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Open access

Yun Kong, Xiangyue Kong and Youbin Zheng

Nondestructive estimation of individual shoot fresh weight (FW) from its measurable morphological traits is useful for a wide variety of purposes in pea shoot production. To predict individual shoot FW, nine regression models in total were developed, including two power models using stem diameter (SMD) or stem length (SML) as a variable, and seven linear models using part or all the following variables: SMD, SML, leaflet length (LL), leaflet width (LW), stipule length (SEL), and stipule width (SEW). Among the nine models, the 6-variable linear equation had the highest coefficient of determination, R 2 = 0.92, indicating it is most effective at explaining the variation in FW. The linear equations including only one variable, SMD or SML, were equally the least effective as nonlinear equations (i.e., power models). This finding suggests that there was a linear rather than nonlinear relationship between FW and the morphological variables. During stepwise regression, SEW and LW together were first removed from the 6-variable linear models without reducing the R 2, and then SEL, SMD, SML were further removed one-by-one, which reduced the R 2 from 0.92 to 0.90, 0.85, and 0.71, respectively. The result suggests that SMD, SML, SEL, and LL were the most important four predictor variables for multivariable linear regression models to estimate FW, an idea that was also supported by path analysis. For the four linear models with 1–4 predictor variables from stepwise regression, the prediction accuracy of FW was evaluated based on the agreement between the predicted and measured values using another independent dataset. The 4- and 3-variable linear models (i.e., FW = −1.437 + 0.276 SMD + 0.010 SML + 0.022 LL + 0.013 SEL and FW = −1.383 + 0.308 SMD + 0.011 SML + 0.030 LL, respectively) were selected for their more accurate prediction than 1- and 2-variable linear models and relatively simpler forms than a 6-variable linear model. Although the prediction accuracy can be potentially affected by air temperature, light conditions, and harvesting time, the multilinear regression model is an effective approach for estimating fresh weight of individual pea shoots using its measurable morphological traits.

Open access

Qirui Cui, Haizheng Xiong, Yufeng Yufeng, Stephen Eaton, Sora Imamura, Jossie Santamaria, Waltram Ravelombola, Richard Esten Mason, Lisa Wood, Leandro Angel Mozzoni and Ainong Shi

Cowpea [Vigna unguiculate (L.) Walp.] is not only a healthy, nutritious, and versatile leguminous crop; it also has a relatively high adaptation to drought. Research has shown that cowpea lines have a high tolerance to drought, and many of them can survive more than 40 days under scorching and dry conditions. The cowpea (Southern pea) breeding program at the University of Arkansas has been active for more than 50 years and has produced more than 1000 advanced breeding lines. The purpose of this study was to evaluate the drought-tolerant ability in Arkansas cowpea lines and use the drought-tolerant lines in cowpea production or as parents in cowpea breeding. A total of 36 University of Arkansas breeding lines were used to screen drought tolerance at the seedling stage in this study. The experiment was conducted in the greenhouse using a randomized complete block design (RCBD) with two replicates, organized in a split-plot manner, where the drought treatment (drought and nondrought stress) as the main plot and the cowpea genotypes as the subplot. Drought stress was applied for 4 weeks, and three drought-tolerant–related traits were collected and analyzed. Results showed that cowpea breeding lines: ‘17-61’, ‘17-86’, ‘Early Scarlet’, and ‘ARBlackeye #1’ were found to be drought tolerant.

Open access

Mingyue Bao, Minmin Liu, Qingxia Zhang, Tonglin Wang, Xia Sun and Jinguang Xu

Herbaceous peony (Paeonia lactiflora Pall.) is a well-known ornamental plant with abundant flower colors. However, our understanding of the underlying mechanisms of flower color formation is limited. In this study, a wild sample of herbaceous peony (collected from Heze, China) and eight cultivars with different colors were selected for experimental investigation. The Royal Horticultural Society Color Chart was used to determine flower color, and the anatomic structure; cell sap pH value; moisture content (MC); condensed tannin content (Ct); soluble sugar and soluble protein content of the petals; and content and composition of anthocyanin, flavonoids, and carotenoids in the petals were examined. 1) In the white, pinkish white, pale purple, purplish pink, and reddish purple cultivars, deeper color was associated with greater total amounts of anthocyanin (TA). Hypochromic effects were observed for kaempferol-7-O-glucoside (Km7G), myricetin-3-rhamnoside (My3R), and luteolin-7-O-glucoside (Lu7G). The accumulation of quercetin-3-O-glucoside (Qu3G) and lutein affected yellow color formation in the petals. 2) There are papillate epidermal cells in the petals of the wild P. lactiflora sample, ‘Lanyucangjin’, and ‘Dongjingnvlang’. 3) Cell sap pH and MC of the petals of white, pinkish white, pale purple, and purplish pink cultivars were greater than those of the purplish red and most of the reddish purple cultivars. 4) The Ct was greatest in the purplish red cultivars, whereas no condensed tannins were detected in the white, pinkish white, and pale purple cultivars. 5) There were no significant correlations among soluble sugar content, soluble protein content, and the other physiological indications.

Open access

Li-Chun Huang

As social media penetration has reached more than half of the eligible populations for most of the countries in the world, many florists are thinking of ways of converting their social media fan base into a virtual brand community that can bring numerous benefits to the florists. As relevant topics are rarely investigated in the academic domain of floriculture, this study seeks to address this deficiency. The objectives of this study were 1) to examine the possibility of converting the florists’ social media fan base into a virtual brand community, and 2) to investigate the influence of users’ knowledge of and personal experience with the florist on the formation of the florists’ social media–based brand communities, as well as the subsequent influence on the florists’ brand equity. The statistical results of the descriptive statistical analysis and structural equation modeling (SEM) indicate that the florists’ social media fan base has revealed the markers of brand communities, demonstrating the potential that exists for building the florists’ virtual brand communities from their social media fan base. These statistical results also show that the users’ knowledge of the florist is one of the key elements assisting in the conversion of the florist’s fan base into a virtual brand community for the florist, and subsequently enhances the users’ commitment toward the florist’s brand. Even though the influence of the users’ personal experience with the florist on the formation of the florist’s social media–based brand community is not proved, it is found to be highly correlated with the users’ knowledge of the florist. Based on the study’s findings, strategies for driving the formation of florists’ social media–based brand communities are also provided.

Open access

Darab Hassani, Mohammad Reza Mozaffari, Asghar Soleimani, Raana Dastjerdi, Reza Rezaee, Mansureh Keshavarzi, Kourosh Vahdati, Ahmad Fahadan and Jamal Atefi

Open access

Pinki Devi, Scott Lukas and Carol A. Miles

Splice grafting with both cotyledons removed from the rootstock may significantly increase watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] grafting efficiency, eliminate rootstock regrowth, and reduce costs of watermelon transplant production. We evaluated the efficacy of antitranspirant and sucrose treatments on the survival of splice-grafted transplants and assessed the effects of grafting method and rootstocks on fruit yield and quality. First, in a greenhouse experiment, four commercial antitranspirants, applied to rootstock seedlings before splice grafting, increased transplant survival 21 days after grafting (DAG) from 7% to 35% to 68% (P < 0.0001). In a second greenhouse experiment, survival of splice-grafted seedlings was 91% for plants that received 2% sucrose solution + antitranspirant, compared with 67% for plants receiving 2% sucrose alone and 25% for plants that received only water (P < 0.0001). Finally, in a field experiment we compared splice- vs. one-cotyledon grafting with two rootstocks (‘Shintosa Camelforce’ and ‘Tetsukabuto’) vs. nongrafted plants. At 54 days after transplanting (DAT), survival of all grafted transplants averaged 96% with a plant vigor rating of 7.7/10 (10 = most vigorous), compared with 84% survival (5.8/10 vigor rating) for nongrafted transplants. Flowering was delayed by an average of 2 days for splice-grafted watermelon (37 DAT) vs. one-cotyledon grafted and nongrafted plants (P < 0.0001), but harvest date was the same for all treatments (70 DAT). Fruit were harvested 0, 7, and 14 days after fruit reached physiological maturity, and there was no difference in total yield or fruit quality between grafted and nongrafted treatments, with two exceptions. Fruit with splice-grafted ‘Shintosa Camelforce’ rootstock had the firmest flesh (8.2 N) compared with nongrafted transplants (5.3 N), and lycopene increased from 16.7 µg·g−1 at physiological maturity to as high as 31.4 µg·g−1 when harvested 7 days after physiological maturity (P = 0.0002). These results indicate that application of sucrose with antitranspirant to rootstock seedlings before grafting can increase the survival of splice-grafted watermelon, and splice-grafted watermelon perform similarly to one-cotyledon grafted and nongrafted watermelon plants in field production.

Open access

Qing Shen, Hua Bian, Hai-yan Wei, Li Liao, Zhi-yong Wang, Xiao-yan Luo, Xi-peng Ding, Zhenbang Chen and Paul Raymer

Seashore paspalum (Paspalum vaginatum) is an important warm-season turfgrass distributed in tropical and coastal areas. It has excellent resistance to abiotic stresses, such as salinity, drought, and low temperature. However, the research on genetic diversity of local P. vaginatum collections from China is limited. In this study, the genetic diversity among 58 P. vaginatum accessions from four different provinces in China and four cultivars were assessed using simple sequence repeat (SSR) markers. The results indicated that a total of 45 alleles were detected by 19 polymorphic markers, with a range of 2 to 4 and an average of 2.4 alleles per marker. The genetic similarity coefficients between each pair of the 58 P. vaginatum accessions and four cultivars ranged from 0.51 to 1.00, with an average of 0.77. The range of variation of Shannon diversity index of each SSR marker was 0.047 to 1.075, with an average of 0.486. The polymorphic information content of each SSR marker varies from 0.016 to 0.577, with an average of 0.249. The results of cluster analysis and principal component analysis (PCA) showed that 58 P. vaginatum accessions and four cultivars were divided into four groups. These results provide the theoretical basis for the genetic diversity assessments and molecular marker–assisted breeding of P. vaginatum species.

Open access

Yunmi Park, Seok-Woo Lee, Soon-ho Kwon and Hae Yun Kwon

Open access

Hanan M. El-Hoseiny, Mohamed N. Helaly, Nabil I. Elsheery and Shamel M. Alam-Eldein

Mango production faces several challenges, such as nutrient deficiency, physiological stress, and alternate bearing, which eventually affect tree productivity. This study was carried out during the 2017 and 2018 seasons to evaluate the effect of single and combined applications of humic acid (as potassium humate; 0.15%, 0.30%, 0.45%) and boron (as boric acid; 300, 600 mg·L−1) on ‘Zebda’ mango trees grown at Dir AlMalak region, Sharkeya Governorate, Egypt. Foliar spray was applied twice before flowering (first week of January and first week of February), and a third spray was applied by the beginning of flowering (first week of March) in both seasons. Humic acid and boron effectively enhanced tree growth, flowering, yield, and fruit quality. Humic acid was more effective than boron in this respect. Combined application of both materials surpassed the single application of each material on overall tree physiology and annual productivity. The observed results may be a consequence of the increase in tree photosynthetic pigments, nutrients, organic solutes, and phytohormones such as auxins, gibberellins, and cytokinins. The reduction in abscisic acid content may be related to the role of humic acid and boron protecting the plant against destructive oxidative reactions; improving the ability of the trees to withstand environmental stresses; thereby reduce floral malformation percentage, minimize the incidence of alternate bearing, and improve annual tree productivity and fruit quality. The most pronounced effect in this regard was noted with the application of 0.30% humic acid + 600 mg·L−1 boric acid.

Open access

Matthew A. Cutulle, H. Tyler Campbell, Monica Farfan and Phillip A. Wadl

Weed management is an important component of sweetpotato production. Currently, S-metolachlor is the only herbicide registered in sweetpotato that has some suppressive effect on nutsedge species (Cyperus spp.). It is integral that the release of any new germplasm from sweetpotato breeding programs be tolerant to S-metolachlor. Screening for thousands of experimental clones for S-metolachlor in a field trial would be cumbersome. Therefore, screening for tolerant lines might be streamlined in an hydroponics system. Research was conducted to determine whether a hydroponics assay could detect differences in S-metolachlor response between a known sensitive sweetpotato cultivar (Centennial) and a tolerant sweetpotato cultivar (Beauregard) in 10 days. Results of the study show that ‘Beauregard’ was ≈50 times more tolerant to S-metolachlor than ‘Centennial’ when accessing injury at the 25% threshold. No differences were detected in S-metolachlor response between cultivars in the soil-based assay. This assay could be used for screening for S-metolachlor tolerance in a sweetpotato breeding program.