locations) when finished in the HT or HT+RC vs. their GH counterparts. Such a delay would be acceptable to growers who want to reduce the use of chemical growth regulators and heating costs. However, at both locations snapdragon transplanted on week 13 to the HT or HT+RC environments were delayed by 22 to 26 days compared with the GH. A delay of over 3 weeks could interfere with a grower’s production schedule, possibly making this crop unsuitable for production in northern latitude HTs.
Suaeda glauca Can Be Produced Hydroponically at Moderate NaCl Salinity
Authors: Kong Yun , Zheng Youbin
Published: February 2019

Suaeda glauca is an annual halophyte growing in saline–alkali environment in North China. To evaluate the potential of producing S. glauca as a vegetable at moderate NaCl concentrations, plants were grown in nutrient solutions with 6, 8, and 10 mm NaCl, and with 200 mm NaCl as a control. Results showed that main stem length, true leaf number, side branch number, and canopy width of plants in 6–10 mm NaCl were not significantly different from those in 200 mm. Also, no significant differences in fresh and dry weights of individual plants, marketable yield, and water use efficiency of the plants were observed between 6–10 and 200 mm NaCl treatments. Despite remarkable decreases in sodium uptake, similar water consumptions by the plants were obtained in 6–10 vs. 200 mm NaCl. The results suggest that S. glauca is a potential candidate for hydroponic production as a vegetable at moderate NaCl salinity, since growth attributes and biomass accumulation were not reduced when grown at lower salinity levels, despite with decreased sodium uptake.
A Review of Weed Control Practices in Landscape Planting Beds: Part I–Nonchemical Weed Control Methods
Authors: Marble S. Christopher , Koeser Andrew K. , Hasing Gitta
Published: February 2019

Weed control continues to be one of the most expensive and time consuming aspects of landscape maintenance. Many homeowners are becoming more interested in nonchemical pest-management strategies due to increasing concern over the environmental impact of pesticide use. Nonchemical landscape weed control can be achieved using mechanical disruption (e.g., mowing, hand-pulling, hoeing, and tilling), physical barriers, or cultural control methods (e.g., mulching and plant selection). However, the best results are almost always achieved when employing a variety of methods (often involving chemical control methods). In adopting a weed control strategy, client expectations and weed tolerances must be addressed. While a virtually weed-free landscape is possible without the use of herbicides, this goal often requires a significant amount of time and money, and requires more planning to be successful. The goal of this manuscript is survey the literature pertaining to nonchemical weed control in landscape planting beds and determine: 1) the most effective strategies; 2) the advantages and disadvantages of common practices; and 3) highlight areas where research is needed or improvements could be made.
Effect of Biochar Amendments on Peach Replant Disease
Authors: Atucha Amaya , Litus Greg
Published: February 2019

The use of biochar as a soil amendment has generated interest all over the world, and it has been advocated as a means to improve soil fertility and sequester carbon. The objective of this study was to test if the use of pinewood biochar could reduce the detrimental effects of replant disease (RD) on peach tree growth and biomass production. An RD-susceptible peach rootstock, Lovell, was grown in soil from a peach replant site (control), sterilized soil (sterilized), and biochar-amended soil at 10% and 20% (v/v) [low biochar (LB) and high biochar (HB), respectively], all from the same site. Trunk diameter increase was measured weekly; total aboveground and belowground biomass was determined by harvesting a subsample of plants at 11, 22, and 33 weeks after planting. Soil samples, and foliar and root tissue samples were collected before each harvesting date and analyzed for nutrient content. Total aboveground and belowground biomass production was significantly higher in the biochar and sterilized soil treatment (S) compared with the control. Root carbon (C*) content was significantly greater in the HB treatment compared with the control. Soil nitrate-N was significantly greater in the HB treatment by the third harvesting date, and foliar magnesium (Mg) concentrations were significantly higher in both biochar treatments for all harvesting dates. The results from this study provide evidence that biochar may alleviate RD in peach trees.
Adventitious Bud Induction and Plant Regeneration from Stem Nodes of Salvia splendens ‘Cailinghong’
Authors: Yu Ling , Chen Hongwei , Hong Peipei , Wang Hongli , Liu Kefeng
Published: February 2019

Salvia splendens is a widely used ornamental bedding plant; however, the limited propagation method has decreased its quality and yield. Through years of selection, we have obtained a new variety of S. splendens with weak apical dominance and named it as ‘Cailinghong’. To establish an effective method for regeneration of S. splendens ‘Cailinghong’, different explants, including leaves, receptacles, petioles, stem nodes, and stem segments were used for adventitious bud induction. Next, various combinations of plant growth regulators (PGRs) were selected for bud and root induction, which were assessed by adventitious bud initiation rate and proliferation rate, as well as root induction rate. Meanwhile, the survival rate of transplanted plantlets was also calculated. As a result, stem nodes were found easy to be induced to form buds, and the optimum medium component was 1/2 Murashige and Skoog (MS) medium supplemented with 0.45 µM naphthalene acetic acid (NAA), 8.88 µM 6-benzylaminopurine (6-BA), and 2.46 µM 3-indolebutyric acid (IBA) for plantlets induction, whereas 1/4 MS medium supplemented with 2.23 µM NAA for root induction. Furthermore, the survival rate of transplanted plantlets was up to 80%, and all regenerated plantlets were normal in phenotype. Therefore, cultured in 1/2 MS medium with combined PGRs, whole plantlet of S. splendens ‘Cailinghong’ could be regenerated directly from stem node.
Premiums and Discounts for Plant Patents and Trademarks Used on Ornamental Plant Cultivars: A Hedonic Price Analysis
Authors: Drew Jennifer , Yue Chengyan , Anderson Neil O. , Pardey Philip G.
Published: February 2019

The value and role of intellectual property (IP) rights pertaining to plant innovations and their economic consequences on plant values is largely unknown. A hedonic pricing model was adapted to the characteristics of the U.S. wholesale ornamental plant market, specifically the bedding, garden plant and nursery plant markets, to analyze two forms of IP rights used on plants (i.e., plant patents and trademarks). By controlling plant-specific attributes and a variety of market variables that might affect plant values, our empirical analysis reveals sizable price premiums for plant patents that may have been masked in other studies. As expected, plant patent premiums vary considerably between species where the costs of producing and marketing new cultivars differ greatly. Surprisingly, we find that the use of trademarks have a negative effect on plant prices.
Effect of Application Ratio of Potassium over Nitrogen on Litchi Fruit Yield, Quality, and Storability
Authors: Yang Baomei , Li Guoliang , Yang Shaohai , He Zhaohuan , Zhou Changmin , Yao Lixian
Published: February 2019

Soils of litchi orchards in China are commonly deficient in nitrogen and potassium. The cultivar Feizixiao litchis planted in a typical acidic upland orchard, which is low in nitrogen and potassium, were used as a subject in field experiments with different ratios of potassium to nitrogen (K2O:N = 0.6, 0.8, 1.0, 1.2, and 1.4). Field experiments were conducted from 2009 to 2012. The effects of K2O:N ratio on the yield, quality, and storability of litchi were investigated and discussed. Results indicated that with the increase of K2O:N ratio, fruit yield initially increased and then decreased, and litchi had the highest yield when K2O:N was 1.2. When K and N fertilizers were applied at the ratio of 1.2, litchi had a better fruit quality with higher vitamin C content, soluble sugar, and soluble solid. With the increase of K2O:N ratio, healthy fruit rate initially increased and then decreased. This rate reached the maximum value when K2O:N was 1.2. Meanwhile, fruit-rotting rate, peel-browning index, cell membrane permeability, and peroxidase (POD) activity decreased at first and then increased and reached the minimum value when the K2O:N ratio was 1.2. Therefore, litchi fruit had the highest yield, better quality, and best storage property when K2O:N was 1.2. Thus, this ratio is recommended for the main litchi production areas in China.
The Contribution of Different Spectral Sections to Increase Fresh Weight of Boston Lettuce
Authors: Kong Shih-Wei , Chung Hsin-Ying , Chang Ming-Yi , Fang Wei
Published: February 2019

Six types of light sources [0G, 20G, 40G, cool-white light-emitting diode (LED CW), cool-white fluorescent lamp (FLCW), and plant light fluorescent lamp (TLRA)] were used as the sole light sources to cultivate boston lettuce (Lactuca sativa L. cv. Ostinata). The photosynthetically active radiation (PAR) range was separated into five sections and the contributions of each spectral section on fresh weight (FW) were quantified. The results indicate that the conventional method of separating PAR into red, green, and blue at 100 nm apart was not accurate enough to clarify the contribution of different spectral sections to FW of boston lettuce. Green light (525–575 nm) at less than 30% of PAR is even more important than red (625–700 nm) and blue (400–475 nm) to plant growth. Yellow light (575–625 nm) has very little effect on plant growth.
Production of Pepper Cultivar Palermo Grafted onto Serrano de Morelos 2, Jalapeño, and Three Commercial Rootstocks
Authors: Doñas-Uclés Francisco , Pérez-Madrid Diego , Amate-Llobregat Celia , Rodríguez-García Enrique M. , Camacho-Ferre Francisco
Published: February 2019

In the southeast of Spain, specifically in the province of Almería, pepper production represents 1.70% of the total pepper (Capsicum annuum L.) production in the world, which in turn represents 31.8% of the European production. In the last 10 years, production has remained stable between 7,240 and 10,997 ha. Due to the economic importance of this crop in the region, more improvements of the production techniques have been adopted. The reduced number of commercial rootstocks of peppers, which really improve yield in this crop, causes a continuous search for new genotypes. In this experiment, five pepper rootstocks were evaluated in an experimental design of randomized blocks with six treatments and three repetitions. The rootstocks used were: ‘Serrano de Morelos 2’ (SCM-334), ‘Jalapeño’, ‘Oscos’, ‘AR 9604040’, and ‘Tresor’. The cultivar grafted onto them was ‘Palermo’ also used as a control test. SCM-334 cultivar used as rootstock has a similar behavior in the production parameters measured as the commercial pepper rootstocks which were used. ‘Jalapeño’ and ‘SCM-334’ demonstrated different behavior in plant vigour compared with the others treatments. There is no interrelationship between production and plant vigour provided by the rootstock.
Who Decides to Give a Gift of Fresh Flowers? The Effects of Givers and Receivers on the Likelihood of Buying Fresh Flowers for Gifts
Authors: Huang Li-Chun , Lin Yen-Chun
Published: February 2019

As gifts are an important market sector for selling fresh flowers, this study investigated the effects of the characteristics associated with the dyads of givers and receivers on the probability of buying fresh flowers as gifts. Based on the theory of gift giving, several factors were hypothesized to influence the probability of buying fresh flowers as gifts, including givers’ financial capability and the perceived gift values of flowers, as well as knowledge of receiver’s needs, preferences, and difficulty to please. A self-administered questionnaire survey was conducted to test the hypotheses. Results of the statistical analysis based on 394 valid questionnaires revealed that the perceived gift values of flowers, i.e., the economic value, functional value, social value, and expressive value, were the most important factors for the consumer decision of whether to buy fresh flowers as gifts. However, different gift values were emphasized for fresh flowers across different relational ties. For example, economic value was the key value when the receivers were parents, whereas social value and expressive value were emphasized when the receivers were romantic partners. Different from many previous studies, this study revealed that financial capability did not influence the likelihood of givers deciding to purchase fresh flowers for gifts. The study results implied that when promoting fresh flowers for gift use, the gift values of fresh flowers need to be emphasized to consumers.