Growth Of Sunflower Research Articles

Effect of Integrated Nutrient Management Practices on Yield Attributes and Nutrient Content and Uptake in Sunflower (Helianthus annuus L.) under Nagaland Condition

Background: Sunflower is an important oilseed crop. At present, the production of sunflower crop is less due to poor nutrient management practices. Excessive use of chemical fertilizers not only increases the cost of production but also leads to deterioration of soil and human health. The integrated use of nutrients from fertilizer and organic manure sources seems to be the need of the hour. Thus, integrated nutrient management holds great promise in meeting the growing nutrient demand of modern agriculture. Methods: A pot experiment was conducted during pre-kharif season (March-June) of 2022 to study the effect of integrated nutrient management on growth, yield and quality of Sunflower. The experiment was laid out in Completely Randomized Design with three replications and consisted of seven treatments viz., T1, T2, T3, T4, T5, T6 and T7. Result: T7 (FYM 10 t ha-1 + 100% RDN) recorded highest in yield attributing characters i.e., head diameter (14.50 cm), number of seeds head-1 (783.33), seed yield (26.67 g pot-1) and stover yield (48.33 g pot-1). Maximum NPK uptake for both seed and stover was recorded highest in FYM @ 10 t ha-1 + 100% RDN. Maximum available soil N was recorded in T7(FYM @ 10 t ha-1 + 100% RDN) with 328.96 kg ha-1 while maximum available soil P and K was recorded in T2 {100% RDF (60:40:60) kg ha-1} with 29.25 kg ha-1 and 230.79 kg ha-1, respectively.

Microbiome and nutrient dynamics of organic manures for precision NPK management in sunflower (Helianthus annuus L.)

AbstractOrganic manure plays an important role in soil fertility, microbial communities and sustainable agricultural strategies. In organic cultivation of crops, manures are mostly used without any calculation of the nutrients added to soil through their application. The quantities of nutrients supplied by the organic manures to the crop have to equalize the quantity of nutrients supplied by inorganic chemical fertilizers, in order to replace chemical fertilizers in organic farming. Since the organic manures release nutrients slowly into the soil over a period of time, the availability of nutrients to the standing crop requires precise estimation. In the present study, the amount of nutrients available in the soil as well as in all the manures was calculated. Moreover, the study included metagenomic analysis of different organic manures used by farmers and gives an insight to the role the microbiome plays in plant growth. Using a formula of STCR‐IPNS (soil test crop response integrated plant nutrition system), the quantities of different combinations of organic manures required to supply nitrogen, phosphorus and potassium (NPK) to sunflower plants were calculated. Organic manure combinations using animal bone meal, neem cake, farmyard manure and vermicompost recorded better growth and yield responses in sunflower plants compared to inorganic chemical fertilizers. Based on the estimation of NPK in the individual manures and in the soil, pot experiments were carried out to understand the effect of organic manures as well as inorganic fertilizers in the vegetative and reproductive growth of sunflower.

Effect of bio-fertilizer and sulphur on growth and yield of sunflower (Helianthus annuus L.)

Effect of bio-fertilizer and sulphur on growth and yield of sunflower (Helianthus annuus L.)

The Effect of Different Doses of Nitrogen and Seed Treatment with Biofertilizers on Growth, Yield and Seed Quality of Sunflower (Helianthus annus L.)

Aims: To study the effect of Different Doses of Nitrogen and Seed Treatment with Biofertilizers on Growth, Yield and Seed Quality of Sunflower. Study Design: The experiment was laid out in a randomized block design with eleven treatments replicated thrice. Place and Duration of Study: The field experiment was conducted during rabi season of 2019-20, 2020-21, 2021-22 and 2022-2023 in the Instructional Farm of Ramkrishna Ashram Krishi Vigyan Kendra, Nimpith, South 24 Parganas, West Bengal. Methodology: The experiment was carried out in randomized block design with eleven treatments and replicated thrice. The treatments were Control, 50% N, 100% N (90 kg N/ha), Azospirillum (seed treatment), Azatobacter (seed treatment), Azospirillum +Azatobacter (seed treatment), 50% N + Azospirillum (seed treatment), 50% N + Azatobacter (seed treatment), 50% N +Azospirillum + Azatobacter (seed treatment), 75% N + Azospirillum + Azatobacter (seed treatment) and 100% N + Azospirillum + Azatobacter (seed treatment). A common dose of Nitrogen@ 90kg/ha, phosphorus @90kg/ha and potash @40kg/ha were applied. Results: Higher head diameter (13.82 cm), 1000 seed weight (65.50 g), seed yield (1830 kg/ha), oil yield (628.80 kg/ha), gross return (Rs.48581), net return (Rs.26368) and B:C (2.19) than all other treatment followed by T10 (75% N + Azospirillum + Azotobacter) and T3 (100% N) which were statistically at par with each other. Conclusion: On the basis of all parameter as well as economics it can be concluded that treatment T10 (75% N + Azospirillum + Azotobacter) can be recommended for better benefit and sustainable production of sunflower. The results of this experiment showed that use of chemical fertilizers can be reduced by using a combination of bio-fertilizers and inorganic nitrogen fertilizer.

Analysis of Germination, Seedling Growth, Photosynthetic Efficacy and Antioxidative Enzyme Activity in Sunflower Under Allelopathic Stress Caused by Cynodon dactylon L.

Analysis of Germination, Seedling Growth, Photosynthetic Efficacy and Antioxidative Enzyme Activity in Sunflower Under Allelopathic Stress Caused by Cynodon dactylon L.

Influence of Nano Urea and Nano DAP on Growth and Productivity of Sunflower (Helianthus annuus L.) During kharif season

A two years field experiment was conducted at AICRP on sunflower, Zonal agricultural research station, UASB, GKVK, Bengaluru during kharif, 2022 and 2023 to study the effect of nano urea and nano DAP on growth and productivity of sunflower. The experiment was laid out in Randomized Complete Block Design with thirteen treatments (50 % RDN+ Nano N @ 4 ml, 50 % RDN+ Nano N @ 6 ml, 75 % RDN+ Nano N @ 4 ml, 75 % RDN+ Nano N @ 6 ml, 50 % RDNP + Nano N & P @ 4 ml, 50 % RDNP + Nano N & P @ 6 ml, 75 % RDNP + Nano N & P @ 4 ml, 75 % RDNP + Nano N & P @ 6 ml, RDF + Normal urea spray @ 1%, RDF+ DAP spray @ 1%, RDF+ FYM, RDF and absolute control) each replicated thrice. The results revealed that significantly higher plant height (199.89 cm), number of leaves per plant (30.26), leaf area (5557 cm2 plant-1), leaf area index (3.09), total dry matter production (146.70 g plant-1), capitulum diameter (19.06 cm), no. of seeds per capitulum (1147), seed yield (2026 kg ha-1) and stalk yield (4395 kg ha-1) were recorded with the application of RDF+ FYM and it was found on par with application of 75 % RDN+ Nano N @ 6 ml.

Comprehensive identification of GASA genes in sunflower and expression profiling in response to drought

Drought stress poses a critical threat to global crop yields and sustainable agriculture. The GASA genes are recognized for their pivotal role in stress tolerance and plant growth, but little is known about how they function in sunflowers. The investigation aimed to identify and elucidate the role of HaGASA genes in conferring sunflowers with drought tolerance. Twenty-seven different HaGASA gene family members were found in this study that were inconsistently located across eleven sunflower chromosomes. Phylogeny analysis revealed that the sunflower HaGASA genes were divided into five subgroups by comparing GASA genes with those from Arabidopsis, peanut, and soybean, with members within each subgroup displaying similar conserved motifs and gene structures. In-silico evaluation of cis-regulatory elements indicated the existence of specific elements associated with stress-responsiveness being the most abundant, followed by hormone, light, and growth-responsive elements. Transcriptomic data from the NCBI database was utilized to assess the HaGASA genes expression profile in different sunflower varieties under drought conditions. The HaGASA genes expression across ten sunflower genotypes under drought stress, revealed 14 differentially expressed HaGASA genes, implying their active role in the plant’s stress response. The expression in different organs revealed that HaGASA2, HaGASA11, HaGASA17, HaGASA19, HaGASA21 and HaGASA26 displayed maximum expression in the stem. Our findings implicate HaGASA genes in mediating sunflower growth maintenance and adaptation to abiotic stress, particularly drought. The findings, taken together, provided a basic understanding of the structure and potential functions of HaGASA genes, setting the framework for further functional investigations into their roles in drought stress mitigation and crop improvement strategies.

Plant Density and Location: Optimization of Growth and Quality of Cut Sunflower in Tropical and Subtropical Environments

The cultivation of sunflower (Helianthus annuus L.) as a cut flower stands out in floriculture due to its aesthetic beauty and commercial value. Understanding how cut sunflower genotypes adapt to different edaphoclimatic regions and management practices is essential to optimize flower quality and productivity. This study aimed to evaluate the effect of plant density and location on the development, growth, and quality of cut sunflower in tropical and subtropical environments. Plant densities of 10, 20, 30, 40, and 50 plants/m2 were evaluated in tropical climate and subtropical climate using a randomized block design in a factorial scheme. Results showed significant differences between locations for plant height, capitulum and stem diameter, final number of leaves, leaf area, leaf area index, phyllochron, and the developmental cycle. Plant density significantly influenced these variables except for plant height and developmental cycle. The interaction between location and plant density was significant only for capitulum diameter and final leaf number. The findings indicate that both planting density and location significantly influence the developmental cycle of cut sunflowers, with lower densities favoring more robust plants at harvest. A density of 30 plants/m2 is recommended for efficient space use without significantly compromising floral stem quality. All produced stems are marketable, suggesting that adjusting planting density can optimize production without compromising quality, adapting to specific regional conditions.

An Excessive K/Na Ratio in Soil Solutions Impairs the Seedling Establishment of Sunflower (Helianthus annuus L.) through Reducing the Leaf Mg Concentration and Photosynthesis

In saline conditions, establishing healthy seedlings is crucial for the productivity of sunflowers (Helianthus annuus L.). Excessive potassium (K+) from irrigation water or overfertilization, similar to sodium (Na+), could adversely affect sunflower growth. However, the effects of salt stress caused by varying K/Na ratios on the establishment of sunflower seedlings have not been widely studied. We conducted a pot experiment in a greenhouse, altering the K/Na ratio of a soil solution to grow sunflower seedlings. We tested three saline solutions with K/Na ratios of 0:1 (P0S1), 1:1 (P1S1), and 1:0 (P1S0) at a constant concentration of 4 dS m−1, along with a control (CK, no salt added), with five replicates. The solutions were applied to the pots via capillary rise through small holes at the bottom. The results indicate that different K/Na ratios significantly influenced ion-selective uptake and transport in crop organs. With an increasing K/Na ratio, the K+ concentration in the roots, stems, and leaves increased, while the Na+ concentration decreased in the roots and stems, with no significant differences in the leaves. Furthermore, an excessive K/Na ratio (P1S0) suppressed the absorption and transportation of Mg2+, significantly reducing the Mg2+ concentration in the stems and leaves. A lower leaf Mg2+ concentration reduced chlorophyll concentration, impairing photosynthetic performance. The lowest plant height, leaf area, dry matter, and shoot/root ratio were observed in P1S0, with reductions of 27%, 48%, 48%, and 13% compared to CK, respectively. Compared with CK, light use efficiency and CO2 use efficiency in P1S0 were significantly reduced by 13% and 10%, respectively, while water use efficiency was significantly increased by 9%. Additionally, improved crop morphological and photosynthetic performance was observed in P1S1 and P0S1 compared with P1S0. These findings underscore the critical role of optimizing ion composition in soil solutions, especially during the sensitive seedling stage, to enhance photosynthesis and ultimately to improve the plant’s establishment. We recommend that agricultural practices in saline regions incorporate tailored irrigation and fertilization strategies that prioritize optimal K/Na ratios to maximize crop performance and sustainability.

Efficacy of Chicken Feather Vermicompost From Poultry Waste for Sunflower Growth with a Sustainable Development SDG

Objective: This study aims to evaluate the effect of different chicken feather vermicompost rates collected from poultry waste and applied as organic fertilizers on the growth performance of sunflowers. Theoretical Framework: In this study, the chicken feather vermicompost was formulated based on the combination of chicken feathers, chicken dung, mushroom medium residue, and banana trunks. The completed chicken feather vermicompost was applied to the sunflower to evaluate the growth performance. Method: The methodology involved five different rates; T1 Control (300g organic fertilizer), T2 (200g chicken feather vermicompost), T3 (300g chicken feather vermicompost), T4 (400g chicken feather vermicompost), and T5 (500g chicken feather vermicompost). Total of 35 sunflower plants were applied with 5 treatments for 7 replications. Results and Discussion: The physio-chemical properties of chicken feather vermicompost, such as EC, pH, moisture, and temperature were optimal for decomposition organism growth and reproduction. The population and reproduction of Eudrilus eugeniae in vermicompost are influenced by all ingredients used in vermicomposting. The results show that the different chicken feather vermicompost rate affects sunflowers' growth performance. T5 exhibits the best performance in the number of flowers, number of leaves, relative chlorophyll content, fresh weight, and dry weight. Research Implications: By considering the chicken feather vermicomposting method, it is useful in reducing environmental pollution by managing waste efficiently. Originality/Value: This study provides a new technique for maximizing poultry waste through the chicken feather vermicomposting process and identifies the optimum rate of chicken feather vermicompost on growth performance of sunflowers for sustainable agriculture.

Response of blue light in different proportions on the growth & flowering in sunflower

Due to the light sensitivity of sunflowers, regulating spectral composition holds significant potential for optimizing sunflower growth and flowering to meet market demands. In this study, sunflower plants were exposed to white light (W200, control) and three levels of blue light (B40R80Fr80 with blue light intensity of 40 µmol m−2 s−1; B67R67Fr67 with blue light intensity of 67 µmol m−2 s−1; B100R50Fr50 with blue light intensity of 100 µmol m−2 s−1) under an overall irradiance level of 200 µmol m−2 s−1 for 60 days. The aim was to investigate the effects on sunflower morphology regulation, leaf growth, and flowering. Results demonstrated that the growth of sunflowers under B40R80Fr80 treatment with 20 % blue light inhibited plant height compared with B67R67Fr67 and B100R50Fr50 treatments. The highest total leaf dry weight was observed in sunflower leaves under the B100R50Fr50 treatment. Leaves under B67R67Fr67 treatment enhanced activities of Glyceraldehyde 3-phosphate dehydrogenase, Fructose-1,6-bisphosphate aldolase, and soluble starch synthase, along with a 10.4 % increase in Rubisco activity compared with B100R50Fr50 treatment. The sucrose and starch content under B67R67Fr67 treatment increased by 41.0 % and 19.1 % than those of B100R50Fr50 treatment, respectively. Sunflower plants under B67R67Fr67 treatment significantly improved flower disk diameter and No. of petal per flower compared with W200 treatment. Phenotype-assisted transcriptome analysis revealed that B67R67Fr67 treatment on sunflower leaves had positive effects on circadian rhythm-related genes associated with flowering [CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) and FLOWERING LOCUS T (FT)], compared with B100R50Fr50 treatment. Additionally, four genes related to GA metabolism were identified for flower development regulation; LOC110884159 and LOC110890361 (GID1B) were up-regulated under B67R67Fr67 treatment. Sunflower leaves under B67R67Fr67 treatment increased GA content and induced the GA pathway related to circadian rhythm, compared with those of B100R50Fr50 treatment. Consequently, the implementation of B67R67Fr67 treatment led to improved circadian rhythm and GA pathway activation, resulting in induced flowering to fulfill market demands for sunflowers.

Improving Sunflower Yield through Liming and Phosphorus Fertilizer Application in the South-Central Coastal Region of Bangladesh

Along with salinity, low soil pH is the major constraint for growing winter crops in the south central coastal region of Bangladesh. Extensive research has been done to manage soil salinity, where managing low soil pH for crop production is scarce. The aim of the experiment was to improve sunflower (Helianthus annuus L. cv. Hybrid Unisun) yield through liming and phosphorus fertilizer application in the acidic saline soil of Amtali upazila of Barguna district, Bangladesh. During the winter season of 2024 a field experiment was carried out comprising two rates of lime 0 and 2 t ha-1 and four levels of phosphorus (P) having 0, 12, 24 and 36 kg P ha-1 using RCBD design. Lime application at 2 t ha-1 rate significantly increased stem girth, head diameter, number of seeds per head, 1000-seed weight, and seed, stover and root yields of sunflower. The application of P up to the highest level (36 kg P ha-1) significantly increased the growth and yield of sunflower. Lime application increased the soil pH by 0.72 unit compared to non-liming plot. The application of lime (2 t ha-1) along with 36 kg P ha-1 recorded the highest sunflower seed yield of 3.21 t ha-1 in the soil of Amtali upazila of Barguna district, Bangladesh. The benefit cost ratio (BCR) of different rates of P application without liming ranged from 5.28-10.09 but it decreased drastically while P was applied with lime having the BCR between 0.15-1.82. J Bangladesh Agril Univ 22(3):352-359, 2024

Optimizing Oxalic Acid Application Regime to Maximize Sunflower Remediation Efficacy in Cd-Contaminated Soils

The exogenous application of oxalic acid is a potential approach to amplifying phytoremediation performance on Cd-contaminated soils. However, few studies explore the optimal oxalic acid application regime from a perspective of coupling different concentrations and timings to maximize Cd removal rate. Given this, a pot experiment was conducted using oil sunflower (Helianthus annuus L.) as the test plant. Oxalic acid was added to the pots at concentrations of 1, 2, 3, 4, 5, and 6 mmol/kg at 20, 30, 40, and 50 days after emergence. A control (CK) without exogenous oxalic acid was also included. We examined the discrepancies in various soil Cd forms, sunflower height, plant non-protein thiol (NPT) levels, and soil Cd remediation efficiency under different oxalic acid application regimes. The results showed that applying oxalic acid at a concentration of 4 mmol/kg reduced the proportion of Fe-Mn oxide Cd and organic Cd compared to the control (CK), while increased the proportion of available Cd. The optimal application time is 30 or 40 days after emergence. The addition of exogenous oxalic acid promoted the growth of sunflowers, with the greatest increase in plant height observed when 4 mmol/kg oxalic acid was applied at 30 days after emergence. Exogenous oxalic acid enhanced the absorption of Cd by sunflower roots, with the total Cd accumulation in roots, stems, and leaves being higher than in the control (CK). When 4 mmol/kg oxalic acid was applied at 30 days after emergence, the total Cd accumulation in roots, stems, and leaves was highest. Under different application times and concentration levels of oxalic acid, Cd accumulation was highest in roots, followed by leaves, with stems showing the lowest accumulation. The NPT content in each part is as follows: root > stem > leaf. Applying 5 mmol/kg oxalic acid after 30 days of sunflower emergence resulted in relatively higher total NPT content in roots, stems, and leaves compared to the control (CK). The TOPSIS model was used for comprehensive evaluation, which showed that 4 mmol/kg oxalic acid application at 30 days after emergence could be used as the optimal oxalic acid application regime for phytoremediation. These findings indicate that the addition of oxalic acid effectively promoted the absorption of Cd by sunflower and increased the efficiency of Cd removal from the rhizosphere soil, with the optimal removal of soil Cd achieved by applying oxalic acid at a concentration of 4 mmol/kg 30 days after the emergence of oilseed sunflower seedlings.

The role of Aspergillus flavus in modulating the physiological adjustments of sunflower to elevated CO2 and temperature

Exploring the interactions between plants and foliar endophytic fungi under varying climatic conditions is crucial for harnessing endophytes that enhance plant resilience to environmental stressors. This study examines the role of a specific strain of Aspergillus flavus as an endophyte in sunflowers under standard and altered CO2 and temperature regimes. We assessed the impact of this fungus on physiological traits such as chlorophyll and flavonoid content, gas exchange, and Chlorophyll a fluorescence using open-top chambers simulating ambient (∼420 µmol mol−1) and elevated (∼880 µmol mol−1) CO2 levels, along with a temperature increase of 3°C. The findings indicate that A. flavus promotes nitrogen assimilation and chlorophyll production under ambient conditions, potentially enhancing sunflower growth and photosynthetic performance. However, under elevated temperatures (eT), inoculation with A. flavus resulted in decreased biomass and reduced Photosystem II efficiency. Elevated CO2 (eCO2) conditions also led to unexpected negative effects, with reductions in foliar nitrogen, leaf area, and light capture efficiency, culminating in diminished biomass. When both elevated CO2 and temperature conditions were combined (eCO2eT), the interaction further impaired Photosystem II efficiency, suggesting exacerbated physiological stress. These results demonstrate that environmental modifications can transform A. flavus from a beneficial endophyte to a potential pathogen, highlighting the dual nature of plant-fungal interactions. This study underscores the complexity of these relationships under changing climatic conditions and suggests a cautious approach to the agricultural use of endophytes to ensure plant health and productivity.

Boosting resilience and yields in water-stressed sunflower through coordinated irrigation scheduling and silica gel applications

Sunflower (Helianthus annuus L.) is a globally significant oilseed crop, yet its yields may suffer due to water deficiency. A field experiment was conducted through two summer seasons (2021 and 2022) at the agricultural research station, Luxor, Egypt, to study the effects of irrigation regime, cultivar selection, and silica gel application on sunflower growth and yield parameters. The experiment utilized a split-split plot design with three irrigation levels based on field capacity (85 %, 70 %, 55 %), three sunflower cultivars (Sakha-53, Giza-102, and Giza-120), and two Silica gel treatments (0 and 300 kg/ha). Analysis of variance revealed significant effects of irrigation (P < 0.001) on all measured traits except 100-seed weight. Utilizing various cultivars also revealed substantial influence, affecting most traits consistently across the two seasons. Silica gel application positively impacted head diameter, 100-seed weight, oil content, and oil yield (P < 0.05). Furthermore, treatments combining moderate irrigation with silica gel application exhibited the highest water productivity, with values reaching 1.35 kg/m³ in the first season and 1.38 kg/m³ in the second season, indicating the synergistic effects of improved water management and silica gel on crop water use efficiency. Multivariate analysis of principal component analysis and clustering heatmap revealed that treatment combinations such as I2S1 (moderate irrigation with silica gel) optimized sunflower productivity, particularly for seed yield and oil content, reinforcing the importance of tailored agronomic practices for maximizing crop performance under varying environmental conditions. These findings underscore the significance of integrated agronomic approaches in enhancing sunflower productivity while promoting sustainable crop management practices.

Synergic effect of nano urea, sulphur and boron fertilization on growth, yield and quality of sunflower (Helianthus annuus L.)

Synergic effect of nano urea, sulphur and boron fertilization on growth, yield and quality of sunflower (Helianthus annuus L.)

A Novel Method for the Enhancement of Sunflower Growth from Animal Bones and Chicken Feathers.

The present study aimed at converting meat industry waste, particularly waste bones and chicken feathers, into biochar to recycle valuable nutrients present in it, which ultimately become part of the municipal waste. The bone biochar (BB) and feathers biochar (FB) were prepared at 550 °C, and their potential was evaluated as an organic amendment for the growth of sunflower. The ash content (AC) and fixed carbon (FC) improved significantly in prepared biochars as compared to raw feedstock. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analyses signaled the occurrence of various functional groups viz. amide group and hydroxyapatite, porosity, and multiple nutrients. Application of BB and FB in potted soil alone as well as in composites (1:1, 1:2, 2:1) at 1%, 3%, and 5% (w/w) and synthetic fertilizer significantly increased soil pH, electrical conductivity (ECe), organic matter (OM) and water holding capacity (WHC), while reducing the bulk density (BD). The growth of plants grown in soil treated with a 2:1 composite of feathers and bone biochar at 5% application rate showed significantly greater differences in plant height, total chlorophyll content, and plant dry weight than the control but was comparable to growth with chemical fertilizer, rendering it a potential alternative to chemical-based synthetic fertilizer.

Endophytic Beauveria bassiana promotes sunflower growth and confers resistance against sclerotinia disease

Endophytic Beauveria bassiana promotes sunflower growth and confers resistance against sclerotinia disease

Growth and yield response of sunflower to varied nitrogen levels and foliar nano urea and zinc applications

Growth and yield response of sunflower to varied nitrogen levels and foliar nano urea and zinc applications

Sunflower-YOLO: Detection of sunflower capitula in UAV remote sensing images

Accurate identification and monitoring of sunflower capitula are crucial for field phenotypic analysis, cultivation management, phenological monitoring, and yield prediction. Manual observation, however, faces significant challenges due to the complexity of field environments and the morphological diversity of sunflower capitula. Unmanned Aerial Vehicles (UAVs) have emerged as an ideal platform for monitoring sunflower capitula due to their low cost and high spatiotemporal resolution. This study introduces Sunflower-YOLO, an enhanced model based on YOLOv7-tiny, designed for detecting sunflower capitula in UAV remote sensing images. The model effectively identifies sunflower capitula and distinguishes between three specific states: open, half-open, and bud. Sunflower-YOLO incorporates several key improvements: the SiLU activation function replaces the original LeakyReLU, enhancing the model’s nonlinear expression capability; a shallow high-resolution feature map and an additional detection head for small targets are introduced during the feature fusion stage to improve the detection performance of small capitula; and the integration of deformable convolution and the SimAM attention mechanism enhances the ELAN structure in the backbone, creating a new DeformAtt-ELAN structure that improves the model’s ability to capture morphological variations and reduces noise interference. Experimental results demonstrate that Sunflower-YOLO achieves precision, recall, and mAP@0.5 of 92.3 %, 89.7 %, and 93 %, respectively, marking improvements of 4.2 %, 4.2 %, and 3.7 % over the original YOLOv7-tiny model. The average precision (AP) for the three growth states is 98.7 %, 93.4 %, and 87 %, with AP for the half-open and bud states improving by 6.5 % and 4.7 %, respectively. The model’s FLOPs is 17.7 G, its size is 13.8MB, and it achieves an FPS of 188.52. Compared to current mainstream state-of-the-art (SOTA) models for object detection, Sunflower-YOLO achieves the highest mAP@0.5 in detecting multiple types of sunflower capitula. The constructed capitulum density map offers a practical view for observing sunflower growth status. This study highlights the immense potential of combining UAV remote sensing technology with YOLO object detection algorithms in monitoring sunflower capitula and their growth processes, providing an innovative and effective approach for precision agriculture practices.