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Open access

Grant L. Thompson, Cynthia L. Haynes, and Samantha A. Lyle

High-resolution scans of plant cuttings were made for a plant identification course to create additional study resources. Stems, flowers, leaves, and other parts with identifiable features were cut and placed on a high-quality flatbed scanner. A framework suspended a black background cloth above the cuttings to create a dark scanning environment, and it was placed far enough away from the scanner glass so as not to appear in the scanned image. Botanical scans can be shared, manipulated, composed, and otherwise provided to students for study materials. Scans are complementary to other common study aids such as pressed herbarium samples or photography.

Open access

Gursewak Singh, William Patrick Wechter, Bhupinder Singh Farmaha, and Matthew Cutulle

Anaerobic soil disinfestation (ASD) is a preplant pest management technique that involves amending the soil with a labile carbon source, irrigating the soil to stimulate decomposition, and then covering the soil with polyethylene film (polyfilm) to limit gas exchange. During the ASD process, soil microorganisms shift from aerobic to anaerobic metabolism and release phytotoxic byproducts such as organic acids and gases. Although it has been shown that these phytotoxic by-products have a negative impact on weed survival, questions remain about whether commercial-level weed control can be achieved using ASD alone or in combination with other chemicals. Greenhouse and field studies were conducted to evaluate ASD with mustard (Brassica sp.) meal, molasses, and herbicide applications for yellow nutsedge (Cyperus esculentus) control in tomato (Solanum lycopersicum). The treatments in these studies included factorial of two carbon sources [mustard meal + molasses (MMM) or no carbon amendment], three herbicide treatments [halosulfuron applied preemergence (PRE), halosulfuron applied postemergence (POST), and no herbicide] and two polyfilm treatments (polyfilm cover or polyfilm uncover). In field trials two polyfilm cover treatments were punctured and nonpunctured. Soil treatments included molasses at 14,000 L·ha−1 and mustard meal at 2100 kg·ha−1. Halosulfuron was applied at a rate of 1 oz/acre for PRE or POST applications. Greater anaerobic conditions were achieved in polyfilm cover treatments amended with MMM. In greenhouse and field trials, the most effective treatments for reducing yellow nutsedge populations were ASD with MMM or combined with halosulfuron application (PRE- or POST-ASD), which delivered significantly higher weed control than all other treatments tested or controls. In field trials, ASD with MMM caused plant growth stunting 14 d after transplantation (DAT); however, plants recovered, and stunting or injury was often not observed at 42 DAT. These studies demonstrated that ASD using MMM can be an effective strategy for reducing yellow nutsedge populations; however, the more research is needed to ensure crop safety while using ASD technology.

Open access

Jeb S. Fields, Kristopher S. Criscione, and Ashley Edwards

Substrate stratification is an emerging substrate management strategy involving layering multiple substrate materials within a single container to modify physiochemical characteristics of the substrate system. Specifically, stratifying allows growers and researchers to rearrange the air–water balance within a container to modify hydraulic characteristics. Moreover, fertilizer can be incorporated into just the upper strata to reduce leaching. Research to date has shown benefits associated with resource efficiency, production timing, and weed control. With the associated benefits for substrate stratification, interested growers will need pragmatic solutions for onsite trials. Therefore, the objective of this study was to identify a cost-effective solution for growers interested in exploring stratification options. As such, this research was designed to identify a single-screen bark separation to generate fine and coarse bark textures suitable for use as the top and bottom substrate strata. Loblolly pine bark (Pinus taeda) was screened with either a 4.0-mm, 1/4-inch, or 3/8-inch screen, with the particles passing through the screen (unders) separated from retained particles (overs). Stratified substrate systems were engineered with an individual screen wherein the fines were layered atop the coarse particles from the same screen. ‘Natchez’ crepe myrtle (Lagerstroemia indica) liners were planted in either of the three stratified substrate treatments or a nonstratified control. Substrate physical characteristics were assessed for each strata by pre- and postproduction properties to identify changes of substrate. The final growth index of the crop was unaffected by the substrate treatment (P = 0.90); however, stratified substrates did increase dry root weight (P = 0.02), with the smallest screen (4.0 mm) resulting in the greatest root weight. Separation of roots between the two strata indicated the presence of more roots in the upper strata in all substrates. However, the stratified substrates resulted in a greater shift in root location, encouraging increased rooting in the upper strata with fine particles, with the largest screen (3/8 inch) resulting in the greatest differentiation between upper and lower rooting. Each stratified treatment had increase in water-holding capacity in the lower (coarser) strata without changes in the upper strata. Thus, we conclude that single screens can be used to build stratified substrate systems. Moreover, screen aperture size may be used to achieve different outcomes with regard to root growth and development as well as water–air balance. Further research may indicate that screen selection may be used to target specific crop needs.

Open access

Xinpeng Zhang, Zongda Xu, Wenli Wang, Deyu Mu, Xiang Meng, Min Lu, and Cheng Li

Plants with the flower color phenotype of double-color flowers are very precious and attractive and can usually be regarded as valuable germplasm resources for studying and improving flower color. This paper summarizes the coloring mechanism of double-color flowers in plants from three aspects: the formation of double-color flowers, the physiological factors affecting the coloring difference of double-color flowers, and the molecular mechanism affecting the coloring difference of double-color flowers, to provide a theoretical reference for the in-depth study of the coloring mechanism and molecular breeding of double-color flowers in the future.

Open access

Young-Sik Park, Je-Chang Lee, Nam-Yong Um, Haet-Nim Jeong, and Jae-Yun Heo

In Korea, ‘Campbell Early’, ‘Shine Muscat’, and ‘Kyoho’ account for more than 90% of the Korean grape cultivation area (Kim et al., 2021). As a result, the supply of grapes in the Korean market is excessive during a certain period. Consequently, it is difficult to avoid a reduction in the wholesale price, and the opportunity for consumers to experience other grape cultivars becomes limited. In the current scenario, in which imports are occurring rapidly following the recent implementation of the free-trade agreement with Chile and the United States, it is necessary to cultivate various high-quality grape cultivars to

Open access

Shoufu Gong, Bailing Miao, and Xiangxiang Dong

Gardenia jasminoides, belonging to the Rubiaceae family, is widely distributed and planted in China. It has traditionally been used as an ornamental and medicinal plant in several Asian countries. The rapid development of high-throughput sequencing technology makes it feasible to obtain complete chloroplast (cp) genome sequences and will deepen our understanding of evolution of G. jasminoides. In this study, we sequenced the complete cp genomes of two botanical varieties of G. jasminoides. The complete cp genomes of both botanical varieties of G. jasminoides showed highly conserved structures and the length was 154,954 base pairs (bp) for G. jasminoides var. radicans (GJR) and 155,098 bp for G. jasminoides var. grandiflora (GJG). A total of 132 and 133 genes were identified in GJR and GJG, respectively. The cp genomes of two newly sequenced G. jasminoides were further compared with two published G. jasminoides cp genomes. Multiple repeats and simple sequence repeats (SSRs) were detected among different genotypes of G. jasminoides. The intron sequences of rps16 and rpl16 genes were slightly divergent among four genotypes of G. jasminoides. Phylogenetic analyses based on the complete cp genome sequences showed that G. jasminoides was closely associated with Fosbergia shweliensis, with Coffea as their close relative. Taken together, the complete cp genomes of GJG and GJR provided significant insights and important information that can be used to identify related species and reconstruct their phylogeny.

Open access

S. Brooks Parrish and Zhanao Deng

Cultivated caladium (Caladium × hortulanum; 2n = 2x = 30) is an important ornamental aroid for the environmental horticulture industry. A better understanding of its genetic diversity is needed for continued improvement of caladium. The caladium germplasm maintained in the University of Florida’s caladium breeding program were surveyed for potential variation in chromosome number and nuclear DNA content to gain a better understanding of caladium genetic diversity at the cytogenetic level. For the first time caladium triploidy was discovered in two breeding lines, UF-15-414 and UF-4407 with 2n = 3x = 45 chromosomes and a nuclear DNA content of 13.86 pg·2C−1. In addition, a new chromosome number (2n = 2x = 34) was found in one cultivar, ‘White Wing’. Compared with their diploid parents or grandparents, the triploids showed a distinct, attractive leaf morphology with rounder and thicker leaves. The pollen stainability of UF-15-414 and UF-4407 was 63% and 73%, respectively, indicating potential male fertility, which was unexpected. Analysis of simple sequence repeat (SSR) marker banding patterns confirmed that UF-15-414 was a direct progeny of UF-4407 through hybridization with the diploid cultivar Aaron, whereas UF-4407 might result from fusion of an unreduced (female or male) gamete with a reduced gamete. Chromosome counting and SSR marker analysis of ‘White Wing’ and its progeny cultivars ‘White Wonder’ and ‘White Delight’ suggested that ‘White Wing’ possibly transmitted its 34 chromosomes to progeny during sexual reproduction. The discovery and characterization of these triploids revealed the occurrence of natural sexual polyploidization in caladium and indicated good potential for creating and selecting new triploids for future caladium breeding. The observed new chromosome number in ‘White Wing’ and its progeny cultivars implies that other chromosome variations may be present among cultivated caladiums. In summary, these results revealed two male-fertile triploid caladiums and a new chromosome number that can enrich the cytogenetic diversity in future caladium cultivar development.

Open access

Masaru Homma, Takafumi Watabe, Dong-Hyuk Ahn, and Tadahisa Higashide

We investigated the relationships among the fruit set, dry matter production, and source-to-sink ratio of sweet pepper (Capsicum annuum) plants grown in a greenhouse. We quantified daily fruit sink strength per stem (st) at m days after transplanting (SSTm_st) by modeling the fruit growth curve. The daily total dry matter production (TDMm_st) was calculated and defined as the source strength. During an experiment lasting ≈250 days, the fruit set ratio [number of fruit harvested/number of flowers (FSRm)] decreased significantly with increases in both the weekly average SSTm_st from 9 days before anthesis (DBA) to 13 days after anthesis (DAA) and the weekly average fruit number (FRNm_st) from 9 to 1 DBA. FSRm increased significantly with increases in both the weekly average TDMm_st from 1 to 13 DAA and the weekly average source-to-sink ratio [source strength/fruit sink strength (SSRm_st)] from 5 DBA to 13 DAA. During the whole experimental period, significant positive correlations with FSRm were observed for TDMm_st and SSRm_st, and significant negative correlations with FSRm were observed for SSTm_st and FRNm_st. FSRm increased until approximately the time when the weekly average SSRm_st at 1 to 7 DAA (anthesis to 156°C⋅d−1) ranged from 1.0 to 4.0; then, it showed a saturation curve at SSRm_st values more than 4.0 (R 2 = 0.81). These results suggest that it is possible to moderate the fluctuations in sweet pepper yield by monitoring the SSRm_st and the number of fruit set.

Open access

Chia Ting Han, Yu Sung, and Ming-Tung Hsueh

Seeds of some winged bean varieties have low germination due to the presence of water-impermeable hardseeds. Seeds of ‘Taitung No.1’ winged bean had only 31% germination because the remaining 69% of seeds had a water-impermeable seedcoat. Sandpaper abrasion and sulfuric acid immersion for 15 and 25 min effectively removed hardseededness of the seeds, resulting in more than 89% germination. As seed moisture content (MC) decreased from 14.8% to 7%, the percentage of seeds with a water-impermeable seedcoat increased. Seed lots with 14.8%, 11%, 9%, and 7% MC had 7%, 38%, 56%, and 78% of hardseeds, respectively, on day 7 in the germination test. It was found that the hilum was responsible for water loss from the whole seed, and the seedcoats began to become water-impermeable at 12% MC. The lens and micropylar regions were initial water entry sites in the Vaseline-blocking experiment.