Peanut Cultivars Research Articles

Transcriptome Analysis Deciphers the Underlying Molecular Mechanism of Peanut Lateral Branch Angle Formation Using Erect Branching Mutant.

Background The growth habit (GH), also named the branching habit, is an important agronomic trait of peanut and mainly determined by the lateral branch angle (LBA). The branching habit is closely related to peanut mechanized farming, pegging, yield, and disease management. Objectives However, the molecular basis underlying peanut LBA needs to be uncovered. Methods In the present study, an erect branching peanut mutant, eg06g, was obtained via 60Co γ-ray-radiating mutagenesis of a spreading-type peanut cultivar, Georgia-06G (G06G). RNA-seq was performed to compare the transcriptome variation of the upper sides and lower sides of the lateral branch of eg06g and G06G. Results In total, 4908 differentially expressed genes (DEGs) and 5833 DEGs were identified between eg06g and G06G from the lower sides and upper sides of the lateral branch, respectively. GO, KEGG, and clustering enrichment analysis indicated that the carbohydrate metabolic process, cell wall organization or biogenesis, and plant hormone signal transduction were mainly enriched in eg06g. Conclusions Further analysis showed that the genes involved in starch biosynthesis were upregulated in eg06g, which contributed to amyloplast sedimentation and gravity perception. Auxin homeostasis and transport-related genes were found to be upregulated in eg06g, which altered the redistribution of auxin in eg06g and in turn triggered apoplastic acidification and activated cell wall modification-related enzymes, leading to tiller angle establishment through the promotion of cell elongation at the lower side of the lateral branch. In addition, cytokinin and GA also demonstrated synergistic action to finely regulate the formation of peanut lateral branch angles. Collectively, our findings provide new insights into the molecular regulation of peanut LBA and present genetic materials for breeding peanut cultivars with ideotypes.

Studying the biochemical composition of peanut accessions from the VIR collection

Background. Peanut is one of the most important oil crops for food purposes. Natural peanut butter contains two unsaturated fatty acids, oleic and linoleic, which make up to 80% of the total fatty acid content in peanut oil. The quality of oil depends on the ratio between these two acids. Analyzing the diversity of oil content and fatty acid composition in peanut accessions preserved at VIR and assessing the effect of soil, climate, and other factors on these characters is vital for the development of new peanut cultivars rich in oil. Materials and methods. Peanut germplasm accessions were studied for their biochemical composition of fatty acids and the content of oil and protein. The accessions were reproduced for three years (2019–2021) at two ecogeographic locations: in Krasnodar Territory, and Astrakhan Province. Cv. ‘Otradokubansky’ was used as a reference. ANOVA was applied for statistical data processing. Results and discussion. The percentage composition of 18 fatty acids was calculated in peanut oil, with oleic and linoleic acids dominating. The content of oleic acid depended on the genotype for 42–53%, and that of linoleic acid, for 50–71%. The latter was also influenced by the place and year of cultivation. The ranges of variation over the three years of studies in Krasnodar Territory were 35.4–57.6% for oleic acid, and 18.3–38.1% for linoleic acid, whereas in Astrakhan Province they were 33.4–51.2%, and 30.9–42.7%, respectively. Under unfavorable conditions, the content of oleic acid in peanut prevailed. The oil content depended on the genotype for 81%, and its percentage was 32.0–44.4%.

Effects of continuous and transgenerational rearing in peanut leaves on the performance and enzyme activity of Spodoptera frugiperda (Lepidoptera: Noctuidae).

The invasive fall armyworm (FAW), Spodoptera frugiperda, is a polyphagous pest that significantly threatens crops worldwide. FAW may undergo adaptation, enhancing its ability to infect specific plant hosts. However, there is limited knowledge on this topic. After 8 generations of constant rearing on peanut leaves, the performance and enzyme activities of FAW were investigated in this study. Compared to FAW fed on the peanut cultivars 'Fuhua 8' and 'Quanhonghua 1' for 2 generations, those grown on leaves for 5 to 8 generations had significantly shorter pre-adult development times and total preoviposition periods. Fecundity also increased significantly, resulting in an overall improvement in population fitness as measured by demographic parameters. However, the F2 generation of FAW fed on corn leaves outperformed the F8 generation of FAW fed on peanut leaves. In the F2 generation, the FAW peanut population exhibited 30-55% supernumerary larval molts, which decreased substantially in the F5 and F8 generations. Notably, supernumerary larval molts displayed pupation and emergence rates comparable to normal larvae, regardless of the peanut cultivar or rearing generation. The activities of lipase and acetylcholinesterase increased significantly from the F2 to F8 generations, showing substantial negative and positive correlations with larval development time and fecundity, respectively. In conclusion, FAW demonstrated inferior performance on peanut leaves compared to corn leaves, despite its performance was significantly improved after 5 to 8 generations of acclimation. These results suggest that corn will continue to be the primary target crop for FAW in China.

Cultivating resilience: use of water deficit to prime peanut production and improve water stress tolerance

Regulated deficit irrigation is a potential strategy for priming peanut plants to improve their acclimation to water stress. To assess possible effects of priming and develop an effective water stress priming strategy, greenhouse experiments were conducted to compare primed and non-primed peanut cultivars, C7616 and TUFRunner ‘511’TM, to subsequent water stress. Plants were divided into 1) controls with daily irrigation to field capacity throughout the entire growth cycle, 2) non-primed plants receiving daily irrigation up to 55 to 65 days after planting (DAP), followed by exposure to mid-season water stress, and 3) primed plants that received 50% of the control irrigation either from 5-45 DAP (long-term priming), or 20-45 DAP (short-term priming), followed by mid-season water stress at 55 to 65 DAP. An automated physiological phenotyping platform was used to control irrigation and continuously monitor, soil water content, whole-plant transpiration and water use. Single-leaf measurements of net CO2 assimilation, stomatal conductance, and transpiration were taken periodically. Plant biomass and biomass partitioning were also determined. Results indicated that primed plants grown under water deficit exhibited either reduced (acclimated) or intensified (sensitized) physiological stress responses upon recurrent water stress. Timing and duration of the priming period played a key role in modulating plant phenotypic plasticity, which varied by genotype, suggesting that priming could be in part genetically controlled.

Peanut cultivar response to residual soil test potassium in North Mississippi

AbstractThe average U.S. peanut (Arachis hypogaea L.) yield has increased by approximately 25% with the adoption of peanut cultivar ‘Georgia‐06G’. Since this adoption, many new high yielding runner cultivars with similar yield potential have been released. However, current nutrient recommendations are based on soil tests that were developed prior to the release of Georgia‐06G. Particularly for potassium, current soil test potassium (STK) critical values were established on soil textures with relatively low cation exchange capacity (CEC) but were not validated on soil textures with high CEC. This study aimed to evaluate the growth and yield response of five recently released peanut cultivars to four STK levels ranging from very low to medium based on Mississippi State University Extension soil testing recommendations. The STK classification levels were also based on two soil series categorized with high CEC—Leeper (∼38.4 meq 100 g−1) and Marietta (∼15.9 meq 100 g−1) soil series. Cultivars Georgia‐06G, ‘Georgia‐16HO’, ‘Georgia‐18RU’, FloRun ‘331’, and ‘AU‐NPL‐17’ were evaluated in this study. No STK × variety interaction occurred, indicating similar K requirements across all varieties evaluated. However, a positive pod yield response occurred in both soil types when the average STK increased from 128 to 167 lbs ac−1 for all cultivars and site years. Critical STK values on both soils were greater than many current Extension recommendations, and the critical STK value of Leeper is greater than the Marietta soil series, likely due to the higher CEC value. These results demonstrate the need to adjust peanut STK sufficiency levels based on soil CEC. Further evaluation of modern peanut cultivar productivity response to STK sufficiency levels is needed for soils with moderate CEC.

Relics of interspecific hybridization retained in the genome of a drought-adapted peanut cultivar.

Peanut (Arachis hypogaea L.) is a globally important oil and food crop frequently grown in arid, semi-arid, or dryland environments. Improving drought tolerance is a key goal for peanut crop improvement efforts. Here we present the genome assembly and gene model annotation for 'Line8', a peanut genotype bred from drought tolerant cultivars. Our assembly and annotation are the most contiguous and complete peanut genome resources currently available. The high contiguity of the Line8 assembly allowed us to explore structural variation both between peanut genotypes and subgenomes. We detect several large inversions between Line8 and other peanut genome assemblies, and there is a trend for the inversions between more genetically diverged genotypes to have higher gene content. We also relate patterns of subgenome exchange to structural variation between Line8 homeologous chromosomes. Unexpectedly, we discover that Line8 harbors an introgression from A.cardenasii, a diploid peanut relative and important donor of disease resistance alleles to peanut breeding populations. The fully resolved sequences of both haplotypes in this introgression provide the first in situ characterization of A.cardenasii candidate alleles that can be leveraged for future targeted improvement efforts. The completeness of our genome will support peanut biotechnology and broader research into the evolution of hybridization and polyploidy.

Impacts of Soil Compaction and Phosphorus Levels on the Dynamics of Phosphate-Solubilizing and Nitrogen-Fixing Bacteria in the Peanut Rhizosphere

Soil properties, including soil compaction and the nutrient content, influence the composition and functions of rhizosphere microbial communities. There is limited information on how soil compaction and phosphorus application affect phosphate-solubilizing (PSB) and nitrogen-fixing bacteria (NFB). This study aimed to examine the responses of PSB and NFB in the rhizosphere of peanut (Arachis hypogaea L.) plants under varying soil compaction and phosphorus application levels. To address this, pot experiments were conducted to assess the composition and assembly processes of rhizosphere PSB and NFB in peanut cultivar Hua Yu 22 under two soil compaction levels (T1, 1.25 g/cm3 compaction, and T2, 1.00 g/cm3 compaction) and two phosphorus (P) levels (P0, no P applied, and P1, 1.2 mM P/kg soil applied). The results showed that PSB community shifts were closely correlated with the content of soil available phosphorus, soil acid phosphatase activity, soil nitrogenase activity, and soil compaction. Additionally, the content of soil available phosphorus and soil compaction were correlated with changes in operational taxonomic units of NFB. A network analysis revealed that the complexities of PSB were significantly higher than those of NFB. A stronger negative relationship was identified among NFB communities. The assembly of PSB communities was primarily driven by drift processes, whereas NFB communities were influenced by a combination of homogenizing selection and drift. Both PSB and NFB community compositions were significantly affected by phosphorus limitations and soil compaction. These findings enhance our understanding of the impacts of soil compaction and phosphorus application on PSB and NFB communities, with implications for optimizing peanut crop production. Our results will provide reference for crop cultivation in compacted and low-phosphorus soils. The important phosphate-solubilizing and nitrogen-fixing bacteria screened in the interaction network in this study will become candidate microbial agents for alleviating soil compaction and low phosphorus levels.

Agronomic Behavior of Peanut (Arachis hypogaea L.) Cultivars under Three Planting Densities in the Northeast of Peru

Factors such as the selection of cultivars and the planted density affect the development and yield of peanuts (Arachis hypogaea L.). This study’s objective was to evaluate peanut cultivars’ agronomic behavior under three planting densities in the northeast of Peru. The design used was randomized complete blocks (DBCAs) with a bifactorial arrangement 4A × 3B (factor A, peanut cultivars; factor B, planting densities), forming 12 treatments with three replications per block. The results revealed that T3 (Huayabamba cultivar + density of 30 × 50 cm) stood out, presenting the most favorable means in the number of pods (16 pods), number of seeds per pod (five seeds), height at 90 days (22.7 cm), and yield (1850 kg/ha). Empty pods did not show significant differences between treatments. T8 (Chivita cultivar + density of 20 × 50 cm) indicated the highest number of branches (six branches); in the weight of 100 seeds, the Rojo Tarapoto cultivar was the most encouraging, adapting optimally to the three densities. In addition, T7 (chivita cultivar + density of 10 × 50 cm) showed the shortest days at flowering and harvest, with 64 and 134 days. The study showed that T3 was the most efficient in pod and seed production, making it crucial to optimizing peanut yield.

Mitigating heat-induced yield loss in peanut: Insights into 24-epibrassinolide-mediated improvement in antioxidant capacity, photosynthesis, and kernel weight

Context or problemAs global temperatures steadily increase, the frequent occurrence of extreme high-temperature events has significantly hampered peanut (Arachis hypogaea L.) production in low-latitude regions. Objective or research questionPreviously, 24-epibrassinolide (EBR) was identified as a substance capable of mitigating abiotic stress damage in plants. However, it remains unclear whether and by what mechanisms EBR can diminish the yield loss caused by heat stress in peanuts. MethodsDuring the flowering phase, two distinct peanut cultivars, Qinghua7 (heat-resistant type) and Shanhua101 (heat-sensitive type) were exposed to a 10-day heat stress treatment (+4.2 ℃). EBR or water was sprayed on the 1st, 3rd, and 5th days of heating, and water-sprayed natural peanuts was used as control, to assess the effect of EBR on antioxidant capacity, photosynthetic performance, and yield in heat-stressed peanuts. ResultsEBR application increased activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase in heat-stressed peanut leaves. Simultaneously, EBR decreased hydrogen peroxide and superoxide anion production, along with a reduction in malondialdehyde content. Additionally, EBR notably alleviated the oxidation damage to chloroplast membranes and grana lamella under heat stress. Thus, an increase in maximum photochemical efficiency, comprehensive performance index, rubisco activity, net photosynthetic rate, and biomass accumulation was observed in heat-stress peanuts. Synergistic enhancement provided by EBR on antioxidant capacity and photosynthetic performance resulted in improved plant growth, kernel weight, and effective pods per plant, led to a reduction in yield loss for heat-stressed cultivars Qinghua7 and Shanhua101 by 26.92 % and 55.18 %, respectively. ConclusionsThe application of EBR enhanced the antioxidant capacity of peanut leaves. This, in turn, mitigated oxidative damage to chloroplast membranes, resulting in improved photosynthetic performance. Ultimately, this intervention led to a reduction in yield loss for heat-stressed peanuts, achieved through an increase in kernel weight. Implications or significanceThe foliar spraying of EBR holds significant promise in crop production, offering a broad application prospect. This practice is beneficial for enhancing the heat resistance of peanuts and potentially other field crops, equipping them to better withstand the increasingly severe climate challenges anticipated in the future.

Performance Evaluation of Three Peanut Cultivars Grown under Elevated CO2 Concentrations

This study explored the performance and physiological responses of three commercially used peanut cultivars in Australian farming systems under ambient and elevated CO2 conditions, aiming to identify the most suitable genotype for dual-purpose (grain and graze) cropping experiments. The experiment utilized an open-top chamber (OTC) facility to regulate CO2 concentrations. The elevated CO2 (EC) treatment targeted approximately 650 ± 50 µmol mol−1, while both ambient CO2 (AC) and control plots operated at a concentration of approximately 400 µmol mol−1. Notably, control plots without chambers served as a reference for current CO2 and environmental conditions. In contrast, despite having the same ambient CO2 concentration, AC plots were enclosed in chambers, allowing for plant growth comparisons with EC plots with the same environmental conditions aside from CO2 levels. The analyses revealed significant effects of CO2 enrichment on peanut plants. In particular, the EC treatment led to enhanced photosynthetic rates (20% in Kairi, 31% in Holt, and 19% in Alloway), alongside reduced stomatal conductance (−55% in Kairi, −32% in Holt, and −40% in Alloway), transpiration, and increased water use efficiency compared to AC conditions. Elevated CO2 levels positively influenced pod yields in Kairi (+41%) and Alloway (+36%). However, CO2 enrichment did not significantly alter the protein content, total phenolic content, cupric-reducing antioxidant capacity, and ferric-reducing antioxidant power of peanut plant material. Furthermore, no significant differences were observed in the phytochemical composition among the three cultivars under ambient or elevated CO2 conditions. On the other hand, analysis of the fibre structure conducted on peanut stover harvested at plant maturity suggested potential declines in feedstock quality. Based on the findings of this research, further investigations and testing, including simulated grazing trials, will be carried out to identify a single breed line suitable for dual-purpose management under future elevated CO2 conditions.

Soil fungal community structure and function response to rhizoma perennial peanut cultivars

BackgroundCrop-associated microorganisms play a crucial role in soil nutrient cycling, and crop growth, and health. Fine-scale patterns in soil microbial community diversity and composition are commonly regulated by plant species or genotype. Despite extensive reports in different crop or its cultivar effects on the microbial community, it is uncertain how rhizoma peanut (RP, Arachis glabrata Benth.), a perennial warm-season legume forage that is well-adapted in the southern USA, affects soil microbial community across different cultivars.ResultsThis study explored the influence of seven different RP cultivars on the taxonomic composition, diversity, and functional groups of soil fungal communities through a field trial in Marianna, Florida, Southern USA, using next-generation sequencing technique. Our results showed that the taxonomic diversity and composition of the fungal community differed significantly across RP cultivars. Alpha diversity (Shannon, Simpson, and Pielou’s evenness) was significantly higher in Ecoturf but lower in UF_Peace and Florigraze compared to other cultivars (p < 0.001). Phylogenetic diversity (Faith’s PD) was lowest in Latitude compared to other cultivars (p < 0.0001). The dominant phyla were Ascomycota (13.34%), Mortierellomycota (3.82%), and Basidiomycota (2.99%), which were significantly greater in Florigraze, UF_Peace, and Ecoturf, respectively. The relative abundance of Neocosmospora was markedly high (21.45%) in UF_Tito and showed large variations across cultivars. The relative abundance of the dominant genera was significantly greater in Arbrook than in other cultivars. There were also significant differences in the co-occurrence network, showing different keystone taxa and more positive correlations than the negative correlations across cultivars. FUNGuild analysis showed that the relative abundance of functional guilds including pathogenic, saprotrophic, endophytic, mycorrhizal and parasitic fungi significantly differed among cultivars. Ecoturf had the greatest relative abundance of mycorrhizal fungal group (5.10 ± 0.44), whereas UF_Peace had the greatest relative abundance of endophytic (4.52 ± 0.56) and parasitic fungi (1.67 ± 0.30) compared to other cultivars.ConclusionsOur findings provide evidence of crop cultivar’s effect in shaping fine-scale fungal community patterns in legume-based forage systems.Graphical abstract

Seed treatment with Stimulate® improves the initial development of peanut plants

Seed treatment with biostimulants may be an option to improve the emergence and initial growth of peanut plants. A pot experiment was conducted to evaluate the effect of using doses of Stimulate® in seed treatment on the initial growth of plants of two peanut cultivars grown in a sandy Cerrado soil. The treatments were arranged in a randomized block design in a 2 × 4 factorial scheme: two peanut cultivars [IAC Tatu ST (upright growth habit) and Runner IAC 886 (prostrate growth habit)] and four doses of Stimulate® (0; 10; 20; and 30 mL kg-1 of seeds) applied to seed treatment, with three replications. At 21 days after sowing, plant height (PH), main stem diameter (SD), number of lateral branches (NLB), and main root length (RL) were evaluated. Our results showed that peanut cultivars with different growth habits (erect and prostrate) have different responses to the application of Stimulate® doses on plant development, with the IAC Tatu ST cultivar being more responsive to the application of biostimulant. The application of 25 to 30 mL kg–1 of Stimulate® via seed treatment improved initial development of peanut plants grown in sandy soil of the Cerrado Sul-Mato-Grossense under controlled greenhouse conditions.

Response of selected peanut commercial cultivars to leaf spot diseases as influenced by fungicide inputs

Early leaf spot (caused by Passalora arachidicola) and late leaf spot (caused by Nothopassalora personata) are the most widespread, damaging foliar diseases of peanuts in the southeastern United States. When left nontreated, both diseases can prematurely defoliate peanuts and reduce peanut yields by up to 70%. Leaf spot diseases are primarily managed through a combination of fungicide applications and cultivar selection. In this study, six field experiments were conducted from 2021 to 2022 in Brewton, Headland, and Tallassee, Alabama, to evaluate the response of ten selected commercial peanut cultivars to various levels of leaf spot pressure as influenced by low- and high-input fungicide programs when compared to nontreated controls. The low input fungicide program included seven applications of chlorothalonil, whereas the high input fungicide program comprised of fluxapyroxad, pyraclostrobin, mefentrifluconazole, flutolanil, bixafen, flutriafol, tebuconazole, and/or chlorothalonil. Effects on leaf spot and pod yields were assessed. Leaf spot severity was higher for TUFRunner™ ‘297’, Georgia-16HO, and FloRun ‘331’, but was lower for AU-NPL 17, Georgia-06G, Georgia-12Y, and Georgia-14N. In terms of yield, leaf spot tolerant varieties showcased superior performance in high disease pressure, whereas susceptible varieties excelled in low disease pressure. Fungicides significantly enhanced the performance of susceptible cultivars under high leaf spot pressure, with marginal impact in low leaf spot pressure. These results highlight the importance of selecting cultivars and fungicide spray programs based on disease pressure to maximize profits.

Root systems of peanut cultivars respond differently to soil P availability to improve P uptake

AbstractBackgroundPeanut (Arachis hypogaea L.) is regarded as a crop with high nutrient use efficiency, but there may be differences between cultivars. Furthermore, there is little information on the strategy of peanut cultivars to adapt to soil P availability and to what extent they explore non‐labile P pools.AimsOur objective was to evaluate growth, root morphology, enzymatic activity in the rhizosphere, and P uptake of peanut cultivars grown under different soil P status.MethodsThe study was conducted in a greenhouse in 6‐L pots. Soils with low P (without fertilization) and high P content (with fertilization) and seven peanut cultivars of different origins, different maturation groups, and release years were investigated. Peanut shoot yield, phosphorus uptake, root growth, soil P fractions as well as phosphatase activity in the rhizosphere soil were determined.ResultsIn P‐deficient soil, a higher dry matter yield was associated with longer root hairs and root length, which resulted in decreased soil non‐labile P was observed mainly with cultivars developed in Argentina (ARG‐medium‐old and ARG‐medium‐new) and the late maturity Brazilian cultivar (BR I‐late new). These cultivars adapted well to P deficiency and were less dependent on labile P. New Brazilian early and medium maturity cultivars developed less, shorter root hairs, and showed low acid phosphatase activity in the rhizosphere under P deficiency, resulting in lower P uptake and dry matter yield. Under high P availability, new Brazilian cultivars of medium and late maturity showed the highest dry matter yield (9.0 and 9.8 g plant−1, respectively) and longest roots, around 120 m plant−1. High P availability decreased root hairs in all cultivars.ConclusionOverall, the adaptation of peanut cultivars to P‐deficient soils was lower for the new mid‐ and early‐maturing Brazilian cultivars compared with the Argentinian and old or late‐maturing Brazilian cultivars. The main strategies of P‐efficient cultivars under low P availability are to increase root length, root hair length, and root hair density.

Induction of new allelic variant of AhFAD2B gene in peanut cultivar, GG20 through CRISPR/Cas9-mediated mutagenesis

Induction of new allelic variant of AhFAD2B gene in peanut cultivar, GG20 through CRISPR/Cas9-mediated mutagenesis

Effect of plant density on total oil quality and fatty acid compositions in peanut (Arachis hypogaea L.) cultivars

Research in the Eastern Mediterranean Transition Region of Türkiye has demonstrated that plant density impact yield of peanut (Arachis hypogaea L.) cultivars differentially. It is suspected that interactions of plant density and cultivar could also impact oil quality and fatty acid composition when grown in this region. This topic has not been addressed in the country; therefore, the objective of this research was to determine if plant density can affect those variables. The study was conducted in 2020 and 2021 in the zone of Osmaniye to determine total oil content of kernels, and contents of oleic acid, palmitic acid, arachidonic acid, linoleic acid, stearic acid, and lignoceric acid, as well as iodine value and oleic/linoleic ratio for the cultivars Halisbey, Rigel, Aysehanım, NC 7, and Masal. Plant response was in most instances different regardless of plant populations made up of a single row planting pattern with rows spaced 70 cm apart (95.000 plants ha-1) compared with a twin row planting pattern with rows spaced 20 cm apart on 90 cm centers with an intra-row distance of 15 cm (148.000 plants ha-1). It is concluded that no differences in oil quality and fatty acid composition were noted when comparing cultivars established at various combinations of planting pattern and plant population, but there were notable differences among the cultivars.

Melatonin seed priming improves early establishment and water stress tolerance of peanut

Water stress is a major cause of yield loss in peanut cultivation. Melatonin seed priming has been used to enhance stress tolerance in several crops, but not in peanut. We investigated the impact of seed priming with melatonin on the growth, development, and drought tolerance of two peanut cultivars, TUFRunner™ ‘511’, a drought tolerant cultivar, and New Mexico Valencia A, a drought sensitive cultivar. Peanut seed priming tests using variable rates of melatonin (0–200 μM), indicated that 50 μM of melatonin resulted in more uniform seed germination and improved seedling growth in both cultivars under non stress conditions. Seed priming with melatonin also promoted vegetative growth, as evidenced by higher whole-plant transpiration, net CO2 assimilation, and root water uptake under both well-watered and water stress conditions in both cultivars. Higher antioxidant activity and protective osmolyte accumulation, lower reactive oxygen species accumulation and membrane damage were observed in primed compared with non-primed plants. Seed priming with melatonin induced a growth promoting effect that was more evident under well-watered conditions for TUFRunnner™ ‘511’, whereas for New Mexico Valencia A, major differences in physiological responses were observed under water stress conditions. New Mexico Valencia A primed plants exhibited a more sensitized stress response, with faster down-regulation of photosynthesis and transpiration compared with non-primed plants. The results demonstrate that melatonin seed priming has significant potential to improve early establishment and promote growth of peanut under optimal conditions, while also improve stress tolerance during water stress.

Non-destructive SPE-UPLC-based Quantification of Aflatoxins and Stilbenoid Phytoalexins in Single Peanut (Arachis spp.) Seeds.

Aflatoxins are highly carcinogenic secondary metabolites of some fungal species, particularly Aspergillus flavus. Aflatoxins often contaminate economically important agricultural commodities, including peanuts, posing a high risk to human and animal health. Due to the narrow genetic base, peanut cultivars demonstrate limited resistance to fungal pathogens. Therefore, numerous wild peanut species with tolerance to Aspergillus have received substantial consideration by scientists as sources of disease resistance. Exploring plant germplasm for resistance to aflatoxins is difficult since aflatoxin accumulation does not follow a normal distribution, which dictates the need for the analyses of thousands of single peanut seeds. Sufficiently hydrated peanut (Arachis spp.) seeds, when infected by Aspergillus species, are capable of producing biologically active stilbenes(stilbenoids) that are considered defensive phytoalexins. Peanut stilbenes inhibit fungal development and aflatoxin production. Therefore, it is crucial to analyze the same seeds for peanut stilbenoids to explain the nature of seed resistance/susceptibility to the Aspergillus invasion. None of the published methods offer single-seed analyses for aflatoxins and/or stilbene phytoalexins. We attempted to fulfill the demand for such a method that is environment-friendly, uses inexpensive consumables, and is sensitive and selective. In addition, the method is non-destructive since it uses only half of the seed and leaves the other half containing the embryonic axis intact. Such a technique allows germination and growth of the peanut plant to full maturity from the same seed used for the aflatoxin and stilbenoid analysis. The integrated part of this method, the manual challenging of the seeds with Aspergillus, is a limiting step that requires more time and labor compared to other steps in the method. The method has been used for the exploration of wild Arachis germplasm to identify species resistant to Aspergillus and to determine and characterize novel sources of genetic resistance to this fungal pathogen.

Registration of ‘Georgia‐23RKN’ peanut

Registration of ‘Georgia‐23RKN’ peanut

Registration of ‘TifJumbo’ peanut

Abstract‘TifJumbo’ (Reg. no. CV‐157, PI 701814) is a virginia‐type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) cultivar released by the USDA–ARS and the Georgia Agricultural Experiment Station in 2021. TifJumbo was developed at the University of Georgia Coastal Plain Experiment Station, Tifton, GA. Our research objective was to develop a high oleic acid, virginia market‐type cultivar that also has resistance to the peanut root‐knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] and resistance to spotted wilt caused by Tomato spotted wilt tospovirus (TSWV). Breeding populations were developed by hybridizing C1805‐2‐9‐16 × N08082olJCT. C1805‐2‐9‐16 is a breeding line selected from the cross of Tifguard × ‘Florida‐07’. N08082olJCT is a ‘Bailey’‐derived, high‐oleic breeding line. Marker assisted selection was used in the development of TifJumbo to select for nematode resistance and the high oleic to linoleic (O/L) characteristic. TifJumbo has a high level of resistance to both the peanut root‐knot nematode and TSWV and has a high O/L ratio. When tested in fields without nematode pressure, TifJumbo exhibited yields that were at least similar to other currently grown peanut cultivars. When tested in fields with nematode pressure, TifJumbo exhibited significantly higher yields in comparison to Bailey, a widely grown, nematode‐susceptible, virginia‐type cultivar. Grade variables for TifJumbo were similar to other common virginia‐type peanut cultivars. Seed size and size distribution were similar to other virginia‐type cultivars.