Laser-guided variable-rate intelligent spray technology is designed to significantly reduce pesticide use with a positive impact on the environment. However, there have been no reports on applying this technology to commercial fruit farms. Comparative experiments of intelligent variable-rate and conventional constant-rate spray applications for pesticide use and pest control were conducted at a fruit farm in Ohio during two consecutive growing seasons. Apple (Malus pumila), peach (Prunus persica), blueberry (Vaccinium section Cyanococcus), and black raspberry (Rubus occidentalis) were used for the tests. Pest severity of codling moth (Cydia pomonella), oriental fruit moth (Grapholitha molesta), scab (Venturia inaequalis), and powdery mildew (Podosphaera leucotricha) in apple; oriental fruit moth, brown rot (Monilinia fructicola), and powdery mildew (Podosphaera pannosa) in peach; spotted wing drosophila (Drosophila suzukii), mummy berry (Monilinia vaccinii-corymbosi), and phomopsis (Phomopsis vaccinii) in blueberry; and anthracnose (Elsinoe veneta) in black raspberry were assessed. There was equal severity of pests between intelligent and conventional spray applications, whereas the intelligent spray reduced pesticide use by 58.7%, 30.6%, 47.9%, and 52.5% on average for apple, peach, blueberry, and black raspberry, respectively. These results illustrate that intelligent spray technology is more environmentally friendly than conventional standard spray technology and equally or more effective for control of insect and disease pests in fruit production.
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Liming Chen, Matthew Wallhead, Michael Reding, Leona Horst and Heping Zhu
Zhibin Fan, Kai Zhang, Fengyun Wang, Xiaodan Zhao, Ruiqin Bai and Boling Liu
Salvia miltiorrhiza, known as danshen, is one of most valued medicinal plants in China. Although it has been cultivated since ancient times, an optimal culture system needs to be standardized for this important species. Here, we explored the phytochemical properties of S. miltiorrhiza with the treatments of rare earth elements (REEs) to develop an optimal tissue culture system. Four-week-old in vitro-grown S. miltiorrhiza plantlets were used as explants. The experiment was conducted in a randomized block design on a Murashige and Skoog (MS) medium containing 0.2 mg·L−1 naphthaleneacetic acid (NAA) to induce rooting at four different concentrations (50, 100, 200, and 300 μM) of REEs such as cerium (Ce), lanthanum (La), or praseodymium (Pr), respectively. Compared with all REEs at different concentrations, 100 μM Pr induced greater root length than Ce or La at any concentrations. Concomitantly, 0.38 μg tanshinone IIA/mg dry weight (DW) was observed, which was 54.84% higher than in the control. Similarly, chlorophyll content, antioxidant enzyme activity, and secondary metabolite were enhanced in rooting medium supplemented with 100 μM Pr. Therefore, this study showed that 100 μM Pr is an adequate concentration in the optimal culture system for promoting plant growth as well as enhancing secondary metabolite content in S. miltiorrhiza.
Jasmine Jenji Mah, David Llewellyn and Youbin Zheng
One principle for reducing undesirable stem extension in greenhouse production is to counteract the decrease in red-to-far red ratio that occurs naturally during twilight periods. This study evaluated three lighting treatments on the morphology of easter lily (Lilium longiflorum): 1) a 1-hour end-of-day treatment providing 20 μmol·m−2·s−1 of monochromatic red light (EOD R), 2) blackout curtains closed 45 to 75 minutes before sunset and kept closed until 0 to 60 minutes after sunrise (BO), and 3) a control with natural twilight (CTRL). Plants under the BO treatment were 11% shorter than CTRL, while plants exposed to EOD R did not differ in height compared with BO or CTRL. There were no treatment effects on any other measured parameters, including aspects of flowering.
Qin Yang and Yan Fu
Loquat [Eriobotrya japonica (E. japonica)], a small genus of the subtribe Malinae that consists of ≈30 species, is an evergreen rosaceous fruit tree that is native to southeastern China, and some wild species that possess novel, favorable traits have excellent breeding potential. For example, Eriobotrya bengalensis blooms in late spring and ripens in early autumn in Guizhou Province, China, which prevents cold injury in winter by breeding spring-flowering cultivars using the special characters. Therefore, in the present study, the pollination treatments of cut-style pollination were evaluated that may promote successful distant hybridization in Eriobotrya japonica ‘Dawuxing’ × Eriobotrya deflexa and E. japonica ‘Dawuxing’ × E. bengalensis. The results indicated that the impairment of the pollen tube growth in the upper third of the style after pollen germination is an important factor leading to the failure of distant hybridization between the species tested in E. japonica, and that cut-style pollination can effectively overcome prefertilization barriers of the distant hybridization combination. Furthermore, the results of allele-specific polymerase chain reaction (AS-PCR) showed that S-genotypes, in accordance with the S-RNase heredity to separate the rule completely in offspring, should be both parents' S-RNase, and that the random 50 seedlings of Eb-2 and Ed-2 are true hybrids.
Heather Kalaman, Gary W. Knox, Sandra B. Wilson and Wendy Wilber
As land-use patterns change over time, some pollinating insects continue to decline both in abundance and diversity. This is due, in part, to reductions in floral resources that provide sufficient nectar and pollen. Our overall goal is to help increase the use of plants that enhance pollinator health by providing research-based information that is easily accessible to the public. To assess the most successful mode of sharing this information, a survey was distributed to more than 4000 Master Gardener (MG) volunteers of Florida. The objectives of our survey were to gauge both knowledge and interest in common pollinators, common pollinator-friendly floral resources, and a favored means of accessing material about additional pollinator-friendly plants for landscape use. With a response rate of just over 18%, results showed that there is a clear interest among Florida MGs in learning more about pollinators and pollinator-friendly plants with face-to-face classes followed by a website as the preferred modes of accessing educational materials on this topic. Respondents on average were extremely interested in learning more about pollinator plants [mean of 4.41 out of 5.0 (sd = 0.89)], with greatest interest in butterflies/moths (Lepidoptera), followed by bees (Hymenoptera), birds (Aves), bats (Chiroptera), and beetles (Coleoptera). Overall, MG participants felt more confident (P < 0.0001) in their knowledge of pollinator-friendly plants (mean 3.24 out of 5.0) than pollinator insects (mean 3.01 out of 5.0). When tested, 88.5% were able to correctly identify black-eyed susan (Rudbeckia hirta), with 70.1% correctly identifying spotted beebalm (Monarda punctata). Variations were observed in tested knowledge of pollinating insects, with 90.2% correctly identifying a zebra longwing (Heliconius charithonia) and only 32.6% correctly identifying a striped-sweat bee (Agapostemon splendens). These results revealed that MGs perceived themselves to be fairly knowledgeable about both pollinator plants and pollinating insects, yet their tested knowledge ranged widely depending on the actual plant and pollinator type. This suggests an emphasis be given for future MG training focused on diverse plant and pollinator species, preferably in a face-to-face environment. Results also show that additional resources regarding pollinator-friendly plants, as well as identification material on pollinating insects, are both desired and valued by our Florida MG community.
Shuresh Ghimire, Edward Scheenstra and Carol A. Miles
Plastic mulch is commonly used to produce many vegetable crops because of its potential to decrease days to harvest, control weeds, and improve soil moisture conservation. However, use of plastic mulch is relatively new for sweet corn (Zea mays L.) in North America. We compared five plastic soil-biodegradable mulches [BDMs; Bio360, Organix AG, Clear Organix AG, Naturecycle, and Experimental polylactic acid/polyhydroxyalkanoates (Metabolix, Inc., Cambridge, MA)] and a paper mulch (WeedGuardPlus) against standard black polyethylene (PE; nonbiodegradable) mulch and bare ground cultivation for growth, yield, and quality of sweet corn cultivar Xtra Tender 2171. This field experiment was carried out in Mount Vernon, WA, which has a Mediterranean-type climate with an average air temperature of 16.1 °C during the 2017 and 2018 growing seasons. The experiment was drip irrigated; and in both years, preemergence herbicides were applied to the entire experimental area 1 to 2 days after seeding, and post-emergence herbicides were applied to alleys. While most mulches remained intact until the end of the growing season, Clear Organix AG started to split shortly after laying, resulting in significant weed pressure by midseason in both 2017 and 2018. Plant height toward the end of the season was lowest for plants grown on bare ground, intermediate for Clear Organix AG and WeedGuardPlus, and highest for the black plastic BDM and PE mulch treatments both years, except for Bio360 in 2018 where plant height was intermediate. Days to 50% tasseling and 50% silking were delayed 9 and 13 days, respectively, for bare ground and WeedGuardPlus compared with all other treatments in both years. Marketable ear yield was highest with the black plastic BDMs and PE mulch and lowest with bare ground, WeedGuardPlus, and Clear Organix AG treatments in both years. Total soluble solid content of kernels, and length and diameter of ears grown on the plastic BDM and PE mulch treatments were equal to or greater than, but never lower than, bare ground and WeedGuardPlus. These results indicate that growth, yield, and quality of sweet corn grown with black plastic BDMs are comparable to PE mulch, making black plastic BDMs an effective alternative to black PE mulch for sweet corn production in a Mediterranean-type climate.
Job Teixeira de Oliveira, Rubens Alves de Oliveira, Lucas Allan Almeida Oliveira, Paulo Teodoro and Rafael Montanari
Among the crops that are usually grown under irrigation, one can mention garlic, which is a product with high demand in Brazil and the world, it is highly valued in the cuisine of several countries, and is an aggregated crop with high economic value. In 2018, this work was conducted in Yellow Red Latosol. The objective was to characterize the structure and magnitude of the spatial distribution of garlic production components and to map the productive components to visualize spatial distribution and to evaluate the spatial correlation between garlic bulb yield (BY) and other variables of the crop: total plant mass (TPM), number of leaves (NL), floral tassel length (FTL), leaf length (LL), leaf width (LW), pseudostem diameter (PD), shoot wet mass (SWM), shoot dry mass (SDM), number of cloves per bulb (NCB), clove mass (CM), root dry mass (RDM), and irrigation (IRR). All these traits were sampled in a 90-point grid georeferenced. Data analysis using statistical and geostatistical techniques made it possible to verify that the production components and BY, TPM, NL, FTL, LL, LW, PD, SWM, SDM, CM, and IRR presented special dependence. The spatial correlation between BY and TPM, LW, and CM showed a moderate spatial dependence.
Michael J. Havey
The most common bulb colors of onion (Allium cepa) are red, yellow, and white; chartreuse is a relatively rare bulb color conditioned by the homozygous recessive genotype at the G locus. In this research, plants with chartreuse bulbs were crossed with inbreds with yellow bulbs to develop segregating families for genetic mapping of the G locus. For all of 17 F2 families, segregations for yellow vs. chartreuse bulbs fit the expected 3:1 ratio (P > 0.05). DNAs were isolated from one F2 family and genotyped for single nucleotide polymorphisms (SNPs) to produce a genetic map of the G locus and 380 SNPs, of which 119 SNPs have not been previously mapped. Segregations for yellow vs. chartreuse bulbs placed the G locus at the end of chromosome 7 at 6.7 cM from the nearest SNP (isotig28625_2789). This codominant SNP marker linked to the G locus should be useful for introgression of recessive chartreuse bulb color into diverse onion populations for commercial production of this uniquely colored onion.
Charles Fontanier, Justin Quetone Moss, Lakshmy Gopinath, Carla Goad, Kemin Su and Yanqi Wu
Cell and plastid membranes play a critical role in plant response to chilling stress. Fall color retention (chilling tolerance) of bermudagrass (Cynodon sp.) is known to vary with cultivar and management practices. A growth chamber study was conducted to characterize the lipid composition of three bermudagrasses in response to chilling stress. The grasses selected were ‘Tahoma 31’ (chilling-sensitive) and ‘Tifway’ (chilling-tolerant) interspecific hybrid bermudagrass (C. dactylon × C. transvaalensis) and ‘Celebration’ common bermudagrass (C. dactylon), which served as an internal standard. Plants were subjected to simulated fall conditions defined as an 8/2 °C (day/night) temperature regime with 10-hour photoperiod and evaluated for chilling response for 42 days before allowing plants to enter an apparent dormancy. Plant leaves were sampled for lipidomics analysis at 0, 14, and 42 days of chilling treatment (DOT) and again after 40 days of recovery from dormancy (during which temperatures were adjusted to mimic average spring conditions for Oklahoma). ‘Tifway’ demonstrated the lowest electrolyte leakage (EL) and visual discoloration at 42 DOT, while ‘Tahoma 31’ had the greatest EL and discoloration on the same date, and ‘Celebration’ was intermediate of the two. Prolonged exposure to chilling stress generally increased digalactosyldiacylglycerol and phosphatidylcholine (PC) content and decreased monogalactosyldiacylglycerol (MGDG) content, with ‘Tahoma 31’ showing the greatest increase in PC and decrease in MGDG. The double bond index, an indicator of fatty acid unsaturation, was greatest in ‘Tifway’ at 42 DOT. Each cultivar increased in fatty acid unsaturation, with Tifway demonstrating the greatest increase in MGDG unsaturation. Multivariate discriminant analysis identified six individual lipid species that contributed most to the cultivar response to chilling. These findings suggest unsaturation level of plastid lipids, particularly MGDG, is important for chilling tolerance and therefore fall color retention of bermudagrass. Furthermore, this study provides evidence that chilling tolerance can be negatively associated with freezing tolerance in bermudagrass.
William G. Hembree, Thomas G. Ranney, Nathan P. Lynch and Brian E. Jackson
The genus Deutzia, in the Hydrangeaceae family, includes ≈60 species that range in ploidy from diploid (2x) to tetradecaploid (14x). There have been extensive breeding efforts for Deutzia, but this has been limited to a few parental species. Although there have been numerous studies of the cytogenetics of some species of Deutzia, the ploidy level of many species remains unknown, and there are few cytogenetic data available for Deutzia hybrids and cultivars. The purpose of this study was to validate the identification and determine the genome sizes and ploidy of a diverse collection of Deutzia species and hybrids using cytology and flow cytometry. Accessions were identified using the most current taxonomic key and voucher specimens were deposited for each at the North Carolina State University herbarium. Corrected and updated species names are provided for all cultivars and accessions studied. Traditional cytology was performed for roots of representative taxa to calibrate the genome size with the ploidy level. The genome size and estimated ploidy were determined for 43 accessions using flow cytometry. Ploidy levels were reported for the first time for three species of Deutzia including D. calycosa (2n = 4x = 52), D. paniculata (2n = 4x = 52), and D. glauca (2n = 12x = 156). The base and monoploid genome size (1Cx) were somewhat variable and ranged from 1.20 to 2.05 pg. No anisoploid hybrids were documented, suggesting the presence of an interploid block. The information produced from this study are beneficial to future curation, research, development, and improvement of this genus with corrected nomenclature and clone-specific data regarding cytogenetics.