Abstract Demand for organic fertilizers has prompted the exploration of different sources of sustainable, plant‐based alternatives for turfgrass lawns. This study evaluated defatted soybean flour as a potential plant‐based fertilizer option for high‐cut turfgrass systems such as lawns, parks, recreational facilities, and commercial landscapes when applied as a powder, drench, or spray to perennial ryegrass ( Lolium perenne L.) and tall fescue [ Schedonorus arundinaceus (Schreb.) Dumort]. The fertilizer response of soybean flour was compared to corn gluten meal (CGM) and untreated controls in greenhouse and field experiments in Wooster and Columbus, OH, and West Lafayette, IN. In a greenhouse, soybean flour was applied as a powder in a proof‐of‐concept experiment, which resulted in positive dose‐dependent turfgrass responses, with an optimal nitrogen rate between 19.5 and 29.3 kg N ha − 1 . Staged‐up proof‐of‐concept field trials in which soybean flour was drenched on turfgrass plots confirmed these greenhouse findings. Unlike CGM, which showed a gradual improvement in turfgrass quality when applied to field plots, soybean flour produced more rapid initial growth responses from 7 to 14 days post application. Following initial proof‐of‐concept experiments, soybean flour was sprayed on turfgrass plots, in which turfgrass growth and other parameters increased with soybean flour application compared to untreated controls. The results suggest that soybean flour could be a viable plant‐based fertilizer for high‐cut cool‐season lawns, offering comparable performance to CGM, with potential for broader adoption in environmentally conscious turfgrass management. Future work should focus on refining application methods and nutrient release profiles to improve practicality and consistency for industry and homeowner use.
Abstract Interest in microbial plant growth‐promoting processes, particularly biological nitrogen (N) fixation (BNF), has increased globally as a strategic alternative to mineral N fertilization. Understanding the response of root traits to diverse N sources plays a critical role in unraveling canopy dynamics and improving decision‐making in forage‐livestock systems. This study investigated how N‐supply strategies, including Azospirillum brasilense (strains Ab‐V5 and Ab‐V6; CNPSo) inoculation and symbiotic BNF via Mandobi forage peanut ( Arachis pintoi Krapov. & W.C. Greg.), affect root and canopy characteristics of Ipyporã brachiariagrass ( Urochloa (syn. Brachiaria ) interspecific hybrid BRS RB331 Ipyporã [ U. ruziziensis Germ. & Evrard × U. brizantha (Hochst. ex A. Rich.) Stapf]). Six strategies were evaluated over 2 years: a control (no N), mineral N (80 kg N ha − 1 year − 1 ), A. brasilense (Az), 80N+Az (80 kg N ha − 1 year − 1 plus A. brasilense inoculation), grass–peanut (Ipypora brachiariagrass with Mandobi forage peanut) mixture (Mix), and Mix+Az. All N‐supply strategies resulted in 61% greater net CO 2 assimilation compared to the control (33 µmol m −2 s −1 ). Mineral N, Az, 80N+Az, and Mix+Az strategies did not differ in root mass (1630 kg dry matter [DM] ha − 1 ), root total non‐structural carbohydrate (TNC) pool (168 g m −2 ), root N concentration (40.3 g kg −1 ), and herbage accumulation (8000 kg DM ha − 1 year − 1 ). Regardless of the N source, root TNC concentration (10.6 g kg −1 ), leaf proportion (26.7%), and leaf area index were similar across strategies. Our findings show that root mass, root TNC pool, and root N pool were associated with canopy response, supporting greater net CO 2 assimilation and herbage accumulation under both microbial and mineral N‐supply strategies. Under the conditions of this study, A. brasilense and grass‐legume mixtures show potential as complementary strategies to mineral N fertilization in tropical pastures.
Abstract Kentucky bluegrass ( Poa pratensis L.) is a cool‐season grass used for forage and turf with seed production occurring primarily in the Pacific Northwest region of the United States. Climate change in this region, characterized by warmer winters, threatens Kentucky bluegrass flowering and seed yield due to altered vernalization patterns. This 2‐year field study investigated the effects of gibberellic acid (GA 3 ), specifically RyzUp Smartgrass, on seed yield, biomass accumulation, and turf performance of the Kentucky bluegrass cultivar Midnight. Treatments included fall and spring applications with untreated control along with three GA 3 doses (35, 70, and 140 g/ha) under three application schedules (early, late, and early + late). Seed yield significantly increased during the first‐year fall applications, with the 35 g/ha early and late treatments improving yield by 116% and 100%, respectively. However, spring applications did not enhance seed yield, and high‐dose treatments negatively impacted yield in the second spring. Biomass accumulation significantly improved, especially with spring GA 3 applications. The highest biomass increase (144%) occurred with the 140 g/ha double spray in the first year. Instant biomass visual assessments 2 weeks post‐application indicated rapid vegetative responses to GA 3 across treatments. Additionally, spring GA 3 treatments significantly increased plant height, row spreading, and visual turf color quality. No negative impacts on seed vigor, viability, or 1000‐grain weight were observed. This study highlights GA 3 ’s potential as an agronomic tool for enhancing Kentucky bluegrass seed yield and biomass, particularly when applied during the fall at lower doses and in spring for rapid turfgrass establishment and renovation.
Abstract High‐dimensional data present major challenges in identifying key predictors of phenotypic variation, particularly when response distributions are asymmetric or heavy tailed. Traditional variable selection methods focus on the conditional mean, limiting their utility in scenarios with heterogeneity across quantiles. This study applies a Bayesian Quantile Regression model with Variable Selection (BQRVS), which extends classical quantile regression through a hierarchical Bayesian framework and provides selective shrinkage of coefficients through hierarchical priors, along with full posterior uncertainty estimation for all parameters. The BQRVS model was evaluated on two real datasets. The first involves the detection of quantitative trait loci associated with grain yield in barley, using genomic markers and quantile‐specific modeling to identify predictors associated with the lower and upper regions of the conditional yield distribution. The second case explores the relationship between hyperspectral reflectance data and grain yield for maize using field‐collected data. In both examples, the model was fitted at multiple quantiles , for probability levels θ ∈ {0.1, 0.5, 0.9} using prior distributions that favor sparsity. Results revealed quantile specific relevance of genomic markers and spectral bands, with certain predictors influencing only low or high quantiles of the response. These findings underscore the importance of moving beyond mean‐based approaches, especially in plant breeding and phenotyping contexts characterized by complex or non‐normal response behavior. The BQRVS framework provides a flexible and efficient tool for robust variable selection and prediction in genomic and spectral data analysis, offering new insights into the structure of trait variation across the distribution of interest.
Abstract Hairy vetch ( Vicia villosa Roth) and smooth vetch ( Vicia varia Host) are legume cover crops with strong winter survival and biomass productivity. Both species tend toward outcrossing but are also self‐compatible, suggesting that the species are mixed mating. This study quantified self‐pollination rates and inbreeding depression in V. villosa and V. varia within an active US breeding program using single sequence repeat markers. Self‐pollination rates were determined using parents and progeny samples in 172 half‐sib families ( n = 2370 progeny). Progeny with more than one allele varying from the maternal parent were considered the result of cross‐pollination. Parent–progeny samples were collected from early‐cycle mothers with unselected progeny seed, early‐cycle mothers with low‐selection‐intensity progeny plants, and advanced‐cycle mothers with high‐selection‐intensity progeny plants. Mean self‐pollination rate across all samples was 13.0%, with strong variation among families (0%–81%). Unselected progeny seed had low self‐pollination rates (4.8%) relative to early‐cycle progeny (27.6%) and advanced‐cycle progeny (21.6%). Species identity did not impact self‐pollination rate, but both parent growing environment and breeding germplasm source had significant but minor ( p < 0.05) effects. Self‐pollinated offspring had inbreeding depression for biomass (−48%), seed yield (−45%), plant maturity, seed dormancy, and pod dehiscence. These results confirm that these two cover crop vetch species are mixed‐mating systems. The strong skew in self‐pollination rates among families is an unexpected observation that parallels other reports from mixed‐mating species. Skewed self‐pollination rates pose a practical challenge for breeding programs and may have implications for the prevalence of mixed mating in natural systems.
Abstract Plant height is an important agronomic trait in rice and shows marked divergence between wild and cultivated germplasm. To identify loci associated with plant height variation from wild rice, we developed a BC 4 F 7 chromosome segment substitution line population of 308 lines derived from Yuanjiang common wild rice ( Oryza rufipogon ) and elite cultivar Youzhan 8 ( Oryza sativa ). Bulked segregant analysis coupled with sequencing identified a 13.6‐Mb quantitative trait loci region on chromosome 7 associated with plant height. Eight prioritized candidate genes were identified within this interval based on sequence polymorphism and functional annotation, including known regulators OsTCP21 and PROG1 . Quantitative RT‐PCR analysis of stem tissues at the jointing stage detected measurable expression for five of these genes. Four genes, OsTCP21 , OsFBL35 , OsFBA2 , and LOC_Os07g08190 , showed significant differential expression between tall and dwarf lines, whereas GID1L2 did not. The other three genes, including PROG1 , showed transcript levels too low for reliable detection. Haplotype analysis further identified coding and promoter variation in OsFBL35 , OsFBA2 , LOC_Os07g08190 , and GID1L2 , as well as promoter haplotypes in OsTCP21 . These results suggest that OsTCP21, OsFBL35 , OsFBA2 , LOC_Os07g08190 , and GID1L2 are potential candidate genes for plant height variation in this wild rice‐derived population. Functional annotation suggested that these candidates may be related to ubiquitination, hormone signaling, and growth regulation. These findings provide insight into the genetic basis of plant height variation derived from wild rice and offer candidate loci and molecular markers for rice improvement.
Abstract The North China Plain (NCP) faces severe water scarcity, threatening sustainable agriculture. Micro‐sprinkling irrigation (MSI) has been instrumental in enhancing crop yield. Nevertheless, there is a paucity of research on the impact of MSI on purple wheat ( Triticum aestivum L.). A 2‐year field experiment comparing the effects of conventional flood irrigation (CI) and MSI on purple wheat was conducted, in which grain yield and its components, dry matter (DM) and nitrogen (N) accumulation and partitioning, N use efficiency (NUE), and water productivity (WP) were measured. The findings indicated that MSI observably boosted grain yield by 12.0% and protein yield by 9.7%, driven primarily by more spikes and grains per unit area. The DM accumulation of MSI at various growth stages surpassed that of CI. It also improved canopy architecture, increasing leaf area index and specific leaf N while decreasing specific leaf area. Furthermore, MSI enhanced leaf area duration compared to CI. Crucially, MSI altered resource partitioning, reducing the contribution of pre‐anthesis DM and N remobilization to grain, respectively, while increasing the contribution of post‐anthesis accumulation. Although crop evapotranspiration was similar between treatments, the higher yield under MSI resulted in significantly greater WP. The improvement in NUE under MSI was solely attributed to higher N uptake efficiency. MSI is an effective water‐saving strategy for purple wheat production in the NCP, achieving synergistic improvements in yield, WP, and NUE without increasing seasonal water consumption. This technology offers a feasible pathway for sustainable intensification of functional cereal crops in water‐scarce regions.
Abstract Proper management of St. Augustinegrass grown on Florida's sandy soils is critical for water quality protection, yet interactions between municipal fertilizer blackout ordinances, recycled wastewater (RWW) irrigation, and newer cultivars remain understudied. RWW often contains elevated nutrients that may inadvertently contribute to leaching, which is relevant within the realm of nutrient restriction strategies. This 2‐year field study conducted in Davie, FL, evaluated the interactive effects of irrigation source, nitrogen rates (0, 98, and 196 kg N ha − 1 year − 1 ), and blackout scheduling on nutrient leaching and soil nutrient accumulation in CitraBlue St. Augustinegrass. Leachate was extracted weekly via suction lysimeters and analyzed for oxidized nitrogen (NO x ─N), nitrite, ammonium, and orthophosphate. Results identified irrigation source as a primary driver of nutrient export. RWW supplied more than 188 kg N ha − 1 year − 1 from irrigation alone and increased NO x ‐N leaching two‐ to threefold relative to canal water. RWW was the sole source of orthophosphate input in this study. Additionally, RWW significantly increased soil phosphorus (P), sodium (Na), and calcium (Ca) accumulation. Notably, blackout scheduling failed to reduce total nutrient export. Under this scheduling, applications at 196 kg N ha − 1 year − 1 triggered peaks in ammonium and nitrite losses. Conversely, the 98 kg N ha − 1 rate minimized leaching comparable to controls even under blackout scheduling. This study demonstrates that nutrient‐rich RWW is a primary driver of nitrogen and phosphorus presence in leachate and that blackout period fertilization at 196 kg N ha − 1 year − 1 can induce increases in nitrite and ammonium concentration in leachate.
Abstract Cotton ( Gossypium hirsutum L.) growth and production are affected by irrigation management approaches, nitrogen (N) application rates, and plant growth regulation strategies. However, their combined effects on cotton seed composition and yield remain understudied. The objective of this experiment was to investigate how irrigation, N application rate, and mepiquat chloride (MC) application strategy interact to affect cottonseed oil and protein concentrations and seed, oil, and protein yields. The study was conducted in 2022 and 2023 using a split‐split plot design. When N effects were observed, N fertilization positively affected seed yields (kg ha −1 ), protein percentage, and oil and protein yields. When irrigation effects were documented, irrigated cotton produced higher seed yields, oil percentage, and oil yields than dryland. Conversely, protein percentages were increased under yield limiting drought, and protein yields were unchanged. In 2022, there was a significant interaction between N and MC for seed and oil yield, where MC application maximized yields under N fertilization but had no effect under N deficiency. In 2023, a significant interaction between irrigation and N was observed for oil and protein concentration, where oil concentration declined with increasing N rates under dryland conditions but was unaffected by N rate under irrigated conditions. Conversely, protein percentage increased with N rate under dryland conditions. Producers can apply this knowledge to enhance seed composition and the yield of seed, oil, and protein. This work may also have implications for seed or seedling vigor as planting seed composition can be a strong indicator of stand establishment.
Abstract Lentil ( Lens culinaris Medik.) is an important pulse crop worldwide, but its productivity is severely threatened by rust caused by Uromyces viciae‐fabae , making the identification and deployment of resistant genotypes essential for sustainable production. In the present study, a diverse set of lentil lines was screened under natural epiphytotic conditions at Gurdaspur, India, during the 2023–2024 and 2024–2025 winter seasons to evaluate disease reaction and infection type. A subset of 43 lines exhibiting diverse resistance responses in 2023–2024 was further assessed under artificial conditions to analyze resistance components, including latent period (LP50), pustule density, uredial and aecial pustule size, rust severity, infection efficiency (IE), and apparent infection rate. Six lines, namely, DKL 37‐7, DKL 13‐2‐2, EC 1–7, DKL 13‐4‐7, LL 1698, and Vipasha, exhibited immune reactions with no visible symptoms, whereas IC‐241249, DKL 13‐4‐9, DKL 13‐4‐5, EC 1–2, and EC 1–3 showed near‐immune resistance characterized by necrotic flecks. In addition, 36 lines displayed non‐hypersensitive reactions to rust. Significant genotypic variation was observed for all resistance components. LP50 showed strong negative correlations with IE ( r = −0.84), uredial pustule size ( r = −0.74), and spore count per pustule ( r = −0.83), indicating its critical role in slowing disease development. This study not only identifies a novel set of immune and near‐immune lentil lines but also quantitatively dissects the components of partial resistance, highlighting LP50 as the most critical component of field resistance. The identified donors with known resistance types and knowledge of critical components of resistance are important for precision breeding.
Abstract Transposable elements (TEs), which were once relegated to the status of genomic parasites, are today accepted as important agents of plant genome evolution and adaptation. This review integrates evidence pointing to their dual function as drivers of genetic diversity and instability, with a focus on their contribution to phenotypic innovation, stress tolerance, and crop trait control. TEs create structural and regulatory diversity by insertional mutagenesis, cis ‐regulatory sequence donation, and epigenetic interactions, facilitating fast adaptation to environmental stress. Advances in omics technologies have unraveled TE dynamics, showing insertion bias toward genic and regulatory regions and stress‐responsive activation patterns. The influence of the mobilome on crop improvement is emphasized by TE‐derived molecular markers, clustered regularly interspaced short palindromic repeats‐mediated TE regulation, and epigenome editing that minimizes risks of genome instability while tapping TE‐driven diversity. Rice ( Oryza sativa L.) mPing and maize ( Zea mays L.) Hopscotch , for instance, demonstrate TE potential in trait enhancement and domestication. Moreover, multi‐omics integration has defined TEs’ input into stress response and genome plasticity, offering new targets for precision breeding. Challenges remain in modeling TE behavior and weighing adaptive potential against harmful effects, requiring sophisticated computational models and synthetic biology strategies. Interdisciplinary approaches integrating machine learning and synthetic TE design should be prioritized in future research to maximize TE‐mediated crop resilience. With the integration of TE biology and cutting‐edge biotechnologies, global food security issues, fueled by climate change, can be mitigated by the scientific community. This overview situates TEs not merely as genomic leftovers but as essential next‐generation crop requirements, necessitating their strategic location in sustainable agro‐innovation.
Abstract Rusts can cause devastating losses of barley ( Hordeum vulgare L.) in epidemic years. Several reactions to Puccinia hordei ( Rph ) genes/quantitative trait loci (QTLs) for resistance to barley leaf rust (BLR) have been documented. In contrast, there is a dearth of characterized resistance sources against stem rust (SR) caused by Puccinia graminis . This study aimed to genetically characterize novel and known SR and BLR loci in the resistant barley accessions County and BHS248. To achieve this, two recombinant inbred line (RIL) populations ( n = 200) were developed using Hiproly as a rust‐susceptible parent. QTL mapping was performed utilizing genotypic data predominantly generated on the barley 50k iSelect single‐nucleotide polymorphism array and phenotypic results from multi‐year trials in South Africa and USA. A major QTL on chromosome 4H ( QPgt.cg‐4_CH ) for adult plant resistance (APR) to SR race PTKST explained up to 18.2% variation. Another major QTL on 5H (designated QPgt.cg‐5_CH ), also effective to PTKST, is likely RPG‐qtl‐5H‐11_11355 . The APR gene Rph20 (herein named QPh.cg‐5.1_CH ) and all‐stage resistance gene Rph27 (designated QPh.cg‐4_BH ) mapped to 5H and 4H, respectively. For BLR, major effect APR QTLs were identified on 2H and 6H in both populations. Published markers were used to assess if the 6H resistance was contributed by Rph24 , but the latter locus did not map to 6H. Kompetitive allele specific PCR assays were designed spanning most of the major QTL identified. These should be useful in tracking the introgression of rust resistance in local germplasm.
Abstract Repeated applications of natural organic based fertilizers can benefit soil health and potentially suppress some turfgrass diseases. One of the major summer diseases affecting many lawns is brown patch (caused by various Rhizoctonia and Rhizoctonia ‐like species). Information regarding the use of natural fertilizers to reduce brown patch in cool‐season lawns containing turf‐type tall fescue (TTTF) [ Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] is limited. A 5‐year field study was conducted in West Lafayette, IN, to determine the influence of a wide range of commercially available natural organic based fertilizers on brown patch severity in a TTTF lawn. Seven natural organic granular fertilizers were compared to synthetic granular fertilizer, a granular fungicide control (FUNG), and a non‐fertilized control (UTC). Each fertilizer was applied at 24.5 kg N ha −1 in May, June, July, and late September/early October from 2020 to 2024. Visual turf quality, percent disease severity, and various soil properties were measured. During the five growing seasons, natural and synthetic fertilizer sources generally maintained higher visual quality compared to UTC. While the FUNG treatment was the most effective at reducing brown patch severity, select fertilizer sources reduced disease severity by as much as 70% compared to UTC. Brown patch severity for the fertilizer or fungicide treatments was generally not correlated with any soil property measured in this study. When selecting strategies to help reduce dependence on lawn fungicides, these data demonstrate that programmed seasonal applications of select fertilizer sources could be a component of a best management practices program to meet that goal.
Abstract The ability to make reliable, data‐driven crop yield assessments for risk management depends on the quality of the underlying data. This study compares US state‐ and national‐level data from 1986 through 2023 for 10 major field crops using two widely applied approaches: the USDA survey‐based crop condition index (CCIndex) and satellite‐derived vegetation health (VH) indices. The goals are to characterize seasonal tendencies, quantify yield variance, and examine responses to climatic anomalies using both crop monitoring systems. Results indicate that the onset of natural senescence during the reproductive stage marks a critical turning point, as weekly VH indices correlate significantly with yield in the early to mid‐season but lose predictive skill as canopy greenness diminishes; conversely, the CCIndex maintains or even strengthens its yield association through the late season across most crops. Climate‐response analyses reveal that CCIndex ratings adequately capture the nonlinear effects of precipitation and temperatures, whereas VH response is weaker. Collectively, findings support a phenology‐aware blended monitoring strategy—leveraging VH indices for early detection and the CCIndex for late‐season yield relevance and agronomic nuance. This multi‐decadal, multi‐crop evaluation establishes a robust baseline for operational crop‐condition predictability and highlights opportunities to fuse survey and remote‐sensing data to enhance yield forecasting and climate resilience.
Abstract Modernizing cassava breeding programs (CBPs) is critical to increase genetic gain, close the yield gap, and ensure food availability, accessibility, and affordability to support livelihood transformation and economic development in sub‐Saharan Africa (SSA). The CBP at the International Institute of Tropical Agriculture, a pioneer in cassava ( Manihot esculenta Crantz) improvement in SSA, has undergone modernization. We reflect on the progress made over the past years to improve efficiency and effectiveness of the program. Breeding strategies and methods that have been employed or explored, which could contribute to the timely development of demand‐led, improved varieties, are reviewed. Emerging tools and advanced technologies aimed at accelerating product development are highlighted. In addition, we evaluate the program's delivery and impact over the years, as well as the challenges encountered. Progress in mechanization of farm operations and prospects are highlighted. We consider other key drivers that have contributed to the observed transformation of the breeding program. We acknowledge the key role of tools integration, appropriate human resource capacity, committed transdisciplinary teams, collaboration, and partnerships. Continuous refinement of breeding methodologies, optimization of key components of the breeder's equation, adoption of a culture of continuous improvement, and sustained funding are essential to transform CBPs in SSA and to expediting the development of customer‐tailored varieties.
Abstract Vegetabling resulted in the development of a unique food source comprised of highly immature plant organs that delivers desirable textures, flavors, and nutritional diversity to human diets. In contrast to some dry‐seeded crops, perishable vegetables require enormous inputs of energy and technology during the postharvest period to preserve their quality. A vast cold chain to preserve fresh produce and myriad technologies designed to dry, salt, freeze‐dry, can, pickle, freeze, juice, and irradiate vegetables consumes enormous financial and human resources that must be deployed quickly before vegetables rot. This gave us purpose. But despite our efforts, estimates indicate up to 45% of vegetables are wasted due to spoilage. While perhaps unanticipated during domestication efforts, the consequences of vegetabling have resulted in far‐reaching technological, energetic, and societal complexities that extend to the ability to control microbial growth, significantly reduce water activity in moisture‐filled plant tissues, and stop time by producing a shelf‐stable vegetable product that can last for years. Successfully processing perishable plant products represents a triumphal consequence of the vegetabling project for at least two primary reasons: a dramatic increase in both food security and economic value. Yet vegetabling can only continue as long as humans are willing to consistently provide efforts to preserve vegetable tissues, a situation that is not required for dry‐seeded crops. By creating them, humans have entered into a bargain with vegetables that is Sisyphean in nature. Vegetables without us would revert to non‐perishable, mature plant organs and limit our dietary diversity; vegetables with us require Herculean efforts at preservation, providing us with purpose, but not allowing us to rest.
Abstract Delayed sowing can reduce winter wheat ( Triticum aestivum L.) yield and increasing seeding rate is commonly proposed to compensate for some of the negative effects, but tillering plasticity, shortening of critical period, and environmental conditions make the yield response uncertain. We analyzed worldwide published data from 40 experiments that factorially combined sowing dates and seeding rates to (i) evaluate whether the relationship between seeding rate and delayed sowing in winter wheat was additive, synergistic, or antagonistic and (ii) evaluate the impact of sowing date on the critical seeding rate, that is, the rate to achieve 95% of peak yield. The compiled database contained 658 mean yields from 0.3 to 10.5 Mg ha −1 . The relationships between sowing date and seeding rate were classified as either positive or negative additive, antagonistic, or synergistic. Out of 169 sowing date × seeding rate relationships, 40% were negative additive and 25% were negative antagonistic, independent of the yielding environment. Negative additivity suggests that in many environments, the usual seeding rate was already close to or above the critical seeding rate required to maximize yield at delayed sowing. Negative antagonistic relationships indicate that higher seeding rates partially compensated for the yield reduction with late sowing. The remaining relationships were mostly positive additive or antagonistic, with synergistic effects being rare. Michaelis–Menten models were fitted to estimate critical seeding rate, which increased from 292 seeds m −2 under the usual sowing date to 463 seeds m −2 for ≥30‐day sowing delay. In environments where yield was reduced due late sowing, higher seeding rates partially offset yield losses. Our results reinforce that site‐specific seeding rate recommendations should account for the time of sowing.
Abstract The interactive effects of nitrogen (N) and mepiquat chloride (MC) on yield and key physiological traits have received limited attention in the primary literature. This study was aimed to (1) evaluate the effects of N rate and MC application strategy on yield‐altering physiological processes, lint yield, and fiber quality and (2) quantify relationships between lint yield and physiological responses at peak bloom and cutout stages. A field experiment was conducted in 2023 and 2024 near Tifton, GA, using a split‐plot design with three N rates (0, 135, and 270 kg N ha −1 ) and three MC strategies (control, moderate, and aggressive). Variables assessed included lint yield, gin turnout, fiber quality traits, fraction of intercepted photosynthetically active radiation (IPAR f ), radiation use efficiency, above‐ground biomass (AGB), N uptake, and crop growth rate. Nitrogen fertilization increased lint yield (57‐91%), IPAR f , AGB, and N uptake, with no yield benefit above 135 kg N ha −1 . Yield increased by 18%–25% with MC application in 2024, but no impact was observed in 2023. No significant N × MC interaction was observed for yield. Regression analysis showed that IPAR f and AGB at peak bloom were the most consistent predictors of lint yield. Nitrogen and MC effects on fiber quality varied by year. Nitrogen application had a consistent positive effect on yield and physiological traits. MC showed variable effects on lint yield across years. IPAR f and AGB and N uptake at the peak bloom are important indicators of N‐ or MC‐management‐driven yield variation in cotton.
Abstract Red clover ( Trifolium pratense L.) is a widely grown perennial forage legume that supports sustainable livestock production through its high nutritive value and bioactive isoflavones. Future climate change, particularly warming and increased rainfall, may influence forage accumulation and isoflavone concentrations. However, field evidence integrating the combined effects of these climate factors remains limited. To address this gap, we conducted a 2‐year field experiment in central Kentucky manipulating temperature (+3°C, day/night) and precipitation (+30% of the long‐term mean) on red clover (cv. Kenland). Plants were harvested multiple times in a growing season to mimic hay production, and isoflavones were quantified. Warming reduced total isoflavone concentrations by 15% though responses varied by cutting and year, while precipitation alone did not affect total isoflavone concentrations. However, elevated temperature stimulated daidzein concentration in late summer, and the effects of added precipitation on daidzein differed among cuttings. Warming decreased red clover aboveground biomass by 14% across years, whereas added precipitation tended to increase biomass by a similar magnitude but did not significantly offset heat‐related losses. These results suggest that future climatic conditions may reduce red clover productivity and total isoflavone concentrations. Additional rainfall showed limited evidence of mitigating warming‐driven reductions in biomass and isoflavone concentrations, and warming may induce compound‐specific changes in isoflavones (e.g., daidzein). These findings have mixed implications for forage–livestock systems. Decreased isoflavone concentrations (e.g., formononetin) may reduce reproductive risks in livestock, whereas decreases in other isoflavones could diminish benefits related to animal performance and environmental sustainability.
Abstract Freezing events in subtropical regions are becoming increasingly unpredictable, posing significant risks to plant survival and livestock systems dependent on warm‐season grasses. Species within the Plicatula group of Paspalum offer valuable agronomic potential as forage crops and exhibit substantial variability in freezing tolerance. To assess this variability, we conducted a 3‐year field trial involving 28 accessions, using both visual and normalized difference vegetation index (NDVI)‐based evaluations of leaf damage, alongside a controlled freezing experiment in a growth chamber. Results in field and controlled conditions were moderately correlated ( r = 0.48–0.53), validating the use of controlled assays for screening. Based on performance, four accessions were selected for anatomical analysis: two tolerant (ML1 and U100) and two sensitive (Q4334 and U44). Metaxylem vessel diameters in the apical section of the youngest leaf (leaf 1) were smaller in tolerant accessions (14.78 and 19.37 µm) and larger in sensitive ones (22.20 and 21.64 µm), with correlation coefficients of 0.64 (visual) and 0.59 (NDVI). Additionally, tolerant accessions exhibited fewer parenchymal tissues and a greater density of vascular bundles in marginal leaf sections. In conclusion, our results confirm high variability in freezing tolerance within the Plicatula group, with P. plicatulum and P. guenoarum showing greater resilience compared to P. atratum and P. lenticulare . Controlled freezing tests at −3°C effectively differentiate field performance, and anatomical traits, particularly in apical sections of young leaves, serve as potential markers of freezing tolerance, likely due to their greater exposure to frost.
