Potato Seedlings Research Articles

Impacts of Light Exposure and Soil Covering on Sweet Potato Storage Roots in a Novel Soilless Culture System

Soilless culture systems, which promote plant growth and enable the precise control of the root-zone environment, have yet to be fully established for sweet potatoes. In this study, we developed a soilless culture system and examined the effects of soil covering and light exposure on the storage roots of sweet potatoes. Sweet potato seedlings with induced storage roots were transplanted into five systems: a previously developed pot-based hydroponics system (Pot), an improved version with storage roots enclosed in a plastic box and covered with a soil sheet (SS), the SS system without the soil sheet (SD), the SD system with light exposure to storage roots after 54 days (SL), and a deep flow technique (DFT) hydroponics system. Our study enabled the time-course observation of storage root enlargement in the SS, SD, and SL systems. In the SL system, light exposure suppressed the storage root enlargement and reduced epidermal redness. No storage root enlargement was observed in the DFT system, even at 151 days after transplantation. Light exposure in the SL system increased the chlorophyll and total phenolic contents in the cortex beneath the epidermis, while the starch content was the lowest in this system. These findings indicate that the developed system can induce normal storage root enlargement without soil. Additionally, the observed changes in growth and composition due to light exposure suggest that this system is effective for controlling the root-zone environment of sweet potatoes.

Growing Vigorous Potato Seedlings in Plug Trays

AbstractRaising vigorous and healthy potato seedlings from hybrid true potato seeds (TPS) under nursery conditions is critical for ease of field transplanting and seedling crop establishment as well as for a productive seed or ware crop. The use of plugs in seedling production systems is an important technique utilised to ease transplanting of seedlings and refine seedling production in seedling nurseries. While holding multiple advantages over other transplant production systems, multiple factors still influence the success of seedling production in plug trays. In this study, we explore the effects of substrate properties, type and volume; watering intervals; and nitrogen (N) and phosphorus (P) levels in nutrient solution on seedling vigour attributes in potato seedlings grown in plug trays under climate room conditions. The choice of substrate strongly influenced seedling attributes with more favourable performance in substrates with higher water holding capacity. Increasing plug volume also enhanced seedling attributes including dry biomass, leaf area and root to shoot ratios such that seedling performance was best in plug volumes > 22.5 cm3. A watering schedule with a high frequency was more favourable considering that longer intervals between watering events led to significant declines in seedling attributes. While the effects of increased P in solution were not conclusive, depending on genotype, increasing N in solution led to enhanced seedling attributes, with a nutrient sufficiency met at 200 mg L−1 N in solution. These findings further contribute to the current knowledge on factors influencing success in seedling production of potato seedlings developed from hybrid true potato seeds.

Potato growth, nitrogen balance, quality, and productivity response to water-nitrogen regulation in a cold and arid environment.

The pervasively imprudent practices of irrigation and nitrogen (N) application within Oasis Cool Irrigation zones have led to significant soil nitrogen loss and a marked decrease in water and nitrogen use efficiency. To address this concern, a comprehensive field experiment was conducted from April to September in 2023 to investigate the impact of varying degrees of water and fertilization regulation strategies on pivotal parameters including potato yield, quality, nitrogen balance, and water-nitrogen use efficiency. The experimental design incorporated two water deficit degrees at potato seedling (W1, 55%-65% of Field Capacity (FC); W2, 45%-55% of FC), and four distinct nitrogen application gradients (N0, 0 kg ha-1 of N; N1, 130 kg ha-1 of N; N2, 185 kg ha-1 of N; N3, 240 kg ha-1 of N). A control was also included, comprising N0 nitrogen application and full irrigation (W0, 65%-75% of FC), totally eight treatments and one check. The results indicated that the tuber yield, plant dry matter accumulation, plant height, plant stem, and leaf area index increased with higher nitrogen fertilizer application and irrigation volume. However, tuber starch content, vitamin C, and protein content initially increased and then decreased, while reducing sugar content consistently decreased. Except for W1N2 treatment, the irrigation water use efficiency increased as the N application rate rose, while the nitrogen partial factor productivity, crop nitrogen use efficiency and soil nitrogen use efficiency decreased with an increase in N fertilizer application. The W1N2 treatment resulted in a higher yield (43.16 t ha-1), highest crop nitrogen use efficiency (0.95) and systematic nitrogen use efficiency (0.72),while maintaining moderate levels of soil nitrate and ammonium nitrogen. Therefore, through the construction of an integrated evaluation index (IEI), the W1N2 treatment of mild water deficit (55%-65% of FC) at potato seedling combined with the medium nitrogen application (185 kg ha-1 of N) has the highest IEI (0.978), it was recommended as the optimal water-nitrogen regulation and management strategies to facilitate high-yield, high-efficiency, and environmentally sustainable potato production in the cold and arid oasis areas of northwest China.

Design and Experiment of Compound Transplanter for Sweet Potato Seedling Belt

To address the issues of high labor intensity, excessive manpower requirements, low planting spacing qualification rates, low planting depth qualification rates, and low operational efficiency associated with sweet potato transplanting, a sweet potato seedling belt transplanter has been designed. This machine can perform multiple processes: precision tillage and ridge shaping, orderly seedling feeding from rolls, the efficient separation of seedlings from the belt, flexible gripping and shaping, precise soil covering and the mechanism of exposing seedling tips. A three-factor, three-level orthogonal test was carried out using the forward speed of the machine, the pitch of the screw belt and the rotational speed of the screw as the influencing factors of the performance test, and the qualified rate of planting spacing and the qualified rate of planting depth as the evaluation indexes. The test results indicated that the significance order of the factors affecting the qualification rate for planting spacing with the optimal combination of factors was as follows: a forward speed of 0.3 m·s−1, a ribbon spacing of 60 mm, and a screw speed of 160 rpm. Field trials confirmed that under optimal conditions, the average qualification rate for planting spacing was 90.37%, meeting relevant technical standards and agronomic requirements.

Design and Test of Potato Seedling Killing and Residual Film Recycling Integrated Machine

Plastic film mulching technology can effectively enhance crop yield and quality, and the use of mulch has been increasing in recent years; however, the problem of mulch residue is worsening due to the large amount of recycling work and slow natural degradation. In this study, a potato seedling killing and residual film recycling machine is designed to provide good working conditions for potato harvesters before harvesting in response to the problems of difficult separation of film tangles, the low net rate of recycling due to the mixing of residual film with soil, and the high soil content in residual film recycling operations in northwest China. The machine is based on the potato monoculture and double row planting mode in Gansu area. This paper puts forward the overall design scheme and carries out the theoretical analysis and parameter determination of the key components, such as the seedling killing device, the film surface cleaning device, the film unloading device, and so on. Using EDEM software to carry out the virtual simulation test and Design-Expert13 to analyze the test results, we determined the optimal working scheme for the machine, with a forward speed of 0.8 m/s, a film gap of 125 mm, and a spiral stirrer speed of 600 r/min. Based on a field test for verification, the test results show that the machine’s residual film recovery rate was 83.3%, the impurity rate was 3.8%, and the rate of injury to the potatoes was 1.4%. The machine meets the requirements of national and industry standards, and it can simultaneously realize straw crushing, film surface cleaning, residual film recycling, and hydraulic film unloading operations, with better operating results and while reaching the expected results. It can also provide a reference for the design and testing of a seeding and residual film recycling machine.

<i>Solanum tuberosum</i> L. phytoene synthase genes (<i>StPSY1, StPSY2, StPSY3</i>) participate in the potato plant’s response to cold stress

The structure and phylogeny of the genes StPSY1, StPSY2 and StPSY3, encoding phytoene synthases from Solanum tuberosum L., were characterized. The expression of these genes in potato seedlings was studied in response to exposure to cold stress in the dark phase of the diurnal cycle as an imitation of night cooling. It was found that all three genes are activated when the temperature decreases, and the greatest response is observed for StPSY1. The response of the StPSY3 gene to cold stress and photoperiod has been demonstrated for the first time. A search was carried out for cis-regulatory elements in the promoter region and 5´-UTR of the StPSY genes and it was shown that the regulation of all three genes is associated with the response to light. The high level of low-temperature activation of the StPSY1 gene may be associated with the presence of cis-elements associated with sensitivity to cold and ABA.

Bed, ridge and planting configurations influence crop performance in field-transplanted hybrid potato crops

Current cultivation practices for field transplanted potato crops grown from nursery-raised hybrid potato seedlings are mostly borrowed from the tuber-based conventional system. Most studies on field performance of field transplanted seedling crops have largely reported the use of ridged rows and in exceptional cases, the use of beds. It is therefore critical to assess the feasibility of the use of alternative ridge or bed systems for cultivation of field-transplanted nursery-raised potato seedlings considering the differences in physiological behaviour of crops grown from different starting materials. This study assessed the effects of six systems which included bed and ridge systems of different dimensions and planting configurations for field transplanted seedling crops. Field crop establishment, canopy growth and development as well as yield and yield components were assessed. In general, systems that boasted high plant densities resulted in faster canopy development and higher number of tubers and tuber yield. Bed systems (raised and flat beds; 8.0 plants m−2) therefore gave the highest numbers of tubers and tuber yield across all treatments. These systems also produced the most tubers in all tuber size classes resulting in the highest yields in all classes. Standard ridge systems (full- and half ridges; 0.75 m row distance), had the lowest plant populations (5.3 plants m−2) which resulted almost always in fewer tubers and lower yield. Other ridge systems (0.9-m and 0.5-m ridge systems), although having higher plant densities than the standard ridge systems (8.9 and 8.0 plants m−2, respectively) still performed poorer than the bed systems. The small and compact ridges in the 0.5-m ridge system and the compact arrangement of plants in the 0.9-m ridge system caused these effects. Conclusively, based on this study, productivity in field transplanting systems is highly influenced by plant density. Further, cultivation systems boasting higher planting densities should be recommended when the goal for production is to produce large quantities of seed tubers (> 35; ≤ 50 mm).

A Highly Accurate Detection Platform for Potato Seedling Canopy in Intelligent Agriculture Based on Phased Array LiDAR Technology

A Highly Accurate Detection Platform for Potato Seedling Canopy in Intelligent Agriculture Based on Phased Array LiDAR Technology

Dynamics of physiological and biochemical effects of heat, drought and combined stress on potato seedlings

BackgroundHeat and drought stresses usually occur together in nature, and both are expected to increase in frequency and intensity as a result of climate change. The synergistic impacts of these compound climate extremes on potatoes are far from the effects of individual stresses. However, the dynamics of the effects of combined heat and drought stresses on potato physiology and biochemistry have yet to be thoroughly assessed. To elucidate this point, we set up a pot experiment using ‘Atlantic’ potato seedlings as test material. A total of six treatments were set up: CK (normal growth conditions: 21 ℃, 0 PEG), A1B1 (31 ℃, 20% PEG), A1B2 (31 ℃, 10% PEG), A1B3 (31 ℃, 0 PEG), A2B1 (21 ℃, 20% PEG), and A2B2 (21 ℃, 10% PEG), and 15 physiological indices were determined with the stress time of 0, 6, 12 and 18 days.ResultsAfter 18 days of stress, the phenotype of potato seedlings was significantly different. Compared with CK, the thickness of potato leaves and palisade tissue increased under heat and drought stress, and the combined stress reduced the photosynthetic efficiency of potato leaves. In all treatments except CK, the chlorophyll content decreased significantly, the antioxidant enzyme activity increased first and then decreased, and the relative conductivity and malondialdehyde content increased significantly. The heat and combined treatment made the content of the osmotic regulator first increase and then decrease, while the treatment of 21 ℃ had no significant change. According to the correlation, principal component and interaction analysis, both heat and drought treatment had significant effects on each index, and the longer the stress time, the greater the effect, and the effect of combined stress was greater than that of single stress. However, after 6 days of stress, the activity of antioxidant enzymes and the content of transparent regulatory substances increased.ConclusionsIn conclusion, potato can cope with heat, drought and combined stress by adjusting leaf tissue structure, antioxidant enzyme activity and osmotic regulatory substances in a short time.Graphical

A deep learning-based method for estimating the main stem length of sweet potato seedlings

The length of sweet potato seedling main stems is critical for harvest decisions, but accurately measuring it is challenging due to leaf occlusion and self-curvature. This study proposes a method for stem reconstruction and length estimation using a two-stage classifier, feature extraction, and semantic segmentation to obtain stem masks. Image processing separates clustered skeletons into singular lines for detailed analysis. Object detection identifies roots, stem-leaf intersections, and establishes a search relationship among segments. Stems are reconstructed based on directional, distance, and curvature constraints, then divided into four parts for length estimation using stereo depth information. Experimental results demonstrate effectiveness under various conditions: un-occluded, partially occluded, curved stems, and low-density clusters. Median length estimation error is 1.7 cm, with maximum and minimum errors of 3.2 cm and 0.3 cm respectively. This automated method provides a reliable solution for sweet potato seedling harvest and grading.

Cytokinin Oxidase (CKX) Family Members in Potato (Solanum tuberosum): Genome-Wide Identification and Expression Patterns at Seedling Stage under Stress

Cytokinin (CK) is an important hormone that regulates cell differentiation. The CK content in plants is regulated by cytokinin oxidase (CKX), an important enzyme that participates in hormone-regulated pathways. Additionally, CKXs comprise a large family of enzymes, but little information exists on the CKXs in potato (Solanum tuberosum). In this study, nine CKXs were identified in the potato genome and named StCKX01-09, according to their order on the linkage groups (LGs). They belong to six subfamilies, and the members within the respective subfamilies had similar motifs, a similar gene structure, and similar cis-acting elements. Additionally, the CKXs from four other species, including Arabidopsis, rice (Oryza sativa), soybean (Glycine max), and maize (Zea mays), were also divided into six subfamilies, while members within each subfamily had similar types of motifs. Moreover, the potato StCKXs were shown to influence plant hormones and stress-related factors. StCKXs were collinear, with one CKX in Arabidopsis and five CKXs in Glycine max. Quantitative real-time PCR (qRT-PCR) revealed tissue-specific expression patterns in the potato seedlings and changes in the expression levels in response to stress. Furthermore, the cytokinin content and CKX enzyme activity were shown to be regulated by StCKXs. This study provides detailed information that can help future endeavors in the molecular breeding of potato (Solanum tuberosum).

Involvement of Nitric Oxide in Biochemical and Physiological Response of Potato Seedling Under Cold Stress

Involvement of Nitric Oxide in Biochemical and Physiological Response of Potato Seedling Under Cold Stress

Design and control of a side dense transplanting machine for sweet potato seedlings on mulch film

At present, China is the leading country in sweet potato cultivation worldwide. However, there are still several problems such as high labor intensity, low efficiency of manual transplanting, and lack of machinery for side transplanting for sweet potato seedlings on mulch film. Therefore, a side dense transplanting machine for sweet potato seedlings on mulch film is designed, using a multi-row side transplanting method. It is mainly composed of a transplanting device, a seedling conveying device, a traveling device, and a control system. Based on the agronomic requirements for sweet potato transplanting, the study focuses on the structure and working principle of the complete machine. It involves the detailed structural design and motion analysis of the crank-rocker and cam of the transplanting device. Based on the sweet potato seedlings transportation plan, parameters such as the vertical height of the seedling conveying device, the size of the support frame, and the relative relationship between position of the transplanting device are determined. To ensure the smooth transplantation of sweet potato seedlings, the motor parameters required for each device are calculated and determined. An Arduino control system is developed to manage the coordinated movement of each device. Positioning components are integrated to ensure accurate coordination between the transplanting device and the seedling conveying device. This setup enables the seedling claws to pick sweet potato seedlings and perform the side transplanting on the mulch film. Field test results show the missed rate of seedlings, the qualified rate of transplanting and the qualified rate of transplanting depth are 4.13 %, 91.62 % and 93.86 % respectively. The transplant spacing coefficient of variation and the average spacing between seedlings are 1.90 and 177.06 mm respectively. All indicators of the transplanting machine meet the agronomic requirements for side dense transplanting for sweet potato seedlings on mulch film. The transplanting machine is integrated with sweet potato seedling transplanting agronomy, achieving mechanized transplanting of sweet potato seedlings, reducing labor intensity, and promoting the quality and efficiency of sweet potato production. This research provides a reference for the development of sweet potato seedlings transplanting equipment.

Root Zone Water Management Effects on Soil Hydrothermal Properties and Sweet Potato Yield.

Sufficient soil moisture is required to ensure the successful transplantation of sweet potato seedlings. Thus, reasonable water management is essential for achieving high quality and yield in sweet potato production. We conducted field experiments in northern China, planted on 18 May and harvested on 18 October 2021, at the Nancun Experimental Base of Qingdao Agricultural University. Three water management treatments were tested for sweet potato seedlings after transplanting: hole irrigation (W1), optimized drip irrigation (W2), and traditional drip irrigation (W3). The variation characteristics of soil volumetric water content, soil temperature, and soil CO2 concentration in the root zone were monitored in situ for 0-50 days. The agronomy, root morphology, photosynthetic parameters, 13C accumulation, yield, and yield components of sweet potato were determined. The results showed that soil VWC was maintained at 22-25% and 27-32% in the hole irrigation and combined drip irrigation treatments, respectively, from 0 to 30 days after transplanting. However, there was no significant difference between the traditional (W3) and optimized (W2) drip irrigation systems. From 30 to 50 days after transplanting, the VWC decreased significantly in all treatments, with significant differences among all treatments. Soil CO2 concentrations were positively correlated with VWC from 0 to 30 days after transplanting but gradually increased from 30 to 50 days, with significant differences among treatments. Soil temperature varied with fluctuations in air temperature, with no significant differences among treatments. Sweet potato survival rates were significantly lower in the hole irrigation treatments than in the drip irrigation treatments, with no significant difference between W2 and W3. The aboveground biomass, photosynthetic parameters, and leaf area index were significantly higher under drip irrigation than under hole irrigation, and values were higher in W3 than in W2. However, the total root length, root volume, and 13C partitioning rate were higher in W2 than in W3. These findings suggest that excessive drip irrigation can lead to an imbalance in sweet potato reservoir sources. Compared with W1, the W2 and W3 treatments exhibited significant yield increases of 42.98% and 36.49%, respectively. The W2 treatment had the lowest sweet potato deformity rate.

Screening of Indicators to Evaluate the Overwintering Growth of Leaf-Vegetable Sweet Potato Seedlings and Their Main Influential Factors

Screening of Indicators to Evaluate the Overwintering Growth of Leaf-Vegetable Sweet Potato Seedlings and Their Main Influential Factors

Identification of cysteine-rich receptor-like kinase gene family in potato: revealed StCRLK9 in response to heat, salt and drought stresses.

The investigation into cysteine-rich receptor-like kinases (CRLKs) holds pivotal significance as these conserved, upstream signalling molecules intricately regulate fundamental biological processes such as plant growth, development and stress adaptation. This study undertakes a comprehensive characterisation of CRLKs in Solanum tuberosum (potato), a staple food crop of immense economic importance. Employing comparative genomics and evolutionary analyses, we identified 10 distinct CRLK genes in potato. Further categorisation into three major groups based on sequence similarity was performed. Each CRLK member in potato was systematically named according to its chromosomal position. Multiple sequence alignment and phylogenetic analyses unveiled conserved gene structures and motifs within the same groups. The genomic distribution of CRLKs was observed across Chromosomes 2-5, 8 and 12. Gene duplication analysis highlighted a noteworthy trend, with most gene pairs exhibiting a Ka/Ks ratio greater than one, indicating positive selection of StCRLKs in potato. Salt and drought stresses significantly impacted peroxidase and catalase activities in potato seedlings. The presence of diverse cis -regulatory elements, including hormone-responsive elements, underscored their involvement in myriad biotic and abiotic stress responses. Interestingly, interactions between the phytohormone auxin and CRLK proteins unveiled a potential auxin-mediated regulatory mechanism. A holistic approach combining transcriptomics and quantitative PCR validation identified StCRLK9 as a potential candidate involved in plant response to heat, salt and drought stresses. This study lays a robust foundation for future research on the functional roles of the CRLK gene family in potatoes, offering valuable insights into their diverse regulatory mechanisms and potential applications in stress management.

Research on improved YOLOv8n based potato seedling detection in UAV remote sensing images.

Accurate detection of potato seedlings is crucial for obtaining information on potato seedlings and ultimately increasing potato yield. This study aims to enhance the detection of potato seedlings in drone-captured images through a novel lightweight model. We established a dataset of drone-captured images of potato seedlings and proposed the VBGS-YOLOv8n model, an improved version of YOLOv8n. This model employs a lighter VanillaNet as the backbone network in-stead of the original YOLOv8n model. To address the small target features of potato seedlings, we introduced a weighted bidirectional feature pyramid network to replace the path aggregation network, reducing information loss between network layers, facilitating rapid multi-scale feature fusion, and enhancing detection performance. Additionally, we incorporated GSConv and Slim-neck designs at the Neck section to balance accuracy while reducing model complexity. The VBGS-YOLOv8n model, with 1,524,943 parameters and 4.2 billion FLOPs, achieves a precision of 97.1%, a mean average precision of 98.4%, and an inference time of 2.0ms. Comparative tests reveal that VBGS-YOLOv8n strikes a balance between detection accuracy, speed, and model efficiency compared to YOLOv8 and other mainstream networks. Specifically, compared to YOLOv8, the model parameters and FLOPs are reduced by 51.7% and 52.8% respectively, while precision and a mean average precision are improved by 1.4% and 0.8% respectively, and the inference time is reduced by 31.0%. Comparative tests with mainstream models, including YOLOv7, YOLOv5, RetinaNet, and QueryDet, demonstrate that VBGS-YOLOv8n outperforms these models in terms of detection accuracy, speed, and efficiency. The research highlights the effectiveness of VBGS-YOLOv8n in the efficient detection of potato seedlings in drone remote sensing images, providing a valuable reference for subsequent identification and deployment on mobile devices.

Potato Solanum tuberosum L. Phytoene Synthase Genes (StPSY1, StPSY2, and StPSY3) Are Involved in the Plant Response to Cold Stress.

The structure and phylogeny of the Solanum tuberosum L. phytoene synthase genes StPSY1, StPSY2, and StPSY3 were characterized. Their expression was studied in potato seedlings exposed to cold stress in the dark phase of the diurnal cycle to simulate night cooling. All of the three genes were activated as the temperature decreased, and the greatest response was observed for StPSY1. StPSY3 was for the first time shown to respond to cold stress and photoperiod. A search for cis-regulatory elements was carried out in the promoter regions and 5'-UTRs of the StPSY genes, and the regulation of all three genes proved associated with the response to light. A high level of cold-induced activation of StPSY1 was tentatively attributed to the presence of cis elements associated with sensitivity to cold and ABA.

Shoot Growth Parameters of Potato Seedlings are Determined by Light and Temperature Conditions

Raising quality hybrid potato true seedlings — derived from hybrid true potato seeds (TPS) — for field transplanting is a critical aspect contributing to the success in cultivating field-transplanted hybrid potato seedling-based crops. Various critical seedling vigour attributes must be defined and enhanced to improve plant performance as well as plant response and adaptation to field conditions after field transplanting. Moreover, additional attributes besides leaf number and stem length should be defined to design selection criteria for “transplantability” of potato seedlings. To assess these attributes and their robustness under different environmental conditions, seedlings of hybrid genotypes were raised under contrasting daylengths, light intensities and temperature regimes, and combinations of these factors, and the effects of these factors (or factor combinations) on seedling vigour and its attributes were quantified. Increased light intensity and daylight integral (DLI) enhanced leaf parameters and increased biomass under long-day conditions, but seedlings did not show conclusive responses under short-day conditions in most attributes. Higher temperatures increased biomass and constant day and night temperatures enhanced compaction of shoot architecture as did higher light intensities — to a greater extent. These results highlight additional seedling vigour attributes including leaf area parameters and seedling biomass which should be utilised to determine “transplantability” of hybrid potato seedlings. Additionally, the results provide a starting point for further research on optimising hybrid seedling production for field transplanting.

First report of Pectobacterium polaris causing aerial stem rot of potato in Mexico.

In Mexico, potato (Solanum tuberosum L.) is one of the most important vegetable crops for local consumption and industry. More than 1.8 million tons of potatoes are produced annually, of which the state of Sinaloa contributes with 21.5% (SIAP. 2022). In January 2020, potato plants (cv. FL1867) showing aerial stem rot symptoms were observed in a commercial field from the Santa Rosa Valley, in Northern Sinaloa with an incidence of 36%. Putative pectolytic bacteria showing pitting on crystal violet pectate (CVP) plates were restreaked and purified onto Nutritive Agar (NA) medium at 28°C. Four independent isolates were obtained (L25F-83, L25F-105, L25F-115, and L25F-125) from four symptomatic stems with biochemical and morphological characteristics related to Pectobacterium, such as catalase positive, oxidase negative, pectinolytic activity, Gram-negative and non-fluorescent in B-King medium. Bacterial gDNA was used for amplification and sequencing of two housekeeping genes (dnaX and leuS) (Portier et al. 2019). The nucleotide sequence identity between our isolates was 100% with both housekeeping genes (dnaX, OP376536-OP376539 and leuS, OP376540-OP376543). The BLASTn analysis of dnaX gene shared 98.98% and 99.19% identity with two soft-rot-causing bacterial strains NIBIO1006T (CP017481) and NIBIO1392 (CP017482) of Pectobacterium polaris, respectively; and with leuS gene shared 99.56% identity with P. polaris type strain NIBIO1006T. To further validate the identification, two strains, S5 (isolate L25F-105) and S6 (L25F-125), were selected for whole genome sequencing (WGS). The ANI values for closely related species were calculated using the Orthologous Average Nucleotide Identity (Ortho-ANI) Software Tool (OAT) (Lee et al. 2016). The Type (Strain) Genome Server (TYGS) was used for accurate genome-based taxonomy (https://tygs.dsmz.de) (Meier-Kolthoff et al. 2019). The genomes of P. polaris strains S5 (4811345 pb, GC=52%, AULSZ000000000) and S6 (4809754 pb, GC=52%, JAULTA000000000) revealed 96.86% and 96.07% Ortho-ANI and 73.6% and 66.5% dDDH with P. polaris type strain NIBIO1006T and P. parvum strain CFBP8630, respectively. The MLSA was performed on concatenated complete sequences of dnaX (OR470476, OR470477), leuS (OR470484, OR470485), recA (OR470488, OR470488), acnA (OR470474, OR470475), gapA (OR470478, OR470479), gyrA (OR470480, OR470481), icdA (OR470482, OR470483), proA (OR470486, OR470487), and rpoA genes (OR470490, OR470491). The consensus tree, constructed using the maximum likelihood method (MEGA 7.0), clustered strains S5 and S6 with P. polaris strains NIBIO1006T and NIBIO1392. The four isolates resulted pathogenic in tuber slices and potato seedlings (cv. Fianna) 24 and 72 h, respectively, after being inoculated with 30 µL bacterial suspension (1 X 108 CFU/ml) and incubated at 28 °C and 85% relative humidity. Bacterial colonies were reisolated from the affected tissue and identified with the same PCR primers as described above. Accordingly, P. polaris isolates S5 and S6, fulfill Koch's postulates for aerial stem rot of potato. To our knowledge, this is the first report of P. polaris causing aerial stem rot of potato in Mexico. This bacterium could be a significant threat to the local potato producers; therefore, an accurate and sensitive method of detection and epidemiological studies are needed to support an effective disease diagnosis and management program.