Horticultural Crops Research Articles

The Roles of Plant-Growth-Promoting Rhizobacteria (PGPR)-Based Biostimulants for Agricultural Production Systems.

The application of biostimulants has been proven to be an advantageous tool and an appropriate form of management towards the effective use of natural resources, food security, and the beneficial effects on plant growth and yield. Plant-growth-promoting rhizobacteria (PGPR) are microbes connected with plant roots that can increase plant growth by different methods such as producing plant hormones and molecules to improve plant growth or providing increased mineral nutrition. They can colonize all ecological niches of roots to all stages of crop development, and they can affect plant growth and development directly by modulating plant hormone levels and enhancing nutrient acquisition such as of potassium, phosphorus, nitrogen, and essential minerals, or indirectly via reducing the inhibitory impacts of different pathogens in the forms of biocontrol parameters. Many plant-associated species such as Pseudomonas, Acinetobacter, Streptomyces, Serratia, Arthrobacter, and Rhodococcus can increase plant growth by improving plant disease resistance, synthesizing growth-stimulating plant hormones, and suppressing pathogenic microorganisms. The application of biostimulants is both an environmentally friendly practice and a promising method that can enhance the sustainability of horticultural and agricultural production systems as well as promote the quantity and quality of foods. They can also reduce the global dependence on hazardous agricultural chemicals. Science Direct, Google Scholar, Springer Link, CAB Direct, Scopus, Springer Link, Taylor and Francis, Web of Science, and Wiley Online Library were checked, and the search was conducted on all manuscript sections in accordance with the terms Acinetobacter, Arthrobacter, Enterobacter, Ochrobactrum, Pseudomonas, Rhodococcus, Serratia, Streptomyces, Biostimulants, Plant growth promoting rhizobactera, and Stenotrophomonas. The aim of this manuscript is to survey the effects of plant-growth-promoting rhizobacteria by presenting case studies and successful paradigms in various agricultural and horticultural crops.

Mechanism underlying the rapid growth of Phalaenopsis equestris induced by 60Co-γ-ray irradiation.

Gamma (γ)-ray irradiation is one of the important modern breeding methods. Gamma-ray irradiation can affect the growth rate and other characteristics of plants. Plant growth rate is crucial for plants. In horticultural crops, the growth rate of plants is closely related to the growth of leaves and flowering time, both of which have important ornamental value. In this study, 60Co-γ-ray was used to treat P. equestris plants. After irradiation, the plant's leaf growth rate increased, and sugar content and antioxidant enzyme activity increased. Therefore, we used RNA-seq technology to analyze the differential gene expression and pathways of control leaves and irradiated leaves. Through transcriptome analysis, we investigated the reasons for the rapid growth of P. equestris leaves after irradiation. In the analysis, genes related to cell wall relaxation and glucose metabolism showed differential expression. In addition, the expression level of genes encoding ROS scavenging enzyme synthesis regulatory genes increased after irradiation. We identified two genes related to P. equestris leaf growth using VIGS technology: PeNGA and PeEXPA10. The expression of PeEXPA10, a gene related to cell wall expansion, was down-regulated, cell wall expansion ability decreased, cell size decreased, and leaf growth rate slowed down. The TCP-NGATHA (NGA) molecular regulatory module plays a crucial role in cell proliferation. When the expression of the PeNGA gene decreases, the leaf growth rate increases, and the number of cells increases. After irradiation, PeNGA and PeEXPA10 affect the growth of P. equestris leaves by influencing cell proliferation and cell expansion, respectively. In addition, many genes in the plant hormone signaling pathway show differential expression after irradiation, indicating the crucial role of plant hormones in plant leaf growth. This provides a theoretical basis for future research on leaf development and biological breeding.

Postharvest Losses and Management of Horticultural Produce: A Review

Horticultural postharvest losses pose a significant challenge to the supply chain and economic growth, particularly in impoverished nations. This review paper explores the multifaceted issues surrounding postharvest losses in horticultural crops and emphasizes the critical role of technological innovations in mitigating these losses. Various stakeholders within the value chain, including farmers, handlers, and consumers, face substantial risks due to insufficient postharvest handling techniques. The study underscores the urgency of adopting advanced postharvest technologies, focusing on enhanced harvesting and packaging strategies. By using cutting-edge technologies, it is possible to lower losses after harvest and raise the general standard of fresh produce. The improper use of packing materials and inadequate packaging methods significantly contribute to these losses, making it imperative to address these aspects for sustainable solutions. This comprehensive review not only identifies the reason for fruit and vegetable losses after harvesting within the countries but also provides actionable insights into mitigating measures. This article intends to support the creation of a robust and successful horticulture supply chain by addressing the issues and offering workable solutions. The integration of technological advancements in harvesting, handling, and packaging processes emerges as a key element in the overall strategy to reduce postharvest losses and promote economic growth in resource-constrained regions.

A Review on Organic Manure and Plant Growth Promoting Rhizobacteria’s Use in Horticultural Crops

The sustainable and eco-friendly management of horticulture crops has become increasingly imperative in contemporary agricultural practices. This review summarizes the current knowledge on the synergistic utilization of organic manure and plant growth-promoting rhizobacteria (PGPR) to enhance the growth, yield, and overall health of horticulture crops. Organic manures, derived from natural sources such as compost, animal manure, and green manure, offer a sustainable alternative to synthetic fertilizers, providing essential nutrients while promoting soil fertility and structure. PGPR can affect on plant growth by production and releases secondary metabolites, helps in preventing deleterious effects of phyto-pathogenic organisms in the rhizosphere. This will ultimately support for better yield and quality of horticultural crops.

Determinant Factors of the Quality of Work of Life of Employees at the Horticulture and Plantation Food Crops Service of Merauke Regency

The performance assessment of the Merauke Regency Horticulture and Plantation Food Crops Service according to the government agency performance accountability system (SAKIP) in 2021 is still low, namely 69.87. Efforts need to be made to improve performance. This research highlights the quality of employees in dividing their time between work in the office and personal life. Improving the quality of employee work and life or Quality Work and Live (QWL) according to the initial survey is known to be possible by improving career development variables, work-life balance, employee attitudes, and compensation. This research aims to determine the determinant factors of QWL of employees at the Merauke Regency Horticulture and Plantation Food Crops Service. The research uses a descriptive quantitative method of hypothesis testing research over explanatory research because it is intended to explain the relationship of influence between variables through hypotheses. The research results show that work live balance (WLB) has a positive and insignificant effect on QWL, where increasing WLB can increase QWL. The more balanced work and life are, the higher the quality of work and life. Career development has a positive and insignificant effect on QWL. Smooth and fair career development will increase QWL. Meanwhile, office management's focus must be on variables with positive and significant results, where attitude has a positive and significant effect on QWL and compensation has a positive and significant effect on QWL. So efforts are needed to increase obedience and loyalty as part of the employee's attitude to the service as well as providing fair and transparent compensation.

A Concept of Hydroponic System in Horticultural Crops

In now a day’s soil based cultivation is major difficulties due to different man made reason such as urbanization and industrialization. Hydroponic system such as the deep flow technique, nutrient film technique and aeroponic systems are essential tools in plant factories more over sudden natural disaster, climate change and unlimited use of chemical for agriculture purpose lead to reduction in soil fertility and quality. That’s why scientist have evolved a new alternative approach to the agriculture system is called as hydroponic system. Hydroponic is a technique of growing plants in a water based and nutrient rich solution by hydroponic large number of crops for plants can be grown easily. The quality of yield and nutritive value of end products produced by hydroponically is generally greater than the natural soil based cultivation. This type of cultivation is diseases free, eco-friendly and growing popularity across the whole world including the both developed and developing countries.

AgAID Institute—AI for agricultural labor and decision support

AbstractThe AgAID Institute is a National AI Research Institute focused on developing AI solutions for specialty crop agriculture. Specialty crops include a variety of fruits and vegetables, nut trees, grapes, berries, and different types of horticultural crops. In the United States, the specialty crop industry accounts for a multibillion dollar industry with over 300 crops grown just along the U.S. west coast. Specialty crop agriculture presents several unique challenges: they are labor‐intensive, are easily impacted by weather extremities, and are grown mostly on irrigated lands and hence are dependent on water. The AgAID Institute aims to develop AI solutions to address these challenges, particularly in the face of workforce shortages, water scarcity, and extreme weather events. Addressing this host of challenges requires advancing foundational AI research, including spatio‐temporal system modeling, robot sensing and control, multiscale site‐specific decision support, and designing effective human–AI workflows. This article provides examples of current AgAID efforts and points to open directions to be explored.

Mitigation of salt stress in lettuce by a biostimulant that protects the root absorption zone and improves biochemical responses.

Horticultural crops constantly face abiotic stress factors such as salinity, which have intensified in recent years due to accelerated climate change, significantly affecting their yields and profitability. Under these conditions, it has become necessary to implement effective and sustainable solutions to guarantee agricultural productivity and food security. The influence of BALOX®, a biostimulant of plant origin, was tested on the responses to salinity of Lactuca sativa L. var. longifolia plants exposed to salt concentrations up to 150 mM NaCl, evaluating different biometric and biochemical properties after 25 days of treatment. Control plants were cultivated under the same conditions but without the biostimulant treatment. An in situ analysis of root characteristics using a non-destructive, real-time method was also performed. The salt stress treatments inhibited plant growth, reduced chlorophyll and carotenoid contents, and increased the concentrations of Na+ and Cl- in roots and leaves while reducing those of Ca2+. BALOX® application had a positive effect because it stimulated plant growth and the level of Ca2+ and photosynthetic pigments. In addition, it reduced the content of Na+ and Cl- in the presence and the absence of salt. The biostimulant also reduced the salt-induced accumulation of stress biomarkers, such as proline, malondialdehyde (MDA), and hydrogen peroxide (H2O2). Therefore, BALOX® appears to significantly reduce osmotic, ionic and oxidative stress levels in salt-treated plants. Furthermore, the analysis of the salt treatments' and the biostimulant's direct effects on roots indicated that BALOX®'s primary mechanism of action probably involves improving plant nutrition, even under severe salt stress conditions, by protecting and stimulating the root absorption zone.

Transcriptional regulation of flavonol biosynthesis in plants.

Flavonols are a class of flavonoids that play a crucial role in regulating plant growth and promoting stress resistance. They are also important dietary components in horticultural crops due to their benefits for human health. In past decades, research on the transcriptional regulation of flavonol biosynthesis in plants has increased rapidly. This review summarizes recent progress in flavonol-specific transcriptional regulation in plants, encompassing characterization of different categories of transcription factors (TFs) and microRNAs as well as elucidation of different transcriptional mechanisms, including direct and cascade transcriptional regulation. Direct transcriptional regulation involves TFs, such as MYB, AP2/ERF, and WRKY, which can directly target the key flavonol synthase gene or other early genes in flavonoid biosynthesis. In addition, different regulation modules in cascade transcriptional regulation involve microRNAs targeting TFs, regulation between activators, interaction between activators and repressors, and degradation of activators or repressors induced by UV-B light or plant hormones. Such sophisticated regulation of the flavonol biosynthetic pathway in response to UV-B radiation or hormones may allow plants to fine-tune flavonol homeostasis, thereby balancing plant growth and stress responses in a timely manner. Based on orchestrated regulation, molecular design strategies will be applied to breed horticultural crops with excellent health-promoting effects and high resistance.

Comparative transcriptome analysis revealed gene expression differences in fruits between two Actinidia chinensis cultivars

The kiwifruit JD (Jindun No. 1) and HY (Hongyang) are two species of Actinidia chinensis, a major horticultural crop growing worldwide. Fruity texture and taste of HY are better compared with that of JD. However, the fruit transcriptome differences at the ripening stage between JD and HY are poorly understood. In this study, we identified a total of 2,565 differentially expressed genes (DEGs), including 1,336 upregulated and 1,229 downregulated DEGs between the two cultivars. Among the total DEGs, 2,329 matched at least one database. Meanwhile, 1,915 could be aligned to the GO (Gene Ontology), 551 could be aligned to the KEGG (Kyoto Encyclopedia of Genes and Genomes Pathway), and 2,187 could be aligned to SWISS-PROT (SWISS-PROT Protein Sequence) database, respectively. To analyze the DEGs using functional categorization, some regulated processes were significantly changed, and 52 TF (transcription factor) families were detected. This study revealed the change in gene expression level at maturity through the analysis of DEGs data, and these data can provide valuable clues for exploring the molecular mechanism between two kiwifruit varieties, and will be helpful for molecular breeding in Actinidia plants.

Transcriptome Analysis Reveals the Mechanism by Which Exogenous Melatonin Treatment Delays Leaf Senescence of Postharvest Chinese Kale (Brassica oleracea var. alboglabra).

Melatonin, a pleiotropic small molecule, is employed in horticultural crops to delay senescence and preserve postharvest quality. In this study, 100 µM melatonin treatment delayed a decline in the color difference index h* and a*, maintaining the content of chlorophyll and carotenoids, thereby delaying the yellowing and senescence of Chinese kale. Transcriptome analysis unequivocally validates melatonin's efficacy in delaying leaf senescence in postharvest Chinese kale stored at 20 °C. Following a three-day storage period, the melatonin treatment group exhibited 1637 differentially expressed genes (DEGs) compared to the control group. DEG analysis elucidated that melatonin-induced antisenescence primarily governs phenylpropanoid biosynthesis, lipid metabolism, plant signal transduction, and calcium signal transduction. Melatonin treatment up-regulated core enzyme genes associated with general phenylpropanoid biosynthesis, flavonoid biosynthesis, and the α-linolenic acid biosynthesis pathway. It influenced the redirection of lignin metabolic flux, suppressed jasmonic acid and abscisic acid signal transduction, and concurrently stimulated auxin signal transduction. Additionally, melatonin treatment down-regulated RBOH expression and up-regulated genes encoding CaM, thereby influencing calcium signal transduction. This study underscores melatonin as a promising approach for delaying leaf senescence and provides insights into the mechanism of melatonin-mediated antisenescence in postharvest Chinese kale.

Optimization of an Efficient Direct Shoot Induction System and Histological Evaluation of Shoot Formation in Cucurbita maxima Duch

Improving plant regeneration ability and shortening regeneration time can promote the development of genetic transformation breeding technology for horticultural crops. We optimized several culture conditions, including explant type, mother plant genotype, and medium, to improve shoot formation in winter squash (Cucurbita maxima Duch.). Histological analysis of the occurrence of shoots was also carried out. The results indicate that cotyledon was the most suitable explant for inducing the shoot regeneration of winter squash. We found that ‘Jin-li’ had a shorter shoot induction time and a higher average number of shoots. The highest induction rate of 95.23% among the five lines. The average shoot induction rate of five lines was the highest (84.85%) on Murashige and Skoog (MS) medium supplemented with 2.0 mg/L 6-benzylaminopurine (6-BA) and 0.2 mg/L indole-3-acetic acid (IAA). We also found that there was an interaction between genotypes and induction media, and their interaction had a greater impact on the shoot induction rate than individual effects. Histological observation revealed that the induced shoots of winter squash cotyledons originated from subepidermal cells. We also found that the optimal medium for de novo root regeneration was 1/2 MS. We acclimatized and cultivated regenerated plants and harvested their fruits, which maintained the characteristics of mother plants. These findings lay an important foundation for further research on direct shoot regeneration and accelerate its application in winter squash genetic transformation.

Effect of Climate Change and Recent Droughts on Quantitative and Qualitative Performance of Horticultural Crops in Badghis

This study aimed to investigate the impact of climate change on horticultural crops in Badghis province, Afghanistan. Data was collected through a questionnaire completed by gardeners and experts in the horticulture department. Descriptive statistics are used to analyze the data, and the results showed that climate change had a significant negative impact on the performance of horticultural crops, including decreased yield and quality and an increase (33%) in plant pests and diseases. The study highlights the need for complete and comprehensive measures to mitigate the effects of climate change and recent droughts on horticulture in Badghis province. The majority of interviewers (51%) reported a decrease in yield and quality of their crops due to changes in temperature and rainfall patterns. In addition, many interviewers reported an increase in plant pests and diseases (54%), which they attributed to climate change. The study also found that orchards in Badghis have adopted some adaptation strategies, such as changing their planting schedules and using more efficient irrigation methods. However, these strategies are not enough to fully address the challenges posed by climate change.

A Review on Effects of Biofertilizers and Bio Capsules on Vegetative Growth, Flowering and Fruiting Attributes of Strawberry

This paper analyzes the impact of biofertilizers and bio capsules the vegetative growth, flowering, and fruiting attributes of strawberries (Fragaria x ananassa). Biofertilizers are natural substances containing beneficial microorganisms that enhance nutrient availability in the soil, while bio capsules encapsulate beneficial microbes for controlled release. Many researchers have concluded their positive finding with regards to application of various biofertilizers and biocapsules in strawberry as well as in other horticultural crops. This paper provides current findings and explains the role of biofertilizer and bio capsules and its effect on different stages of strawberry development. This review highlights the potential of these sustainable agricultural practices in optimizing strawberry cultivation in an eco-friendly way.

Species composition of Bactrocera fruit flies (Diptera: Tephritidae) and their parasitoids on horticultural commodities in Batu City and Malang District, East Java, Indonesia

Abstract. Setiawan Y, Hamdoen FM, Muhammad FN, Hata K, Tarno H, Wang J. 2024. Species composition of Bactrocera fruit flies (Diptera: Tephritidae) and their parasitoids on horticultural commodities in Batu City and Malang District, East Java, Indonesia. Biodiversitas 25: 305-311. Bactrocera Macquart, 1835 fruit flies (Diptera: Tephritidae) are among the most important pests in horticultural commodities worldwide, including horticultural crops in Indonesia. Trapping is suggested to control, eradicate, and suppress fruit flies. The presence of natural enemies is a very important factor in the indicators of agroecosystem balance. This study aimed to monitor the species composition of Bactrocera fruit flies and their parasitoids in several horticultural commodities such as apples, large chili, red guava, sweet citrus, and tomatoes in Batu City and Malang District. Trapping and host-rearing methods were used in this research. A total of 7,124 individuals of Bactrocera were collected using a Steiner trap baited with methyl eugenol. They consisted of six species: Bactrocera carambolae Drew & Hancock, 1994; Bactrocera cucurbitae (Coquillett, 1899); Bactrocera dorsalis (Hendel, 1912); Bactrocera verbascifoliae Drew & Hancock, 1994; Bactrocera papayae Drew & Hancock, 1994; and Bactrocera umbrosa (Fabricius, 1805). The B. carambolae, B. dorsalis, and B. papayae were the three predominant species collected using Steiner traps baited with methyl eugenol. Based on the host-rearing method, B. carambolae and B. dorsalis were found in red guava fruit. Only one parasitoid species, Opius sp., was found in red guava fruit. These results provide valuable insights into the distribution of Bactrocera on horticultural commodities in Batu City and Malang District and the potential challenges regarding parasitoid presence.

Placement of acidified digestate solid fraction as an efficient starter phosphorus fertilizer for horticulture crops

This study proposes employing acidified digestate solid fraction (DSF) as an effective P starter fertilizer for horticulture crops. Our investigation comprised two experiments to assess the effects of acidification and different application methods (mixed vs. acidified) of DSF on P use efficiency and root growth in horticulture crops. Acidification (7.5 % of H2SO4, ww−1) reduced the DSF pH from 9.6 to 1.6 and increased the P solubility from 14 % to 59 % of the total P. In the first experiment, we observed crop-specific responses to placement, with all ten crops exhibiting significantly higher P uptake when for acidified DSF, compared to untreated DSF mixed with the soil. Notably, root crops (carrot, onion, and fennel) and beans demonstrated the most favorable response to acidified DSF placement. The second experiment focused on six selected crops, comparing the effects of untreated DSF versus acidified DSF on root growth in rhizoboxes. Bean, pea, broccoli, carrot, and onion exhibited increased total root growth and in the soil surrounding the placement zone, due to higher P availability that boosted early-stage crop growth. Furthermore, the placement of acidified DSF also increased its sulfur fertilizer value. In conclusion, the placement of acidified DSF can make it an efficient phosphorus starter fertilizer. However, it is worth noting that the DSF has low density, and processing such as pelletization may be needed to facilitate its handling and allocation as a biobased fertilizer. Moreover, further studies are required to assess the effects on commercial yield, vegetable nutraceutical properties, and optimal application and acidification rates.

Utilization of treated wastewater derived from microalgae production for the irrigation of horticultural crops

Utilization of treated wastewater derived from microalgae production for the irrigation of horticultural crops

A TERRESTRIAL ISOPOD ( ARMADILLIDIUM ARCANGELII STROUHAL, 1929) AS A POTENTIAL AGRICULTURAL PEST: A CASE STUDY ON MELON CROP (CUCUMIS MELO L.) IN ITALY

Terrestrial isopods are generally considered as detritivore invertebrates, but in recent years and in different parts of the world they seem to become potential agricultural pests for different crops. The crops affected so far have been mainly arable crops, but damages to few horticultural crops were also documented. Until now, no referenced problems with isopods as crop pests had ever occurred in Italy. In March/April 2023 on two organic farms in northern Italy newly transplanted seedlings of smooth melon in greenhouses were damaged by isopods. Among farms, the loss was estimated between 40% and 50% of the seedlings. The isopod that caused the damage was identified as Armadillidium arcangelii, and, until now, the species had never been reported as a crop pest. Key Words: New potential pest, Armadillidium arcangelii, terrestrial isopod, melon crop

The Effect and Potential Mechanism of Fulvic Acid on Flavonoids in Lemon Leaves

Citrus limon (L.) Burm. f. is a horticultural crop known for its abundance of valuable secondary metabolites, including flavonoids, which are found in its fruits and leaves. Our previous research has shown that treating C. limon with fulvic acid (FA) can enhance the levels of vitamin C, total acid, total sugar, total flavonoids, and phenols in its fruits as well as the volatiles and total flavonoids in its leaves. In this current study, we established a method to analyze eight specific flavonoids in lemon leaves and evaluated the impact of irrigation with FA on the content of these flavonoids over a six-month period using HPLC-DAD/MS analysis. Moreover, we investigated the potential mechanisms of FA through ELISA and q-PCR methods. The results indicated that FA increased the contents of four flavonoids, namely, isoorientin, eriocitrin, vitexin, and rutin, and promoted the activity and gene expression of phenylalanineammonialyase (PAL), 4-coumaric acid coenzyme A ligase (4CL), chalcone synthase (CHS), flavonoid 3′-hydroxylase (F3′H), and flavonol synthase (FLS). Furthermore, the relationship between flavonoid content and the activities of biosynthetic enzymes was analyzed using orthogonal partial least squares discriminant analysis (OPLS-DA), which revealed a positive correlation between seven flavonoid levels and the activity of five biosynthetic enzymes under FA treatment.

Occurrence of Pseudomonas cichorii Causing Midrib Rot of Lettuce Under Hydroponic Cultivation in Chile

In Chile, lettuce is the vegetable that has increased in cultivated area the most in recent years, reaching 8,309 ha. The Coquimbo Region contributes the most to this growth in production with 3,284 ha in 2022 (ODEPA 2023). Most lettuce is grown under open field conditions, but there is significant production in greenhouses and an increase in hydroponic production systems (INIA 2017). During April to June 2021 and 2022 in the Coquimbo Region, butterhead-type lettuce seedlings (Lactuca sativa) cv. Neil, cultivated under a hydroponic system, showed severe brown to black lesions in the leaves and midrib (Figure S1). To determine the etiology of this problem, samples of diseased plants were taken. Pieces of symptomatic tissue were macerated, and the extract was spread on nutrient agar (NA) and on King's B medium (KB) and incubated at 23°C for 48 h. The bacterial colonies observed were predominantly circular, creamy-white in color with irregular margins and fluorescent in KB medium. Isolates were gram-negative strictly aerobic. LOPAT test (Lelliot et al. 1966) results of two selected isolates were: levan production (-), oxidase reaction (+), potato soft rot (-), arginine dihydrolase production (-), and tobacco hypersensitivity (+), which corresponds to the profile of Pseudomonas cichorii. Molecular identification was performed through amplification and sequencing of the 16S rRNA (GenBank Accessions No. OR540674 to OR540675), gyrB and rpoD genes (Hwang et al. 2005; Sarkar and Guttmann 2004) (GenBank Accessions No. OR558279 to OR558282). BLAST analysis of the 16S rRNA gene of the isolates resulted in a match with a 99.86% identity with P. cichorii type strain ATCC 10857 (NR_112070.1). BLAST analysis of gyrB and rpoD resulted in a match with a 100% (630/630 bp) and >99% (546/550 bp) identity respectively, with strains of P. cichorii. Five six-month-old lettuce plants cv. Desert Storm were pricked in the midrib with a toothpick smeared with a fresh colony grown on KB medium. Seven days after inoculation, the plants showed dark brown, watery lesions, characteristic of damage caused by P. cichorii (Figure S1). Bacteria were isolated again from the inoculated plants and were identified as P. cichorii using LOPAT and molecular identification techniques. Midrib rot caused by P. cichorii was reported as an emerging disease of greenhouse-grown lettuce by Cottyn et al. (2009). In Chile, P. cichorii was previously described affecting nectarine fruits (Pinto de Torres and Carreño Ibañez 1983) and reported as a pathogen of lettuce among others horticultural crops by Servicio Agrícola y Ganadero of the Government of Chile (Acuña 2008), but this is the first report of P. cichorii affecting hydroponic lettuce plants in Chile. These results will be the basis of future studies to evaluate the origin of the infection, the potential dissemination, and the implementation of disease management to avoid the damage caused by this bacterium in hydroponic systems in this crop of growing importance in Chile.