The publication focuses on nitrogen (N) requirements for corn production using best management practices (BMPs) in Florida. The intended audience is corn producers, agricultural consultants, Extension agents, Extension specialists, and researchers. The aim is to provide and recommend BMPs that comply with statewide BMP guidelines, maximizing the yield and economic return while minimizing environmental N losses. The guidelines present results from multi-year, multi-site, field-based research conducted by the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS). The small plot research was conducted at the UF/IFAS North Florida Research and Education Center, Suwannee Valley, Live Oak, Florida (NFREC-SV). The publication includes a recommendation in terms of N required per bushel of productivity.

This publication discusses the current management and cultural practices for peanut production. This article is intended to share the latest information about peanut production and management with farmers, crop consultants, and Extension agents. Written by S. S. Sidhu, D. L. Wright, B. Tillman, N. Dufault, I. M. Small, I. L. Esquivel, Z. Grabau, H. Singh, E. Matcham, E. A. Borgato, J. Capasso, S. Kumar, and E. Carter, and published by the UF/IFAS Department of Agronomy, January 2026.

Safflower is a drought-resilient crop with seed-oil rich in unsaturated linoleic and oleic acids. However, the low oil content has deterred its adoption as a major oilseed. We profiled a global collection of 1497 safflower accessions from twelve regional gene pools for their seed-oil content and fatty-acid composition. Oil content was estimated using the non-destructive Near-Infrared Reflectance Spectroscopy method based on a newly calibrated equation. Our findings highlight significant variability in the global reference collection for oil content, which ranged from 11.24 % to 59.16 %. The robustness of our calibrated equation was demonstrated by the strong correlation between datasets from two years (0.68 %). Furthermore, germplasm evaluation for fatty acid composition using gas chromatography revealed substantial diversity in linoleic (8.22-87.27 %) and oleic acid (6.98-85.84 %) content of safflower seeds. Collectively, accessions from USA and Indian subcontinent gene pools exhibited greatest variability in seed oil traits. In total, we identified eight accessions with very high oil content (>50 %), four accessions with high oil content (>40 %) coupled with desirable oleic acid (>75 %). The present work will aid safflower breeding programs.

Multiple federal and state agencies provide assistance to qualified agricultural producers following a natural disaster, such as a hurricane. However, the programs change over time, and many producers are not aware of the programs available. The purpose of this publication is to list and briefly describe disaster assistance resources available to agricultural producers in Florida after Hurricane Idalia. To the extent that some information remains the same, this publication could provide guidance to Extension agents, nongovernmental organizations, and producers impacted by future hurricanes. The information was compiled from websites, government documents, and discussions with government agency representatives following Hurricane Idalia.

The combination of subsoil compaction and injudicious usage of nitrogenous fertilizers are key factors that may lower crop yields, especially in soils with a shallow hardpan. Therefore, the objective of this study was to determine the effects of tillage and N application on carinata productivity in rainfed conditions. A 3-year field study was conducted at the North Florida Research and Education Center, Quincy, FL, USA. Treatments were four rates of N (0, 45, 90, and 135 kg N ha(-1)) and three tillage methods (disking, chiseling, and no-tillage). Maximum cone index measurements for no-tillage occurred at 15 cm but at 20 cm soil depth for both chisel and disk tillage. A hardpan at 15 cm restricted taproot growth but promoted lateral root growth. Subsoiling and N application improved carinata growth relative to no-tillage. Seed yield response to N application rate depended on the tillage method. The agronomic maximum seed yield occurred at 134, 128, and 125 kg N ha(-1) for chisel, disk, and no-tilled systems. Nitrogen agronomic efficiency was greatest at 45 kg N ha(-1) for the chisel method and 95 kg N ha(-1) for disk and no-tillage. Tillage has a greater potential to increase yields even at relatively low N levels. When tilled, carinata produces 8%-17% greater seed yield at 45 kg N ha(-1) than no-tilled carinata grown with 135 kg N ha(-1). These results indicate that tilling the subsoil and applying 90-135 kg N ha(-1) are required for carinata production in soils with a hardpan.

Tomato spotted wilt virus (TSWV) has the potential to cause severe yield losses in peanut (Arachis hypogaea L.), an important annual legume grown around the world. The most effective approach to manage the disease caused by TSWV is to grow disease resistant peanut varieties. One of the key challenges to breeding for disease resistance is to develop an accurate, reproducible and efficient disease assessment method. Accurate field-based assessment of disease incidence and severity is technically challenging and time-consuming. To address this challenge, a field-based, high-throughput assessment tool was developed to quantify the spatial distribution of disease symptoms over experimental peanut plots using a Real Time Kinematic Global Positioning System (RTK-GPS), consumer-grade cameras, a microcontroller, and an open-source machine learning software. A field experiment was designed to establish a range of disease incidence and severity scenarios. This field experiment was imaged for two seasons to develop and validate the tool. Using transfer learning, an existing Convolutional Neural Network (CNN) was trained from supervised training imagery to classify and quantify areas within the plot-level imagery as, symptomatic, asymptomatic, or ground. Multiple images were assessed by the machine learning model and georeferenced to individual experimental plots using RTK-GPS data. The CNN model trained to detect the symptom, “stunting and mottling”, was evaluated using Receiver Operating Characteristic (ROC) curve analysis and yielded an Area Under the Curve (AUC) of 0.97, sensitivity of 0.77, and specificity of 0.98 on the test set. Results from the disease assessment tool were compared with results from visual disease assessments, conducted by a trained plant pathologist. Field plot level means from CNN-based assessment of stunting and mottling correlated with plot level means from visual assessment of severity (r = 0.78; P < 0.0001). To further validate the CNN-based method, the TSWV field experiment was analyzed using linear mixed models with both visual severity and CNN-based severity assessments used as responses. Both models (visual or CNN-based assessment) identified the same main effects as being significant and post hoc analysis resulted in the same separation of varieties for their severity of TSWV symptoms. The results of this study demonstrate the successful application of this tool for high-throughput disease severity assessment in peanut under field conditions.

Brassica carinata is a non‐food, low‐carbon, none‐to‐low indirect land‐use change impact oilseed feedstock grown for sustainable biofuels, bioproducts, and high protein seed meal. Understanding carinata growth and development is critical to the development of best management practices for maximum productivity and profitability of double‐cropped farming systems. Field experiments were conducted during 2017–2018 (Year 1) and 2018–2019 (Year 2) winter–spring growing seasons in Quincy, Florida, to quantify the total aboveground dry matter accumulation (TDM), allocation, growth, nutrient uptake, and seed quality. The two carinata cultivars Avanza 641 and AX17012 accumulated 10826 and 9343 kg TDM ha −1 in Year 1 and 9655 and 10,642 kg TDM ha −1 in Year 2, respectively, at harvest maturity. The proportion of DM in the vegetative parts such as leaves and stems decreased, and the DM in reproductive structures such as silique walls and seeds increased with maturity. Seed yield (SY) was similar between cultivars but differed between years with Year 1 (2732 kg ha −1 ), producing 29% greater SY than Year 2 (1929 kg ha −1 ). Carinata primary stem has 17–20 leaf nodes, with 75%–88% of the axillary meristems producing primary and secondary branches. Crop growth rate (CGR) increased from vegetative to pod development for both cultivars in Year 1, while in Year 2, AX17012 and Avanza 641 attained maximum CGR at the pod development and bolting/flowering stages, respectively. Maximum seasonal nutrient uptake in leaves, stems, and siliques generally occurred in the early, mid, and late season, respectively, in both years. Seed weight, oil, monounsaturated fatty acids, C18:3, C20:1, and C22:1 concentrations increased with plant age, whereas protein, glucosinolate, polyunsaturated fatty acids, saturated fatty acids, C18:1, and C18:2 concentrations decreased with plant maturity. These results can be used for crop modeling to predict growth, development, and yield and aid in developing in‐season decision support tools.

The environmental consequences of using nonrenewable fossil fuels have motivated a global quest for sustainable alternatives from renewable sources. Carinata has been developed as a low carbon intensity, non‐food oilseed biomolecular platform to produce advanced drop‐in renewable fuels, meal, and co‐products. The crop is widely adaptable to grow in the humid subtropical and humid continental climatic regions of Asia, Africa, North America, South America, Europe, and Australia as a spring or winter crop. Carinata is heat tolerant, resistant to diseases and seed shattering with lower water‐use requirements than other oilseed brassicas. Adopting carinata in double‐cropping systems would require continuing research to integrate crop biology with agronomy, to understand growth and development and its interaction with agricultural inputs and management. Site‐specific best management agronomic practices and crop improvement research to develop frost‐tolerant, early‐maturing, nutrient use‐efficient, and high yielding varieties with desirable oil content and fatty acid profile will enhance the crop's adaptability and economic viability. The exploitation of intra‐ and interspecific and intra‐ and intergeneric diversity will further enhance carinata productivity and resistance to biotic and abiotic stresses. This review attempts to present a comprehensive description of carinata's biology, beginning with its origin and current state of distribution, availability of genetic and genomic resources, and a discussion of its morphology, phenology, and reproduction. A detailed analysis of the agronomy of the crop, including planting and germination and management practices, is presented in the context of crop growth and development. This will facilitate global adoption, sustainable production, and commercialization of carinata as a dedicated biofuel oilseed crop in diverse cropping systems and growing regions of the world, including the Southeast United States.

Brassica carinata (carinata) has emerged as a potential biofuel source due to its high erucic acid content, making it desirable for various industrial applications. Nitrogen (N) and sulfur (S) are required as primary sources of nutrition for growth and development in different oilseed crops and their utilization is interdependent. The purpose of the study was to analyze the interactive effect of N and S nutrition on the growth and other physiological activities of carinata and B. napus (napus). Four treatments, i.e., optimum NS (+N+S, 100% N and 100% S); N limited (−N+S, 0% N, 100% S); S limited (+N−S, 100% N, 0% S), and NS limited (−N−S, 0% N and 0% S) of N and S in full-strength Hoagland solution were imposed in the current study. Effect of different NS treatments was observed on vegetative traits such as number of primary and secondary branches, total leaf area, total biomass production and allocation, and physiological traits such as production of photosynthetic pigments, net photosynthesis, electron transport, and other aspects for both carinata and napus. The traits of stem elongation, number of nodes, node addition rate, internode length, number of primary and secondary branches were 60%, 36%, 50%, 35%, 56%, and 83% lower, respectively, in napus in comparison to carinata. Different NS treatments also positively influenced the production of photosynthetic pigments such as chlorophyll (Chl) a and b and carotenoids in carinata and napus. The concentration of Chla was 11% higher in napus in comparison to carinata. The rate of net photosynthesis, electron transport, and fluorescence was 12%, 8%, and 5% higher based on overall value, respectively, in napus compared to carinata. On the other hand, the overall value for stomatal conductance decreased by 5% in napus when compared to carinata. Different growth-related traits such as vegetative (plant height, node number, internode length, leaf area, number of primary and secondary branches), reproductive (pod number, pod length, seeds per pod), and photosynthetic capacity in oilseed brassicas are correlated with the final seed and oil yield and chemical composition which are of economic importance for the adoption of the crop. Thus, the analysis of these traits will help to determine the effect of NS interaction on crop productivity of carinata and napus.

Genetic diversity provides the foundation for plant breeding and genetic research. Over 3000 rice genomes were recently sequenced as part of the 3K Rice Genome (3KRG) Project. We added four additional Indian rice accessions to create a panel of 3004 accessions. However, such a large collection of germplasm is difficult to preserve and evaluate. The construction of core and mini-core collections is an efficient method for the management of genetic resources. In this study, we developed a mini-core comprising 520 accessions that captured most of the SNPs and represented all of the phenotypes and geographic regions from the original panel. The mini-core was validated using different statistical analyses and contained representatives from all major rice groups, including japonica, indica, aus/boro, and aromatic/basmati. Genome-wide association analyses of the mini-core panel efficiently reproduced the marker-trait associations identified in the original panel. Haplotype analysis validated the utility of the mini-core panel. In the current era with many ongoing large-scale sequencing projects, such a strategy for mini- core design should be useful in many crops. The rice mini-core collection developed in this study would be valuable for agronomic trait evaluation and useful for rice improvement via marker-assisted molecular breeding.

Brassica carinata A. Braun, grown as a winter crop on underutilized agricultural land in the southeast United States (SE US), may provide a new rotation alternative and augment income for producers. Widespread adoption of Brassica carinata as a winter crop in the SE US requires varieties with cold tolerance, acceptable and stable seed yield, oil content, protein content so that the crop will be complementary with the normal cultivation of summer crops such as cotton (Gossypium hirsutum L.), corn (Zea mays L.), soybean (Glycine max L. Merr), sorghum (Sorghum bicolor L. Moench) and peanut (Arachis hypogaea L.). The objective of this study was to evaluate the performance of 11 Brassica carinata genotypes for agronomically important traits including seed yield, oil and protein content, oil quality, days to bolting, flowering and maturity at three locations during two growing seasons (2015-2017) as a winter crop in the SE US. Interactions between genotype and environment played a crucial role in overall agronomic performance. This study provides key information on the effect of environmental conditions, such as precipitation and temperature on the agronomic performance of carinata along with generation of information related to region-specific requirements for the crop in the SE US. Days to maturity ranged from 154 to 165 days. The average yield of the 11 genotypes tested ranged from 2814 kg/ha to 3401 kg/ha, which were improved from earlier studies, demonstrating gain due to regional selection and breeding efforts. Total oil content ranged from 42.0 % to 52.4 %, while the erucic acid (C22:1) content ranged from 40.7 % to 42.9 % on a whole seed basis. Based on these results, specific genotypes with consistently high seed yield, oil, erucic acid and protein content with shorter life cycle irrespective of location or year were identified. Brassica carinata has potential as a viable bioenergy winter crop to be integrated into the cropping systems in the SE US and other regions of the world.

Carthamus tinctorius L. (safflower) is an important oilseed crop producing seed oil rich in unsaturated fatty acids. Scarcity of identified marker-trait associations is a major limitation toward development of successful marker-assisted breeding programs in safflower. In the present study, a safflower panel (CartAP) comprising 124 accessions derived from two core collections was assayed for its suitability for association mapping. Genotyping of CartAP using microsatellite markers revealed significant genetic diversity indicated by Shannon information index (H = 0.7537) and Nei's expected heterozygosity (I = 0.4432). In Principal Coordinate Analysis, the CartAP accessions were distributed homogeneously in all quadrants indicating their diverse nature. Distance-based Neighbor Joining analysis did not delineate the CartAP accessions in consonance with their geographical origin. Bayesian analysis of population structure of CartAP demonstrated the unstructured nature of the association panel. Kinship analysis at population (Gij ) and individual level (Fij ) revealed absence of or weak relatedness between the CartAP accessions. The above parameters established the suitability of CartAP for association mapping. We performed association mapping using phenotypic data for eight traits of agronomic value (viz., seed oil content, oleic acid, linoleic acid, plant height, number of primary branches, number of capitula per plant, 100-seed weight and days to 50% flowering) available for two growing seasons (2011-2012 and 2012-2013) through General Linear Model and Mixed Linear Model. Our study identified ninety-six significant marker-trait associations (MTAs; P < 0.05) of which, several MTAs with correlation coefficient (R2) > 10% were consistently represented in both models and in both seasons for traits viz., oil content, oleic acid content, linoleic acid content and number of primary branches. Several MTAs with high R2-values were detected either in a majority or in some environments (models and/or seasons). Many MTAs were also common between traits (viz., oleic/linoleic acid content; plant height/days to 50% flowering; number of primary branches/number of capitula per plant) that showed positive or negative correlation in their phenotypic values. The marker-trait associations identified in this study will facilitate marker-assisted breeding and identification of genetic determinants of trait variability.

Safflower (Carthamus tinctorius L.) is a dryland oilseed crop yielding high quality edible oil. Previous studies have described significant phenotypic variability in the crop and used geographical distribution and phenotypic trait values to develop core collections. However, the molecular diversity component was lacking in the earlier collections thereby limiting their utility in breeding programs. The present study evaluated the phenotypic variability for 12 agronomically important traits during two growing seasons (2011-12 and 2012-13) in a global reference collection of 531 safflower accessions, assessed earlier by our group for genetic diversity and population structure using AFLP markers. Significant phenotypic variation was observed for all the agronomic traits in the representative collection. Cluster analysis of phenotypic data grouped the accessions into five major clusters. Accessions from the Indian Subcontinent and America harbored maximal phenotypic variability with unique characters for a few traits. MANOVA analysis indicated significant interaction between genotypes and environment for both the seasons. Initially, six independent core collections (CC1-CC6) were developed using molecular marker and phenotypic data for two seasons through POWERCORE and MSTRAT. These collections captured the entire range of trait variability but failed to include complete genetic diversity represented in 19 clusters reported earlier through Bayesian analysis of population structure (BAPS). Therefore, we merged the three POWERCORE core collections (CC1-CC3) to generate a composite core collection, CartC1 and three MSTRAT core collections (CC4-CC6) to generate another composite core collection, CartC2. The mean difference percentage, variance difference percentage, variable rate of coefficient of variance percentage, coincidence rate of range percentage. Shannon's diversity index, and Nei's gene diversity for CartC1 were 11.2, 43.7, 132.4, 93.4, 0.47, and 0.306, respectively while the corresponding values for CartC2 were 9.3, 58.8, 124.6, 95.8, 0.46, and 0.301. Each composite core collection represented the complete range of phenotypic and genetic variability of the crop including 19 BAPS clusters. This is the first report describing development of core collections in safflower using molecular marker data with phenotypic values and geographical distribution. These core collections will facilitate identification of genetic determinants of trait variability and effective utilization of the prevalent diversity in crop improvement programs.

BACKGROUND:Safflower (Carthamus tinctorius L.), an Asteraceae member, yields high quality edible oil rich in unsaturated fatty acids and is resilient to dry conditions. The crop holds tremendous potential for improvement through concerted molecular breeding programs due to the availability of significant genetic and phenotypic diversity. Genomic resources that could facilitate such breeding programs remain largely underdeveloped in the crop. The present study was initiated to develop a large set of novel microsatellite markers for safflower using next generation sequencing.PRINCIPAL FINDINGS:Low throughput genome sequencing of safflower was performed using Illumina paired end technology providing ~3.5X coverage of the genome. Analysis of sequencing data allowed identification of 23,067 regions harboring perfect microsatellite loci. The safflower genome was found to be rich in dinucleotide repeats followed by tri-, tetra-, penta- and hexa-nucleotides. Primer pairs were designed for 5,716 novel microsatellite sequences with repeat length ≥ 20 bases and optimal flanking regions. A subset of 325 microsatellite loci was tested for amplification, of which 294 loci produced robust amplification. The validated primers were used for assessment of 23 safflower accessions belonging to diverse agro-climatic zones of the world leading to identification of 93 polymorphic primers (31.6%). The numbers of observed alleles at each locus ranged from two to four and mean polymorphism information content was found to be 0.3075. The polymorphic primers were tested for cross-species transferability on nine wild relatives of cultivated safflower. All primers except one showed amplification in at least two wild species while 25 primers amplified across all the nine species. The UPGMA dendrogram clustered C. tinctorius accessions and wild species separately into two major groups. The proposed progenitor species of safflower, C. oxyacantha and C. palaestinus were genetically closer to cultivated safflower and formed a distinct cluster. The cluster analysis also distinguished diploid and tetraploid wild species of safflower.CONCLUSION:Next generation sequencing of safflower genome generated a large set of microsatellite markers. The novel markers developed in this study will add to the existing repertoire of markers and can be used for diversity analysis, synteny studies, construction of linkage maps and marker-assisted selection.

Carthamus tinctorius L. (safflower) is an important oilseed crop that is cultivated in several countries. The present study investigates the genetic diversity and population structure of 531 safflower accessions from 43 countries representing all safflower growing regions of the world. Diversity analysis was performed using ten informative E co RI/M se I amplified fragment length polymorphism primer pairs that were identified by screening 150 primer combinations. The selected primer pairs generated 381 fragments of which 157 were polymorphic among the analyzed accessions. The genetic diversity indices obtained for the entire collection ( I = 0.4536, H = 0.2955) indicated high levels of molecular variability. The distance-based, neighbor-joining method classified the accessions into six clusters with internal subgroupings that were in consonance with 19 clusters obtained using Bayesian model-based BAPS analysis. Clusters obtained through STRUCTURE analysis (at K = 4) could not be correlated with their geographically diverse origins, while BAPS analysis (at K = 19) revealed geographical delineation with low admixture levels among most of the studied accessions. Accessions from Far East and Egypt clustered in distinct groups, indicating conserved nature of their gene pools. The Near East and Iran–Afghanistan regions were collectively found to harbor maximum diversity in accordance with earlier reports. Accessions from the Indian subcontinent showed substantial diversity that was previously undetected. The American accessions showed low molecular variability in contrast to earlier studies. Genetic sub-structuring within gene pools and inter-relationships between accessions belonging to different regional pools was also observed. To the best of our knowledge, this is the first comprehensive study of existing genetic variability in a large collection of safflower germplasm with a global distribution, which provides a more accurate representation of genetic structuring in the crop. This information will facilitate selection of elite genotypes for broadening the genetic base of various breeding programs in safflower.