Enhancing citrus fruit yield investigations through flight height optimization with UAV imaging.

Citrus fruit yield is essential for market stability, as it allows businesses to plan for production and distribution. However, yield estimation is a complex and time-consuming process that often requires a large number of field samples to ensure representativeness. To address this challenge, we investigated the optimal altitude for unmanned aerial vehicle (UAV) imaging to estimate the yield of Citrus unshiu fruit. We captured images from five different altitudes (30 m, 50 m, 70 m, 90 m, and 110 m), and determined that a resolution of approximately 5 pixels/cm is necessary for reliable estimation of fruit size based on the average diameter of C. unshiu fruit (46.7 mm). Additionally, we found that histogram equalization of the images improved fruit count estimation compared to using untreated images. At the images from 30 m height, the normal image estimates fruit numbers as 73, 55, and 88. However, the histogram equalized image estimates 88, 71, 105. The actual number of fruits is 124, 88, and 141. Using a Vegetation Index such as IPCA showed a similar estimation value to histogram equalization, but I1 estimation represents a gap to actual yields. Our results provide a valuable database for future UAV field investigations of citrus fruit yield. Using flying platforms like UAVs can provide a step towards adopting this sort of model spanning ever greater regions at a cheap cost, with this system generating accurate results in this manner.

Identification of new cold tolerant Zoysia grass species using high-resolution RGB and multi-spectral imaging.

Zoysia grass (Zoysia spp.) is the most widely used warm-season turf grass in Korea due to its durability and resistance to environmental stresses. To develop new longer-period greenness cultivars, it is essential to screen germplasm which maintains the greenness at a lower temperature. Conventional methods are time-consuming, laborious, and subjective. Therefore, in this study, we demonstrate an objective and efficient method to screen maintaining longer greenness germplasm using RGB and multispectral images. From August to December, time-series data were acquired and we calculated green cover percentage (GCP), Normalized Difference Vegetation Index (NDVI), Normalized Difference Red Edge Index (NDRE), Soil-adjusted Vegetation Index (SAVI), and Enhanced Vegetation Index (EVI) values of germplasm from RGB and multispectral images by applying vegetation indexs. The result showed significant differences in GCP, NDVI, NDRE, SAVI, and EVI among germplasm (p < 0.05). The GCP, which evaluated the quantity of greenness by counting pixels of the green area from RGB images, exhibited maintenance of greenness over 90% for August and September but, sharply decrease from October. The study found significant differences in GCP and NDVI among germplasm. san208 exhibiting over 90% GCP and high NDVI values during 153 days. In addition, we also conducted assessments using various vegetation indexes, namely NDRE, SAVI, and EVI. san208 exhibited NDRE levels exceeding 3% throughout this period. As for SAVI, it initially started at approximately 38% and gradually decreased to around 4% over the course of these days. Furthermore, for the month of August, it recorded approximately 6%, but experienced a decline from about 9% to 1% between September and October. The complementary use of both indicators could be an efficient method for objectively assessing the greenness of turf both quantitatively and qualitatively.

Implication of high variance in germplasm characteristics.

The beauty of conserving germplasm is the securement of genetic resources with numerous important traits, which could be utilized whenever they need to be incorporated into current cultivars. However, it would not be as useful as expected if the proper information was not given to breeders and researchers. In this study, we demonstrated that there is a large variation, both among and within germplasm, using a low-cost image-based phenotyping method; this could be valuable for improving gene banks' screening systems and for crop breeding. Using the image analyses of 507 accessions of buckwheat, we identified a wide range of variations per trait between germplasm accessions and within an accession. Since this implies a similarity with other important agronomic traits, we suggest that the variance of the presented traits should be checked and provided for better germplasm enhancement.

From crop specific to variety specific in crop modeling for the smart farm: A case study with blueberry.

Facility cultivation has been evolved from greenhouses to smart farms using artificial intelligence (AI) that simulates big data to maximize production. However, the big data for AI in smart farm is not studied well; the effect of differences among varieties within a crop remains unclear. Therefore, the response of two varieties of blueberry, 'Suziblue' and 'Star', to light was tested using SAPD meter in order to demonstrate the environmental responses could be different among varieties within the same species. The results showed that those two varieties had significant differences in SPAD values based on the leaf's position and time, whereas 'Star' did not. This indicates that the effect of light depends on the variety, which implies that other traits and other crops may show similar differences. These results are based on a simple experiment. However, it is enough to elucidate that it is extremely important to characterize responses to the environment not only for each crop but also for each variety to collect data for smart farming to increase accuracy for modeling; consequently, to maximize the efficiency of these facilities.

SPAD: potential phenotyping method for characterization of blueberry.

BACKGROUND: Blueberry is an attractive fruit due to its blue or purple-colored pigments with effective anti-cancer and anti-inflammatory properties. Accordingly, the demand for blueberry cultivation is rapidly increasing. However, various cultivars from different regions are cultivated without characterizing it. METHODS AND RESULTS: We present a method to characterize crops using the SAPD meter. For characterizing each cultivar, the photosynthetic potential of each cultivar, which was measured by SAPD meter three times a day at three heights of a crop, was compared under the same conditions. CONCLUSION: A difference in photosynthetic potential even in the same SHB-type cultivars was found. Therefore, applying cultivation methods suitable to the characteristics of each cultivar is necessary. At the same time, it would be meaningful for researchers and breeders to use this method for genome-wide association study in order to develop molecular markers for increasing photosynthesis efficiency.

Potential Use of Colored LED Lights to Increase the Production of Bioactive Metabolites Hedyotis corymbosa (L.) Lam.

Hedyotis corymbosa (L.) Lam is a wild herb that is used in traditional Indian, Chinese, and African medicine. Light-emitting diode (LED) technology is paving the way to enhance crop production and inducing targeted photomorphogenic, biochemical, or physiological responses in plants. This study examines the efficiency of H. corymbosa (L.) Lam production under blue 450 nm and red 660 nm LED lights for overall plant growth, photosynthetic characteristics, and the contents of metabolite compounds. Our research showed that blue LED lights provided a positive effect on enhancing plant growth and overall biomass. In addition, blue LED lights are more effective in controlling the production of sucrose, starch, total phenolic compounds, and total flavonoid compared to red LED lights. However, blue and red LED lights played essential but different roles in photosynthetic characteristics. Our results showed the potential of colored LED light applications in improving farming methods and increasing metabolite production in herbs.

Antifungal Activity of Thymol against Aspergillus awamori and Botrytis aclada Isolated from Stored Onion Bulbs.

The antifungal activity of thymol against Aspergillus awamori F23 and Botrytis aclada F15 in onions was examined through direct treatment with amended media and gaseous treatment with I-plates (plastic plates containing central partitions). The protective and curative control efficacy of thymol was examined 24 h before and after the inoculation of onion bulbs with the fungal isolates. Mycelial growth, sporulation, and spore germination of the isolates were inhibited on potato dextrose agar amended with various concentrations of thymol or acetic acid (positive control). Overall, thymol produced a stronger inhibitory effect on the mycelial growth and development of the isolates than acetic acid. Following gaseous treatment in I-plates, mycelial growth, sporulation, and spore germination of the isolates were inhibited at higher concentrations of thymol or acetic acid; however, acetic acid showed a little effect on the sporulation and spore germination of the isolates. Following the treatment of onion bulbs with 1000 mg L-1 of thymol 24 h before and after fungal inoculation, lesion diameter was greatly reduced compared with that following treatment with 0.5% ethanol (solvent control). Onion bulbs sprayed with thymol 24 h before fungal inoculation generally showed reduced lesion diameters by isolate F23 but not in isolate F15 compared with those sprayed 24 h after fungal inoculation. Collectively, thymol effectively inhibited the growth and development of A. awamori and B. aclada on amended media and in I-plates. In addition, spraying or fumigation of thymol is more desirable for effectively controlling these postharvest fungal pathogens during long-term storage conditions.

Colored LED Lights: Use One Color Alone or with Others for Growth in Hedyotis corymbosa In Vitro?

In recent years, light-emitting diode (LED) technology has been applied to improve crop production and induce targeted biochemical or physiological responses in plants. This study investigated the effect of different ratios of blue 450 nm and red 660 nm LEDs on the overall plant growth, photosynthetic characteristics, and total triterpenoid production in the leaves of Hedyotis corymbosa in vitro plants. The results showed that a high proportion of blue LED lights had a positive effect on enhancing photosynthesis and the overall biomass. In addition, blue LED lights were shown to be more effective in controlling the production of the total triterpenoid content compared with the red LED lights. Moreover, it was also found that plants grown under a high proportion of red LEDs exhibited reduced photosynthetic properties and even induced damage to the photosynthetic apparatus, which indicated that the blue or red LED lights played contrary roles in Hedyotis corymbosa.

What Traits Should Be Measured for Biomass in Kenaf?

Kenaf (Hibiscus cannabinus L.) is widely used as an important industrial crop. It has the potential to act as a sustainable energy provider in the future, and contains beneficial compounds for medical and therapeutic use. However, there are no clear breeding strategies to increase its biomass or leaf volume. Thus, to attain an increase in these parameters, we examined potential key traits such as stem diameter, plant height, and number of nodes to determine the relationship among them. We hypothesized that it would be easier to reduce the amount of time and labor required for breeding if correlations among these parameters are identified. In this study, we found a strong positive correlation between height and number of nodes (Spearman's Rho = 0.67, p < 0.001) and number of nodes and stem diameter (Spearman's Rho = 0.65, p < 0.001), but a relatively low correlation (Spearman's Rho = 0.34, p < 0.01) between height and stem diameter in the later stages of kenaf growth. We suggest that an efficient breeding strategy could be devised according to the breeding purpose, considering the correlations between various individual traits of kenaf.

Chlorine dioxide enhances lipid peroxidation through inhibiting calcium-independent cellular PLA2 in larvae of the Indianmeal moth, Plodia interpunctella.

Polyunsaturated fatty acids usually undergo lipid peroxidation induced by reactive oxygen species (ROS). Calcium-independent cellular phospholipase A2 (iPLA2) can maintain fatty acid compositions in phospholipids depending on physiological conditions. An insect iPLA2 (Pi-iPLA2) was predicted from the transciptome of the Indianmeal moth, Plodia interpunctella. It encodes 835 amino acids. It possesses five ankyrin repeats in the N terminal and patatin lipase domain in the C terminal. Pi-iPLA2 was expressed in all developmental stages of the Indianmeal moth. In the larval stage, it was expressed in all tissues tested. RNA interference (RNAi) specific to Pi-iPLA2 was performed using specific double-stranded RNA (dsRNA). It resulted in almost 70% of reduction in gene expression. Under such RNAi condition, P. interpunctella exhibited significant accumulation of lipid peroxidation based on the amount of malondialdehyde. RNAi of Pi-PLA2 expression also impaired cellular immune response of P. interpunctella. Chlorine dioxide (ClO2), an insecticidal agent by generating ROS, increased lipid peroxidation in a dose-dependent manner. However, the addition of vitamin E (an antioxidant) reduced the formation of lipid peroxidation. ClO2 treatment significantly reduced expression of Pi-iPLA2 but increased lipid peroxidation in larval fat body of P. interpunctella. Furthermore, larvae treated with dsRNA specific to Pi-iPLA2 were significantly susceptible to ClO2 treatment. These results suggest that Pi-iPLA2 plays a crucial role in repairing damaged fatty acids from phospholipids. Our results also suggest that ClO2 can elevate lipid peroxidation through inhibiting Pi-iPLA2 expression in addition to direct ROS production.

Priming-mediated systemic resistance in cucumber induced by Pseudomonas azotoformans GC-B19 and Paenibacillus elgii MM-B22 against Colletotrichum orbiculare.

Induced systemic resistance (ISR) can be activated by biotic agents, including root-associated beneficial bacteria to inhibit pathogen infection. We investigated priming-mediated ISR in cucumber induced by Pseudomonas azotoformans GC-B19 and Paenibacillus elgii MM-B22 against Colletotrichum orbiculare (causal fungus of anthracnose). In addition, we examined whether this ISR expression was bacterial density-dependent by assessing peroxidase activity in the presence and absence of the pathogen. As a result, root treatment with the ISR-eliciting strains GC-B19 and MM-B22 or the chemical inducer DL-ß-amino-n-butyric acid (positive control) significantly inhibited fungal infection process (conidial germination and appressorium formation) and disease severity compared with the non-ISR-eliciting strain, Pseudomonas aeruginosa PK-B09 (negative control), and MgSO4 solution (untreated control). These treatments effectively induced rapid elicitation of hypersensitive reaction-like cell death with H2O2 generations, and accumulation of defense-related enzymes (ß-1,3-glucanase, chitinase, and peroxidase) in cucumber leaves in the "primed" state against C. orbiculare. In addition, ISR expression was dependent on the bacterial cell density in the rhizosphere. This ISR expression was derived from the presence of sustained bacterial populations ranging from 10(4) to 10(6) cells/g of potting mix over a period of time after introduction of bacteria (10(6) to 10(10) cells/g of potting mix) into the rhizosphere. Taken together, these results suggest that priming-mediated ISR against C. orbiculare in cucumber can be induced in a bacterial density-dependent manner by Pseudomonas azotoformans GC-B19 and Paenibacillus elgii MM-B22.