Controlled Environment Facility Research Articles

Pre-Treatment with Bromelain Prevents Intestinal Dysbiosis in Pigs with Post-Weaning Diarrhea, without Increasing Antimicrobial Resistance in Escherichia coli.

Pigs are especially vulnerable to intestinal pathogens and dysbiosis in the first two weeks after weaning. Infection with enterotoxigenic strains of Escherichia coli (ETEC) in combination with poor nutrition and hygiene can lead to diarrhea, poor growth and increased mortality. While neomycin and zinc oxide can prevent post-weaning diarrhea (PWD), their broad-spectrum activity also kills commensal microbiota and can lead to the emergence of heavy metal and antimicrobial resistance. Bromelain prevents attachment of F4 ETEC to intestinal enterocytes by cleaving the host receptor. In controlled environmental facilities, weaned pigs treated with either therapeutic levels of neomycin sulfate, zinc oxide, bromelain or non-treated were monitored for diarrhea, weight gain, feed intake, feed efficiency, excretion of F4 ETEC, changes to their intestinal microbiomes and antimicrobial resistance in E. coli. The treatment effects were evaluated at weaning, during two weeks of treatment and for three weeks after treatments ceased. Minimal clinical signs of PWD were observed, except in zinc-treated pigs post treatment. Intestinal dysbiosis was observed in response to diarrhea and in pigs treated with both neomycin and zinc. Antimicrobial resistance increased in commensal E. coli isolated from neomycin- and zinc-treated pigs. In contrast, bromelain controlled PWD and prevented intestinal dysbiosis without inducing antimicrobial resistance.

First Report of Downy Mildew caused by Pseudoperonospora cannabina on Cannabis sativa in New York.

Hemp (Cannabis sativa <0.3% tetrahydrocannabinol) is an emerging crop used for grain, fiber, and cannabinoid production (Fike et al. 2020). In New York, hemp is grown both in controlled environment facilities, including greenhouses, and as a field crop. In August 2020, downy mildew-like symptoms were observed on leaves and inflorescence of hemp plants in a field research trial in Ithaca, NY. Several cultivars, including 'Auto CBD', were affected. Disease was severe with some plants reaching 75% disease severity at the individual plant level. In the most severely affected plots, there was no marketable yield. The disease was characterized by chlorotic and necrotic lesions producing sporangiophores under high humidity. Pigmented sporangia were produced on branched sporangiophores. On artificially inoculated leaves incubated at 18°C, 80% humidity, 12h light for 5d, sporangiophores produced 8-19 pigmented, lemon-shaped sporangia with mean ± SD dimensions of 25.2 ± 3.0 (18.9 to 30.4) x 18.2 ± 2.1 (14.6 to 23.2) µm (n=50). Each sporangium produced 2-5 zoospores after less than 45 min in water at room temperature (22°C). Sporangia were collected from sporulating lesions and DNA was extracted as outlined in Crowell et al. (2020). Fragments of the ribosomal internal transcribed spacer (ITS) region (White et al. 1990), the beta-tubulin ras-associated ypt1 gene (Moorman et al. 2002), and the mitochondrial cytochrome B oxidase subunit 2 (cox2) gene (Hudspeth et al. 2000) were amplified by PCR and sequenced bidirectionally. Sequences were deposited in GenBank under accession numbers OK086084, OM867581, and OM867580, respectively. BLAST searches using the amplified ITS and cox2 sequences resulted in 100% identity to Pseudoperonospora cannabina (HM636051.1, HM636003.1) with ypt1 aligning at 97.95% identity (382/390 bp) with P. cannabina (KJ651402.1). The molecular characterization identified the causal agent as P. cannabina. A representative isolate was deposited in the Cornell Plant Pathology Herbarium as CUP-070922. Sporangia were rinsed from detached leaves and used to confirm pathogenicity on whole plants. Ten 4-week-old 'Anka' plants were spray-inoculated until run off with a suspension of 1x104 sporangia mL-1. Ten control plants were sprayed with water. After inoculation, plants were placed in a 19˚C growth chamber with a 12-h photoperiod and misted for 30 min twice daily to maintain humidity above 80%. Sporangia and previously described symptoms were observed 7 days post-inoculation, while control plants were asymptomatic. The pathogen was reisolated onto detached leaves of 'Anka' from inoculated leaves where both sporangia and oospores were observed. The reisolated pathogen was confirmed morphologically and molecularly, through PCR amplification and bidirectional sequencing of the ITS, cox2, and ypt1 genes, as P. cannabina. To our knowledge, this is the first report of P. cannabina causing hemp downy mildew in New York. Depending on the severity and timing of infections, this disease could pose a significant threat to hemp production in the state. Other members of the genus, P. cubensis and P. humuli cause downy mildew on cucurbits and hops, respectively. As these can cause devastating diseases on their hosts, P. cannabina must be monitored with vigilance as an emerging pathogen (Purayannur et al. 2021; Savory et al. 2011). Literature Cited: Crowell, C. R., et al.2020. Plant Dis. 104:2949. DOI 10.1094/PDIS-04-20-0718-RE Fike, J. H., et al. 2020. Page 89 In: Sustainable Agriculture Reviews, vol 42. Springer, Cham, Switzerland. DOI 10.1007/978-3-030-41384-2_3 Hudspeth, D. S. S., et al. 2000. Mycologia 92:674. DOI 10.2307/3761425 Moorman, G. W., et al. 2002. Plant Dis. 86:1227. DOI 10.1094/PDIS.2002.86.11.1227 Purayannur, S., et al. 2021. Mol. Plant Pathol. 22:755. DOI 10.1111/mpp.13063 Savory, E. A., et al. 2011. Mol. Plant Pathol. 12:217. DOI 10.1111/j.1364-3703.2010.00670.x White, T. J., et al. 1990. Page 315 In: PCR Protocols. A Guide to Methods and Applications. Academic Press, San Diego, CA. DOI 10.1016/B978-0-12-372180-8.50042-1.

Effects of LED Red and Blue Spectra Irradiance Levels and Nutrient Solution EC on the Growth, Yield, and Phenolic Content of Lemon Basil (Ocimum citriodurum Vis.)

This research was conducted to study the effects of LED red and blue spectra irradiance levels and nutrient solution (electrical conductivity) and their interaction on the plant growth, yield, and phytochemical contents of lemon basil (Ocimum citriodorum Vis.) in a controlled environment. The controlled environment was equipped with red and blue spectra at a 4:1 ratio with irradiance levels of 80 and 160 µmol m−2 s−1 and irrigated with four different nutrient solution ECs at 1.0, 1.8, 2.6, and 3.4 mS cm−1, cultivated on a vertical structure. The temperature and relative humidity of the controlled environment and the pH of the nutrient solution were maintained at 26 and 18 °C day and night, 65 ± 5%, and pH 6, respectively. It was observed that plant height, canopy diameter, and the number of leaves of lemon basil had significantly increased under the irradiance levels of 160 µmol m−2 s−1 in combination with a nutrient solution EC of 2.6 mS cm−1. In addition, there was an interaction observed between the LED irradiance levels and the nutrient solution EC on the fresh weight of the stem and the dry weight of all the plant parts (leaves, stem, and roots). Lemon basil cultivated at 160 µmol m−2 s−1 and irrigated with 2.6 mS cm−1 was significantly higher in fresh stem weight and dry leaf, stem, and root weight at 17.36, 1.79, 1.82, and 0.22 g, respectively. The ascorbic acid of lemon basil was significantly higher under a treatment of 160 µmol m−2 s−1 irradiance level and an EC of 2.6 mS cm−1, and no interaction was observed. At the same time, there was an interaction observed between the LED irradiance level and the nutrient solution EC on the total phenolic content (TPC), total flavonoid content (TFC), and caftaric acid concentration of lemon basil. Lemon basil cultivated at 160 µmol m−2 s−1 and irrigated with 2.6 mS cm−1 was significantly higher in TPC, TFC, and caftaric acid concentration, with 1440.62 mg gallic acid equivalent to 100 g−1 DW, 1148.79 mg quercetin equivalent to 100 g−1 DW, and 2812.50 mg 100 g−1 DW, respectively. This result indicates that the irradiance levels of red and blue LED spectra at 160 µmol m−2 s−1 and irrigated with a nutrient solution EC of 2.6 mS cm−1 enhances the growth, yield production, and phenolic content of lemon basil in a controlled environment facility.

Scientific research trends for plant factory with artificial lighting: scoping review

Plant Factory With Artificial Lighting consists of a protected horticulture system in controlled environment facilities, in combination with various levels of growing surface and factors such as lighting, cultivation system, crop nutrition, and energy efficiency. The objective of this study was to identify in published scientific articles the current topics addressed, the potentialities and challenges identified, and their future position on the this system. This is a scoping review of 49 articles published in scientific journals that answered the research question “What are the topics addressed in the Journal Article on Plant Factory With Artificial Lighting?” from 2015 to 2022. The reviewed articles demonstrated that the development of alternatives for cultivation methods, lighting systems with variation of light spectrum, irrigation systems, and new technologies for the production chain, aimed at increasing production capacity, is a trend. They also indicated that, although the Plant Factory With Artificial Lightning has shown potential for the production of several crops, technical and economic optimization requires greater attention, pointing out that technological development and production methods are fundamental factors to establish the system as an alternative of agricultural production in sustainable urban centers.

Restoring a Threatened Ecological Community: Defining and Achieving Restoration Targets

Photo 1. The first aim was to define ecologically realistic and scale-appropriate restoration targets. (A) Here, Ben Miller, Lucy Commander, and Davide Abate are conducting vegetation surveys on the slopes of Koolanooka Range, which was found to have 120 species. (B) Western Australia's Threatened Ecological Community in the Koolanooka system occurs on a single rocky range of banded ironstone habitat (317-m elevation) in the Mid-west. (C) Lucy Commander, Luis Merino-Martín, and Davide Abate discuss the vegetation surveys that will identify the restoration target for the vegetation community. Photo credits: (A, B) Luis Merino-Martín, (C) Ben Miller. Photo 2. Partnerships with industry were essential to providing support for the research that informs the restoration of this Threatened Ecological Community on a mine waste rock landform. (A) Industry staff (Sinosteel Midwest Corporation) and research staff (Kings Park Science, Department of Biodiversity, Conservation and Attractions; The University of Western Australia) at Koolanooka discussing restoration activities. (B) Heavy machinery was needed to create restoration landforms with specific dimensions. (C) Research staff installing experimental plots (1 m2 or 5 m2) in the restoration trial area (0.86 ha) during final landform modifications (i.e., spreading of topsoil layer). Photo credits: Lucy Commander. Photo 3. The second aim was to identify an optimal approach to return species of this Threatened Ecological Community on the Koolanooka Range. (A) Planting of greenstock (10–13 species). (B) Trialed 25 species with direct sowing of seeds into topsoil that contained 32 species (inset: seed type diversity). (C) Completing the installation of the experimental restoration trial. Photo credits: Lucy Commander. Photo 4. The third aim was to optimize and facilitate the pathway for restoration. (A) Rainfall simulations were performed to measure water infiltration (i.e., the balance between precipitation and runoff) to identify the soil water availability for plant establishment in different soil covers. (B) The controlled environment facility on site that was used to understand the impact of reduced rainfall and its interaction with different soil covers on plant establishment. (C) Sowing seeds in experimental plots to test the interactions between seed functional traits and soil preparation. Photo credits: Luis Merino-Martín. Photo 5. The fourth aim was to develop a protocol to assess restoration achievements. (A) Peter Golos, Davide Abate, and Luis Merino-Martín monitor the experimental plots (1 m2 or 5 m2) to determine seedling emergence and survival. (B) Vegetation coverage of the experimental restoration trial on the slopes of the waste rock landform, 20 months after installation. (C) Diverse composition of species established in the experimental restoration trial on the top of the waste rock landform. Photo credits: (A) Barney Wilczak; (B) Carole Elliott; (C) Arielle Fontaine. These photographs illustrate the article “An approach to defining and achieving restoration targets for a threatened plant community” by C. P. Elliott, L. E. Commander, L. Merino-Martín, P. J. Golos, J. Stevens, and B. P. Miller published in Ecological Applications. https://doi.org/10.1002/eap.2613

Empirical Evaluation of Inflorescences' Morphological Attributes for Yield Optimization of Medicinal Cannabis Cultivars.

In recent decades with the reacknowledgment of the medicinal properties of Cannabis sativa L. (cannabis) plants, there is an increased demand for high performing cultivars that can deliver quality products for various applications. However, scientific knowledge that can facilitate the generation of advanced cannabis cultivars is scarce. In order to improve cannabis breeding and optimize cultivation techniques, the current study aimed to examine the morphological attributes of cannabis inflorescences using novel image analysis practices. The investigated plant population comprises 478 plants ascribed to 119 genotypes of high−THC or blended THC−CBD ratio that was cultivated under a controlled environment facility. Following harvest, all plants were manually processed and an image of the trimmed and refined inflorescences extracted from each plant was captured. Image analysis was then performed using in-house custom-made software which extracted 8 morphological features (such as size, shape and perimeter) for each of the 127,000 extracted inflorescences. Our findings suggest that environmental factors play an important role in the determination of inflorescences’ morphology. Therefore, further studies that focus on genotype X environment interactions are required in order to generate inflorescences with desired characteristics. An examination of the intra-plant inflorescences weight distribution revealed that processing 75% of the plant’s largest inflorescences will gain 90% of its overall yield weight. Therefore, for the optimization of post-harvest tasks, it is suggested to evaluate if the benefits from extracting and processing the plant’s smaller inflorescences outweigh its operational costs. To advance selection efficacy for breeding purposes, a prediction equation for forecasting the plant’s production biomass through width measurements of specific inflorescences, formed under the current experimental methodology, was generated. Thus, it is anticipated that findings from the current study will contribute to the field of medicinal cannabis by improving targeted breeding programs, advancing crop productivity and enhancing the efficacy of post-harvest procedures.

Regionalized dynamic climate series for ecological climate impact research in modern controlled environment facilities.

Modern controlled environment facilities (CEFs) enable the simulation of dynamic microclimates in controlled ecological experiments through their technical ability to precisely control multiple environmental parameters. However, few CEF studies exploit the technical possibilities of their facilities, as climate change treatments are frequently applied by static manipulation of an inadequate number of climate change drivers, ignoring intra‐annual variability and covariation of multiple meteorological variables. We present a method for generating regionalized climate series in high temporal resolution that was developed to force the TUMmesa Model EcoSystem Analyzer with dynamic climate simulations. The climate series represent annual cycles for a reference period (1987–2016) and the climate change scenarios RCP2.6 and RCP8.5 (2071–2100) regionalized for a climate station situated in a forested region of the German Spessart mountains. Based on the EURO‐CORDEX and ReKliEs‐DE model ensembles, typical annual courses of daily resolved climatologies for the reference period and the RCP scenarios were calculated from multimodel means of temperature (ta), relative humidity (rh), global radiation (Rg), air pressure (P), and ground‐level ozone and complemented by CO2. To account for intra‐annual variation and the covariability of multiple climate variables, daily values were substituted by hourly resolved data resampled from the historical record. The resulting present climate Test Reference Year (TRY) well represented a possible annual cycle within the reference period, and expected shifts in future mean values (e.g., higher ta) were reproduced within the RCP TRYs. The TRYs were executed in eight climate chambers of the TUMmesa facility and—accounting for the technical boundaries of the facility—reproduced with high precision. Especially, as an alternative to CEF simulations that reproduce mere day/night cycles and static manipulations of climate change drivers, the method presented here proved well suited for simulating regionalized and highly dynamic annual cycles for ecological CEF studies.

The characterization of key physiological traits of medicinal cannabis (Cannabis sativa L.) as a tool for precision breeding

BackgroundFor millennia, drug-type cannabis strains were extensively used for various medicinal, ritual, and inebriant applications. However, cannabis prohibition during the last century led to cultivation and breeding activities being conducted under clandestine conditions, while scientific development of the crop ceased. Recently, the potential of medicinal cannabis has been reacknowledged and the now expanding industry requires optimal and scientifically characterized varieties. However, scientific knowledge that can propel this advancement is sorely lacking. To address this issue, the current study aims to provide a better understanding of key physiological and phenological traits that can facilitate the breeding of advanced cultivars.ResultsA diverse population of 121 genotypes of high-THC or balanced THC-CBD ratio was cultivated under a controlled environment facility and 13 plant parameters were measured. No physiological association across genotypes attributed to the same vernacular classification was observed. Floral bud dry weight was found to be positively associated with plant height and stem diameter but not with days to maturation. Furthermore, the heritability of both plant height and days to maturation was relatively high, but for plant height it decreased during the vegetative growth phase. To advance breeding efficacy, a prediction equation for forecasting floral bud dry weight was generated, driven by parameters that can be detected during the vegetative growth phase solely.ConclusionsOur findings suggest that selection for taller and fast-growing genotypes is likely to lead to an increase in floral bud productivity. It was also found that the final plant height and stem diameter are determined by 5 independent factors that can be used to maximize productivity through cultivation adjustments. The proposed prediction equation can facilitate the selection of prolific genotypes without the completion of a full cultivation cycle. Future studies that will associate genome-wide variation with plants morphological traits and cannabinoid profile will enable precise and accelerated breeding through genomic selection approaches.

Ecotrons: Powerful and versatile ecosystem analysers for ecology, agronomy and environmental science.

Ecosystems integrity and services are threatened by anthropogenic global changes. Mitigating and adapting to these changes require knowledge of ecosystem functioning in the expected novel environments, informed in large part through experimentation and modelling. This paper describes 13 advanced controlled environment facilities for experimental ecosystem studies, herein termed ecotrons, open to the international community. Ecotrons enable simulation of a wide range of natural environmental conditions in replicated and independent experimental units while measuring various ecosystem processes. This capacity to realistically control ecosystem environments is used to emulate a variety of climatic scenarios and soil conditions, in natural sunlight or through broad‐spectrum lighting. The use of large ecosystem samples, intact or reconstructed, minimizes border effects and increases biological and physical complexity. Measurements of concentrations of greenhouse trace gases as well as their net exchange between the ecosystem and the atmosphere are performed in most ecotrons, often quasi continuously. The flow of matter is often tracked with the use of stable isotope tracers of carbon and other elements. Equipment is available for measurements of soil water status as well as root and canopy growth. The experiments ran so far emphasize the diversity of the hosted research. Half of them concern global changes, often with a manipulation of more than one driver. About a quarter deal with the impact of biodiversity loss on ecosystem functioning and one quarter with ecosystem or plant physiology. We discuss how the methodology for environmental simulation and process measurements, especially in soil, can be improved and stress the need to establish stronger links with modelling in future projects. These developments will enable further improvements in mechanistic understanding and predictive capacity of ecotron research which will play, in complementarity with field experimentation and monitoring, a crucial role in exploring the ecosystem consequences of environmental changes.

High-Throughput Corn Image Segmentation and Trait Extraction Using Chlorophyll Fluorescence Images.

Plant segmentation and trait extraction for individual organs are two of the key challenges in high-throughput phenotyping (HTP) operations. To address this challenge, the Ag Alumni Seed Phenotyping Facility (AAPF) at Purdue University utilizes chlorophyll fluorescence images (CFIs) to enable consistent and efficient automatic segmentation of plants of different species, age, or color. A series of image analysis routines were also developed to facilitate the quantitative measurements of key corn plant traits. A proof-of-concept experiment was conducted to demonstrate the utility of the extracted traits in assessing drought stress reaction of corn plants. The image analysis routines successfully measured several corn morphological characteristics for different sizes such as plant height, area, top-node height and diameter, number of leaves, leaf area, and angle in relation to the stem. Data from the proof-of-concept experiment showed how corn plants behaved when treated with different water regiments or grown in pot of different sizes. High-throughput image segmentation and analysis basing on a plant's fluorescence image was proved to be efficient and reliable. Extracted trait on the segmented stem and leaves of a corn plant demonstrated the importance and utility of this kind of trait data in evaluating the performance of corn plant under stress. Data collected from corn plants grown in pots of different volumes showed the importance of using pot of standard size when conducting and reporting plant phenotyping data in a controlled-environment facility.

Improved cyber-physical system captured post-flowering high night temperature impact on yield and quality of field grown wheat

Winter wheat (Triticum aestivum L.) is essential to maintain food security for a large proportion of the world’s population. With increased risk from abiotic stresses due to climate variability, it is imperative to understand and minimize the negative impact of these stressors, including high night temperature (HNT). Both globally and at regional scales, a differential rate of increase in day and night temperature is observed, wherein night temperatures are increasing at a higher pace and the trend is projected to continue into the future. Previous studies using controlled environment facilities and small field-based removable chambers have shown that post-anthesis HNT stress can induce a significant reduction in wheat grain yield. A prototype was previously developed by utilizing field-based tents allowing for simultaneous phenotyping of popular winter wheat varieties from US Midwest and advanced breeding lines. Hence, the objectives of the study were to (i) design and build a new field-based infrastructure and test and validate the uniformity of HNT stress application on a scaled-up version of the prototype (ii) improve and develop a more sophisticated cyber-physical system to sense and impose post-anthesis HNT stress uniformly through physiological maturity within the scaled-up tents; and (iii) determine the impact of HNT stress during grain filling on the agronomic and grain quality parameters including starch and protein concentration. The system imposed a consistent post-anthesis HNT stress of + 3.8 °C until maturity and maintained uniform distribution of stress which was confirmed by (i) 0.23 °C temperature differential between an array of sensors within the tents and (ii) statistically similar performance of a common check replicated multiple times in each tent. On average, a reduction in grain-filling duration by 3.33 days, kernel weight by 1.25% per °C, grain number by 2.36% per °C and yield by 3.58% per °C increase in night temperature was documented. HNT stress induced a significant reduction in starch concentration indicating disturbed carbon balance. The pilot field-based facility integrated with a robust cyber-physical system provides a timely breakthrough for evaluating HNT stress impact on large diversity panels to enhance HNT stress tolerance across field crops. The flexibility of the cyber-physical system and movement capabilities of the field-based infrastructure allows this methodology to be adaptable to different crops.

Translocation and persistence of soil applied chlorantraniliprole as a control measure for Chloridea virescens in tobacco plant Nicotiana tabacum

Chloridea(Heliothis) virescens (F.) (Lepidoptera: Noctuidae) (tobacco budworm) management in pre-topped tobacco remains a concern for growers. Chlorantraniliprole, an anthranilic diamide insecticide, emerged as an option for C. virescens in early season tobacco because it selectively targets caterpillars, exhibits systemic action, and satisfies reduced risk classification. It is currently recommended for foliar application at threshold; however, because of its systemic action, many growers deploy soil applications at transplant. We conducted a series of experiments to determine the potential efficacy and longevity of soil applications of chlorantraniliprole for use against C. virescens in tobacco. First, tobacco plants were grown in the NCSU Phytotron, a controlled environment facility, and were treated with chlorantraniliprole soil applications either as a soil injection or soil drench at field equivalent rates at transplant. Plants were either watered daily or two times per week. A field experiment was established at two locations where at transplant in furrow and soil drench applications of chlorantraniliprole were compared to foliar applications. In both these experiments, one of the youngest leaves of adequate length on a subset of plants was sampled weeks three through nine after transplant in the phytotron and five through eight after transplant at the field stations. One-half of each leaf was exposed to second instar C. virescens to assess mortality and feeding, and the other half was analyzed for chlorantraniliprole concentration. Mortality differed between treatments in phytotron and field trials after 96 h exposure. Frass production and survivorship increased as plants grew. Phytotron trials demonstrated longer toxicity to C. virescens than field experiments, and chlorantraniliprole concentrations decreased at a slower rate in the Phytotron than in the field. Our field results suggest that soil applications of chlorantraniliprole are not likely to provide acceptable early season C. virescens control in the field.

Design and implementation of a low-cost sensor network to monitor environmental and agronomic variables in a plant factory

Monitoring equipment for plant-factory automation requires big capital investments. Low-cost open-source microcontroller platforms have been employed in agriculture to monitor and control different variables of importance for crop production. A low-cost plant-factory monitoring system for measuring air temperature, relative humidity, plant-leaf temperature, pH, electrical conductivity, dissolved oxygen and temperature of the nutrient solution is presented here. All the information is recorded in a micro SD memory and can be accessed by Bluetooth in real-time. The developed system was tested during a cycle of a lettuce crop in a research plant-factory facility. The quality of the collected data was evaluated and compared with a well-known research-grade monitoring system. The low-cost sensors showed an easy to correct bias when were compared to those of research-grade, with a correlation coefficient over 0.96. The results showed that low-cost systems, like the one implemented here, are a good alternative for monitoring environmental and physiological variables in controlled environmental agriculture facilities.

Narrowing Diurnal Temperature Amplitude Alters Carbon Tradeoff and Reduces Growth in C4 Crop Sorghum.

Effect of diurnal temperature amplitude on carbon tradeoff (photosynthesis vs. respiration) and growth are not well documented in C4 crops, especially under changing temperatures of light (daytime) and dark (nighttime) phases in 24 h of a day. Fluctuations in daytime and nighttime temperatures due to climate change narrows diurnal temperature amplitude which can alter circadian rhythms in plant, thus influence the ability of plants to cope with temperature changes and cause contradictory responses in carbon tradeoff, particularly in night respiration during dark phase, and growth. Sorghum [Sorghum bicolor (L.) Moench] is a key C4 cereal crop grown in high temperature challenging agro-climatic regions. Hence, it is important to understand its response to diurnal temperature amplitude. This is the first systematic investigation using controlled environmental facility to monitor the response of sorghum to different diurnal temperature amplitudes with same mean temperature. Two sorghum hybrids (DK 53 and DK 28E) were grown under optimum (27°C) and high (35°C) mean temperatures with three different diurnal temperature amplitudes (2, 10, and 18°C) accomplished by modulating daytime and nighttime temperatures [optimum daytime and nighttime temperatures (ODNT): 28/26, 32/22, and 36/18°C and high daytime and nighttime temperatures (HDNT): 36/34, 40/30, and 44/26°C]. After exposure to different temperature conditions, total soluble sugars, starch, total leaf area and biomass were reduced, while night respiration and specific leaf area were increased with narrowing of diurnal temperature amplitude (18 to 2°C) of HDNT followed by ODNT. However, there was no influence on photosynthesis across different ODNT and HDNT. Contradiction in response of foliar gas exchange and growth suggests higher contribution of night respiration for maintenance rather than growth with narrowing of diurnal temperature amplitude of ODNT and HDNT. Results imply that diurnal temperature amplitude has immense impact on the carbon tradeoff and growth, regardless of hybrid variation. Hence, diurnal temperature amplitude and night respiration should be considered while quantifying response and screening for high temperature tolerance in sorghum genotypes and comprehensive understanding of dark phase mechanisms which are coupled with stress response can further strengthen screening procedures.

The additive effect of a stem galling moth and a competitive plant on parthenium weed under CO2 enrichment

Parthenium weed (Parthenium hysterophorus) is a highly invasive plant that has invaded many parts of world including Australia. The present study reports on the effects of rising [CO2] on the performance of one of its biological control agents, stem-galling moth (Epiblema strenuana) when combined with a competitive plant, buffel grass (Cenchrus cilliaris). The study was carried out under controlled environment facilities during 2010–11. P. hysterophorus when grown under elevated [CO2] of 550 µmol mol−1, produced a greater biomass (27%), attained greater stature (31%), produced more branches (45%) and seeds plant−1 (20%), than those grown at ambient [CO2] of 380 µmol mol−1. Buffel grass reduced the biomass and seed production of P. hysterophorus plants by 33% and 22% under ambient [CO2] and by 19% and 17% under elevated [CO2], respectively. The combined effect of buffel grass and E. strenuana reduced dry biomass and seed production by 42% and 72% under ambient [CO2] and 29% and 37% elevated [CO2], respectively. Although the suppressive effect was different between ambient and elevated [CO2], the effect is likely to be retained. Stem gall formation by E. strenuana significantly enhanced the lateral branch production in plants grown under both [CO2]. Epiblema strenuana did not reduce the seed production of P. hysterophorus under the elevated [CO2] nevertheless, our earlier study had confirmed that many of the seeds produced under such conditions are not filled. This study has highlighted that the additive suppressive effect of E. strenuana and buffel grass on P. hysterophorus growth would be retained under future atmospheric CO2 enrichment.

Affordable remote monitoring of plant growth in facilities using Raspberry Pi computers.

PremiseEnvironmentally controlled facilities, such as growth chambers, are essential tools for experimental research. Automated, low‐cost, remote‐monitoring hardware can greatly improve both reproducibility and maintenance.Methods and ResultsUsing a Raspberry Pi computer, open‐source software, environmental sensors, and a camera, we developed Growth Monitor pi (GMpi), a cost‐effective system for monitoring growth chamber conditions. Coupled with our software, GMPi_Pack, our setup automates sensor readings, photography, and alerts when conditions fall out of range.Conclusions GMpi offers access to environmental data logging, improving reproducibility of experiments and reinforcing the stability of controlled environmental facilities. The device is also flexible and scalable, allowing researchers the ability to customize and expand GMpi for their own needs.

Agriculture 2.0: Light Emitting Diode (LED), Light Quality, and Crop Production in Controlled Environment Facilities

Agriculture 2.0: Light Emitting Diode (LED), Light Quality, and Crop Production in Controlled Environment Facilities

Estimation of particulate matter and gaseous concentrations using low-cost sensors from broiler houses.

Particulate and gaseous emissions from intensive poultry facilities are major public and environmental health concern. The present study was aimed at exploratively monitoring particulate matter (PM) and gaseous concentrations in controlled-environment facilities using low-cost sensors in Lahore, Pakistan. The indoors and outdoors of 18 broiler houses, grouped into three categories based on the age of birds: group I (1-20days), group II (21-30days) and group III (31-40days), were examined. Low-cost sensors Dylos 1700 and Aeroqual 500 series with different gas sensor heads were used to monitor PM and different gases such as nitrogen dioxide (NO2), hydrogen sulphide (H2S), carbon dioxide (CO2) and methane (CH4), respectively. Overall, the mean PM and gaseous concentrations increased with the age and activity of birds as compared with the non-activity time of birds. Statistically significant differences were observed in all measured parameters among the groups. The negative correlation between indoor and outdoor environments for PM and gas concentrations at some broiler houses demonstrates the contribution of additional sources to emissions in outdoor environments. The findings contribute to our knowledge of temporal characteristics of particulate and gaseous concentrations from poultry facilities particularly in Pakistan and generally to the capability of using low-cost sensors to evaluate emissions from such facilities.

Quantitative Trait Loci for Freezing Tolerance in a Lowland x Upland Switchgrass Population.

Low-temperature related abiotic stress is an important factor affecting winter survival in lowland switchgrass when grown in northern latitudes in the United States. A better understanding of the genetic architecture of freezing tolerance in switchgrass will aid the development of lowland switchgrass cultivars with improved winter survival. The objectives of this study were to conduct a freezing tolerance assessment, generate a genetic map using single nucleotide polymorphism (SNP) markers, and identify QTL (quantitative trait loci) associated with freezing tolerance in a lowland × upland switchgrass population. A pseudo-F2 mapping population was generated from an initial cross between the lowland population Ellsworth and the upland cultivar Summer. The segregating progenies were screened for freezing tolerance in a controlled-environment facility. Two clonal replicates of each genotype were tested at six different treatment temperatures ranging from −15 to −5°C at an interval of 2°C for two time periods. Tiller emergence (days) and tiller number were recorded following the recovery of each genotype with the hypothesis that upland genotype is the source for higher tiller number and early tiller emergence. Survivorship of the pseudo-F2 population ranged from 89% at −5°C to 5% at −15°C with an average LT50 of −9.7°C. Genotype had a significant effect on all traits except tiller number at −15°C. A linkage map was constructed from bi-allelic single nucleotide polymorphism markers generated using exome capture sequencing. The final map consisted of 1618 markers and 2626 cM, with an average inter-marker distance of 1.8 cM. Six significant QTL were identified, one each on chromosomes 1K, 5K, 5N, 6K, 6N, and 9K, for the following traits: tiller number, tiller emergence days and LT50. A comparative genomics study revealed important freezing tolerance genes/proteins, such as COR47, DREB2B, zinc finger-CCCH, WRKY, GIGANTEA, HSP70, and NRT2, among others that reside within the 1.5 LOD confidence interval of the identified QTL.

Evaluation of Bradyrhizobium formulations on performance of soybean grown on soil without a long-term history of the crop

Farmers have raised concerns about the inability of some commercial soybean inoculants to elicit effective nodulation. Nodulation failure has been attributed to, among others, high temperatures, soil acidity and type of inoculant used. This work examined the influence of two Bradyrhizobium japonicum inoculant formulations on soybean grown on soil without a soybean cropping history for about eight years. The experiment was conducted in a controlled environment facility at the University of KwaZulu-Natal. The treatments were two levels of a liquid formulation of the Bradyrhizobium WB 74 initially consisting of 2.6×109 colony forming units ml-1 and one level of a powder formulation containing a minimum of 6.5×108 live cells g-1. The results showed that applying the two formulations of B. japonicum to seed, enhanced soybean nodule number, leaf number, nutrient concentration and uptake compared to the control treatment, and both powder and liquid formulations enhanced yield components to the same extent. Although the low concentration of the liquid formulation was less effective in increasing nodule number, other responses it elicited were comparable to the high concentration of the liquid and powder formulations. We conclude that small differences may exist between commonly available commercial inoculants of Bradyrhizobium WB 74 but they are effective in promoting nodulation and growth of soybean, and that reported major nodulation failures may be attributed to management factors other than inoculant formulation per se.