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Open access

Sabahudin Hadrović, Filip Jovanović, Sonja Braunović, Saša Eremija, Zoran Miletić, Snežana Stajić, and Igor Golić

To select woody fruit species for biomass cropping, a study of the carbon and nitrogen content of the bark and wood of five wild fruit species in Southwest Serbia was conducted. Compared with common hazel, wild cherry, walnut, and european pear, the european crab apple has a high potential for carbon and nitrogen storage, representing a promising fruit species for biomass production.

Open access

Ariana P. Torres, Alicia L. Rihn, Susan S. Barton, Bridget K. Behe, and Hayk Khachatryan

Online advertising is becoming a mainstay business practice to reach firms’ customer bases. Yet, the adoption and use of online advertising in the green industry are topics that have not been adequately researched. Using a national survey of green industry firms conducted in 2019, this research uses a double-hurdle model to investigate factors that impact firms’ adoption of, and amount spent on, online advertising. Our results show that one-third of the companies invested in online advertising. Of those investing in online advertising, the average percentage of online advertising as a share of all advertising expenditures was 46%. Small businesses were less likely to invest in online advertising compared with larger businesses; however, once they invested in online advertising, the percentage of investment was 25% higher among small firms when compared with their larger counterparts. Increasing years in operation as well as trade show participation was related to a 3% decrease in likelihood to use online advertising. Business owners who perceived hiring competent employees as a barrier to business growth invested 19% less of their advertising budget in online channels, which may indicate a lack of human resources to advertise online. We also compared the industry results with data from a 2014 survey and found the amount invested in online advertising increased ≈3% to 5% between studies. The percentage in wholesale sales influenced the amount spent on online advertising in 2014 but not in 2019. Being a small firm in 2014 increased the amount spent on online advertising, but the effect was 14% lower in 2019. In 2014, firms located in the Pacific, Southcentral, and Southeast U.S. regions invested more in online advertising compared with other regions, but in 2019, the only geographic difference was that firms in the Great Plains spent less on online advertising. Despite their lower adoption rates, the increased expenditures on online advertising implies that smaller firms that implement online advertising receive value through that channel and are willing to allocate more resources to leverage its reach. Firms contemplating adopting and investing in online advertising should consider their resource availability and marketing goals related to reaching different customer groups through online advertising.

Open access

Eliezer S. Louzada and Chandrika Ramadugu

Grapefruit [Citrus ×aurantium (synonym C. ×paradisi)] is an important citrus commodity that originated in Barbados in the 17th century. Grapefruit is the youngest member of the genus Citrus. Most commercially important grapefruit cultivars arose through natural and induced mutations, not traditional breeding, of the white-fleshed and seedy Duncan grapefruit. Now, cultivars with a range of flesh colors exist; the pigmentation is correlated with lycopene content. A bud sport mutant of grapefruit discovered in Texas has a deep golden-colored flesh, significantly different from the typical reddish pigmentation. In this review, we discuss grapefruit’s journey from its origin in Barbados and its global establishment including production, marketing, drug interactions, cultivar development, genetic diversity, and commercially significant cultivars.

Open access

Jessie M. Godfrey, Louise Ferguson, and Maciej A. Zwieniecki

Salinity’s many stresses may not kill a relatively salt-tolerant perennial in one season, but they can still deplete or modify nonstructural carbohydrate (NSC) pools. Any change to the quantity or quality of NSC reserves may have detrimental effects on phenology and reproduction, as well as yield, in tree crops. This study integrates salinity’s infringement on the energy margins of pistachio rootstock ‘UCB-1’ (an interspecific hybrid of Pistacia atlantica and P. integerrima) at senescence by measuring sugar and starch pools in wood, bark, and roots after treatment with ≈100 days of moderate to high salinity (50–100 mm NaCl and 10–20 mm CaCl2). Supported by a second experiment using sodium orthovanadate (NaOV) to block active xylem retrieval in the same hybrid pistachio rootstock, we conclude that retrieval of Na+ from xylem sap may allow for the preservation of NSC pools (particularly, starch) in mature xylem tissues by limiting the demand for carbon-based osmoticum (sugars). In contrast, younger growing tissues (bark and fine roots) were found to counteract salinity by degrading carbon-dense starch into osmotically active sugars at the expense of total NSC reserves, suggesting a physiological shift toward protection/isolation from environmentally pervasive but potentially toxic salts in these tissues.

Open access

Luiz C. Argenta, Sérgio T. de Freitas, James P. Mattheis, Marcelo J. Vieira, Claudio Ogoshi, Luiz Carlos Argenta, Sérgio T. de Freitas, James P. Mattheis, Marcelo J. Vieira, and Claudio Ogoshi

The objectives of this study were to characterize and quantify postharvest losses of apples under commercial conditions in Santa Catarina state, Brazil. Two experiments were conducted using ‘Gala’ and ‘Fuji’ apples. The first experiment was to characterize and quantify the most important causes of loss of fruit treated or not treated with 1-methylcyclopropene (1-MCP) then held in controlled atmosphere (CA) storage. This experiment was conducted in commercial storage facilities from 2007 to 2010. In each year, 10 samples of ≈380 kg each for ‘Gala’ and 400 kg each for ‘Fuji’ were collected from bins of commercially harvested fruit from each of 15 ‘Gala’ and 17 ‘Fuji’ orchards. Half of the samples from each orchard were treated with 1-MCP at harvest. Fruit were stored in CA, at 0.7 °C, for 150 to 300 days. After storage, one subsample of 100 disorder-free apples were selected from each sample and held at 22 °C for 7 days to simulate shelf-life conditions. The fruit were analyzed after CA storage and shelf life for the incidence of disorders. The second experiment was conducted in 2011 to identify the main fungi causing decay during storage. In this study, apples were stored in 10 commercial CA storage rooms at 0.7 °C for 180 to 240 days. After storage, fruit with decay symptoms were collected at the commercial sorting line. A total of 10 samples of 100 decayed apples were taken throughout the sorting period for each cultivar and storage room. The fungal decays were identified by visual symptoms on each fruit. Total apple losses during storage varied from 3.9% to 12.1% for ‘Gala’ and 6.6% to 8.4% for ‘Fuji’, depending on the year and 1-MCP treatment. During storage, deterioration caused by fungal decay was ≈60% and 80% of total losses for ‘Gala’ and ‘Fuji’, respectively. During shelf life, additional losses caused by fungal decay ranged from 8.4% to 17.6% for ‘Gala’ and 12.4% to 27.2% for ‘Fuji’, depending on the year. Senescent breakdown and superficial scald were the major physiological disorders. 1-MCP treatment had no effect on losses due to decay. Bull’s-eye rot, blue mold, gray mold, and alternaria rot were the most prevalent fungal decay symptoms, accounting for 52%, 27%, 9% and 10% of ‘Gala’ losses and 42%, 25%, 18% and 5% of ‘Fuji’ losses, respectively. Sources of variability for losses among years and orchards is discussed.

Open access

Marisa Y. Thompson, Jennifer J. Randall, Dawn VanLeeuwen, and Richard J. Heerema

Regarding pecan (Carya illinoinensis), alternate bearing, which is a biennial fluctuation of crop yield, is a major hindrance for the pecan industry. Little is known about the internal cues that trigger pecan shoots to become reproductive. This 2-year study approached the mysteries of alternate bearing of pecan by determining whether pecan homologs of three genes known to control floral initiation in other species are expressed differently at various times of the growing season or in distinct plant tissues, and whether expression of these genes can be manipulated by plant growth regulator (PGR) application when compared with an untreated control group. The flowering genes of interest were pecan homologs of leafy (CpLFY), apetala1 (CpAP1), and flowering locus t (CpFT). During year 1 (2014), PGRs ethephon and gibberellin GA3 were applied at the shoot level 1 week before each of three tissue sampling dates (13 June, 3 July, 29 July). During the following year (2015), two more PGRs were added to the study [a second double rate (2X) of gibberellin GA3 and ethylene inhibitor aminoethoxyvinylglycine (AVG)] for a total of four PGRs (applied on 10 June, 1 July, and 23 July) plus the untreated control. Experimental leaf and bud tissues were sampled from fruiting and nonfruiting shoots on mature ‘Western’ pecan trees and analyzed separately. Normalized expression levels of CpLFY and CpAP1 were significantly higher in buds than in leaves. Normalized expression of CpLFY in bud tissues differed statistically based on the sampling date in 2014, with the earliest date (13 June) having higher expression than the two later dates that year. In 2015, a treatment × date interaction revealed that, compared with the untreated control, CpLFY expression was significantly lower in shoots treated with both gibberellin GA3 dosages on 1 July. A few weeks later (23 July), CpLFY expression was lower in the 2X GA3 treatment group and higher in samples treated with AVG. In 2014, CpAP1 expression in buds was significant, with a treatment × date interaction in which ethephon increased CpAP1 expression, but only on one date (29 July). In 2015, bud CpAP1 expression was significantly higher in fruiting than in nonfruiting shoots; however, again, only on one date. The results reveal differential expression of these key flowering genes based on tissue type, sampling date, and fruiting status of the shoot and PGR treatment. Results suggest that more research of the effects of PGRs is necessary for understanding the flowering behavior of pecan and mitigating the intensity of alternate bearing.

Open access

Taifeng Zhang, Jiajun Liu, Sikandar Amanullah, Zhuo Ding, Haonan Cui, Feishi Luan, and Peng Gao

The plant compact and dwarf growth habit is an important agronomic trait when breeding watermelon (Citrullus lanatus) cultivars because of their reduced vine length, high-density planting, and better land utilization; however, the genetic basis of the dwarf growth habit is not well-known. In this study, the plant population of six generations, P1, P2, F1, F2, BC1P1, and BC1P2, were studied. A genetic segregation analysis demonstrated that dwarfism is mainly controlled by a single recessive Cldw gene. Furthermore, whole-genome sequencing of two distinct watermelon cultivars, W1-1 (P1) and 812 (P2), was performed and preliminarily mapped through a bulked segregant analysis of F2 individuals that revealed the Cldw gene locus on chromosome 9. Two candidate genes, Cla015407 and Cla015408, were discovered at the delimited region of 43.2 kb by fine mapping, and gene annotation exposed that the Cla015407 gene encodes gibberellic acid 3β-hydroxylase protein. In addition, a comparative analysis of gene sequence and cultivars sequences across the reference genome of watermelon revealed the splice site mutation in the intron region of the Cldw gene in dwarf-type cultivar 812. The quantitative real-time polymerase chain reaction exhibited a significantly higher expression of the Cla015407 gene in cultivar W1-1 compared with 812. There was no significant difference in the vine length of both cultivars after gibberellic acid treatment. In brief, our fine mapping demonstrated that Cla015407 is a candidate gene controlling dwarfism of watermelon plants.

Open access

Ed Stover, Chandrika Ramadugu, Mikeal Roose, Joseph Krystel, Richard F. Lee, and Manjunath Keremane

Asiatic citrus canker (ACC) foliar lesions were evaluated on progenies of 84 seed-source genotypes (“parent genotypes”) from the Citrus Variety Collection (CVC) of the University of California at Riverside (UCR) of Citrus trifoliata and hybrids between C. trifoliata and other Citrus species and hybrids. Trees were planted Aug. 2013 in a completely randomized design at the Fort Pierce U.S. Department of Agriculture (USDA) grove. Plants were assessed visually Aug. 2017, Sept. 2019, and Sept. 2020 for distinctive ACC lesion incidence and severity. Progeny were compared by parent genotypes using nonparametric analysis. Incidence of ACC [percentage of leaves displaying symptoms, verified by quantitative polymerase chain reaction (qPCR) to be associated with Xanthomonas citri pv. citri] across parent genotypes ranged from 8% to 80% (mean, 49%) of leaves affected in 2017, from 4% to 58% (mean, 29%) in 2019, and 8% to 46% (mean, 25%) in 2020. In 2017, of 49 C. trifoliata parent genotypes, only four separated from the two highest ACC-incidence statistical categories [Citrus Research Center (CRC) 3345, 3484, 3888, and 4017]. whereas 29 of the 35 C. trifoliata hybrids displayed lower ACC incidence, which separated from the two highest statistical categories. In 2019, of the C. trifoliata, only six separated from the highest ACC-incidence statistical category (CRC 3330, 3484, 3547, 3549, 3876, and 3888), whereas all 35 C. trifoliata hybrids displayed lower ACC incidence and separated from the highest statistical category, and 26 hybrids separated from 18 of the C. trifoliata. In 2020, only three C. trifoliata separated from the highest ACC-incidence statistical category (CRC 2861, 3549, and 3888) and 20 hybrids separated from 18 of the C. trifoliata. By parent genotype, ACC incidence correlated substantially between each pair of the 3 years, with r 2 values of 0.39, 0.57, and 0.65. Of 34 hybrids validated, similar numbers had C. trifoliata, grapefruit (C. ×aurantium var. racemosa), and sweet orange (C. ×aurantium var. sinensis) chloroplasts. Chloroplast type affected ACC incidence and severity, but not in a consistent manner. Near-isogenic groups within C. trifoliata, as determined by DNA markers, were associated with some statistically different ACC sensitivity. Overall, hybrids of C. trifoliata with other citrus types displayed markedly reduced ACC sensitivity compared with C. trifoliata, indicating that this trait is readily overcome through breeding.