Effect of foliar application of chelated micronutrients on yield and quality of rabi sunflower (Helianthus annuus L.)

Introduction

Sunflower (Helianthus annus L) is the important edible oilseed crop in importance after Soybean, Groundnut, Rapeseed and Mustard at the National and International level. It is cultivated in an area of 2.25 lakh ha with a production of about 2.70 lakh tonnes and productivity of 1201 kg ha -1 , which is lower than the world average of 1808 kg ha -1 (Anonymous, 2025) [1] , indicating wide scope for improving the yield potential. He has been proved as a highly promising crop under different under different agroclimatic zones of India because of thermo-sensitivity and high production potential. The application of micronutrients has positive effects on the growth of sunflowers, including plant height, number of leaves and dry matter production per plant (Siddiqui et al., 2009) [2] . The application of micronutrient fertilizers in the cultivation zone may not reached the crop requirement for root growth and nutrient use. The use of micronutrients plays a crucial role in enhancing the percentage of seed setting and influencing the growth and yield of sunflower (Kumbhar et al., 2017) [3] . Foliar application is the spraying of fertilizer solutions containing one or more nutrients on the foliage of growing plants. Several nutrients' elements are readily absorbed by leaves when they are dissolved in water and sprayed on them. Chelated micronutrients are essential metallic plant nutrients (Iron, Zinc, Copper and Manganese) bounded by an organic compound to protect them from soil interactions that rendered them unavailable. Though, these nutrients are required in low quantity, their deficiencies are responsible for low quality and low productivity of sunflower. Raghu et al., 2017 [4] reported that nitrogen uptake by sunflower significantly improved with soil and foliar application of micronutrients along with RDF. In the present study, the efficacy of chelated micronutrients like Zn, Fe and Boron is evaluated.

Materials and Methods

A field experiment was conducted at the Oilseeds Research Centre, Dr Panjabrao Deshmukh Krishi Vidyapeeth, Akola during rabi season from 2023-24 to 2025-26 to study the effect of chelated micronutrients on yield and quality of sunflower. This experiment was laid out in Randomized Block Design with three replications. The experiment was framed with seven treatments viz., T 1 -Absolute control, T 2 -GRDF 80:60:30 NPK kg ha -1 (P supplied through SSP) + 5-ton FYM/ha, T 3 -GRDF + foliar application of chelated micronutrients mixture 0.25 % at 35 & 55 DAS, T 4 -GRDF + Foliar application of Zn EDTA @ 0.25 % at 35 & 55 DAS, T 5 -GRDF + foliar application of Fe EDTA @ 0.25 % at 35 & 55 DAS, T 6 -GRDF + FA of Zn EDTA + Fe EDTA @ 0.25 % at 35 & 55 DAS and T 7 -GRDF + foliar application of Zn EDTA + Fe EDTA @ 0.25 % + FA of 0.2% Boron at 35 and 55 DAS were laid out in plots of 5.4 m x 4.5 m. The experimental field was neutral in reaction (pH 7.70), Non saline (0.19 dSm -1 ), low in organic carbon (4.59 g kg -1 ), low in available N (210 kg ha -1 ), medium in available (15.4 kg ha -1 ), high in available K (387.6 kg ha -1 ). Among the micronutrients Zinc (0.38 mg kg -1 ), Iron (4.60 mg kg -1 ) and Boron (0.39 mg kg -1 ) are in deficient range. The recommended dose of fertilizer was 80:60:30 kg NPK ha -1 . Sunflower variety PDKVSH-964 was used for the study. After land preparation, the sunflower seed was sown at 60 x 30 cm. The desired plant population was maintained uniformly by thinning as well as by gap filling. Five plants were randomly selected by moving diagonally in the net plot for growth and yield attributes. Yield was recorded at harvest. Economics was worked out on the basis of yield, cost of inputs and selling prices of crops at that time. Pre sowing, post-harvest soil samples and micronutrients contents and quality parameters were analysed from Department of Soil Science and Agril. Chemistry, Dr. PDKV, Akola. Plant biometric observation and plant nutrient status at harvest was taken. The yield was recorded and expressed in kg ha -1 . Nitrogen percentage in seed of sunflower was estimated by microkjeldahal method (Piper, 1966) [5] . The protein percentage of seed was estimated by multiplying nitrogen percentage by 6.25. The oil content in seed was estimated by Soxhlet method (Chapman et al., 1961) [6] . Analytical data of yield sample and computed data were subjected to statistical scrutiny as per the procedures given by Gomez et al. (1984) [7] . The treatment differences were worked out at five per cent probability level.

Results and Discussion

At the experimental site, this experiment was conducted in rabi season at Akola location with three consecutive years. The summarized results are presented below.

Seed yield

The data in respect of seed yield of individual year and pooled sunflower as influenced by foliar spray of chelated micronutrients in presented in table 1. It was evident from the data that, the application of RDF with 5 tons FYM + foliar application of Zn EDTA + Fe EDTA @ 0.25 % + FA of 0.2% Boron at 35 and 55 DAS (T 7 ) recorded significantly highest seed yield (2141 kg ha -1 ) followed by treatment T 6 (1887 kg ha -1 ). It was found due to the combine effect of GRDF and spraying chelated micronutrients Zn, Fe and Bo at 35 and 55 DAS as a synergistic effect. As regards to straw yield same trends are found. The Narayana Rao et al. (2020) [8] reported that seed yield of sunflower influenced by the foliar application of micronutrients. The Shete SA et.al. (2020) reported that application of micronutrients through foliar spray was found more beneficial than the soil application for oilseed crops. Padma et al., (2001) [9] concluded that, foliar spray of boron at 0.2% at ray floret stage in sunflower has recorded significantly higher seed set (84.2%), total number of seed per head (901), test weight (6.00g), seed yield (11.6 q ha -1

) as compared to control. Nzan Lotha et al. (2021) [10] reported that application of NPK +B (0.3%) +Zn @ (0.5%) will improve growth and yield of sunflower.

Stalk yield

The data in respect of stalk yield of sunflower as influenced by foliar spray of chelated micronutrients in presented in table 1. The significantly highest stalk yield of sunflower (4091 kg ha -1 ) was observed with the application of RDF with 5 tons FYM + foliar application of Zn EDTA + Fe EDTA @ 0.25 % + FA of 0.2% Boron at 35 and 55 DAS (T 7 ) followed by treatment T 6 (3689 kg ha -1 ). Micronutrients involved in increased auxin biosynthesis, IAA production and protein synthesis, which helps in promoting vegetative growth and ultimately the stalk yield. These results are in harmony with the research results of Swetha et al. (2020), Kumbhar et al. (2017) [3] and Narayana Rao et al. (2020) [8] reported that, the highest stalk yield of sunflower recorded in treatment with the foliar application of micronutrients.

Yield contributing characters

The data regarding the head diameter, number of seeds per head, 100 seed weight and volume weight are presented in table 2. From the results, it is revealed that, the highest head diameter, number of seeds per head, 100 seed weight and volume weight were recorded by the treatment RDF with 5 tons FYM + foliar application of Zn EDTA + Fe EDTA @ 0.25 % + FA of 0.2% Boron at 35 and 55 DAS (T 7 ) resulting highest head diameter (19.5 cm), No. of seed per head (1138), hundred seed weight (6.38 gm) and volume weight (40.1 gm). The foliar application of micronutrients particularly Boron (B), Zinc (Zn) and Iron (Fe) directly increases sunflower yield by improving seed setting, preventing chaffy seed and maximizing test weight. The Navale PS et al. (2025) [11] reported that, the highest number of filled seeds (888), seed yield -1 (48.1g) and other attributes. He reported that, Boron aids in the transport of sugars and carbohydrates from source (leaves) to sink (developing seed). While zinc enhances the chlorophyll synthesis, improving photosynthesis and energy supply for seed filling. Zinc and boron synergistically improve reproductive success, nutrient flow and metabolic function leading to significant increase in the number of filled seeds per plant in sunflower. These finding were in agreement with the conclusions of Hakale (2014) [12] .

Quality parameters

The data regarding protein content, protein yield, oil content and oil yield are presented in table 3 and4. From the data, it is revealed that, the highest protein content (18.6% ), protein yield (399 kg ha -1 ), oil content (38.0%) and oil yield (768 kg ha -1 ) are recorded by the treatment application of RDF with 5 tons FYM + foliar application of Zn EDTA + Fe EDTA @ 0.25 % + FA of 0.2% Boron at 35 and 55 DAS (T 7 ). However, it was found at par with treatment T 5 and T 6 . Micronutrients help in synthesis of amino acid, nitrogen metabolism, enzyme activation which is vital for protein formation in plants. This confirms the findings of Narayan Rao et al (2020) [8] reported that protein content was influenced by foliar application of micronutrients. The significantly lowest protein content (16.4%) was reported in absolute control. Oil yield improve due to sufficient nutrient supply ultimately nutrients involved in the formation of glycosides and activation of enzyme which aids to biochemical reaction in plant. Similar findings reported by Kumbhar et al., 2017 [3] showed that oil content of sunflower significantly improved with the soil and foliar application of micronutrients along with RDF. The significantly lowest oil content (30.4%) and oil yield (242 kg ha -1 ) by absolute control (T 1 ) It may be concluded that, application of GRDF (RDF 80:60:30 NPK kg ha -1 (P supplied through SSP) + 5-ton FYM/ha) + foliar application of Zn EDTA + Fe EDTA @ 0.25 % + FA of 0.2% Boron at 35 and 55 DAS recorded significantly highest seed and straw yield and all yield contributing characters of sunflower. The significantly highest protein content and yield and oil content and oil yield was recorded with treatment GRDF + FA of Zn EDTA + Fe EDTA @ 0.25 % + FA of 0.2% Boron at 35 and 55 DAS. Hence, for obtaining higher yield and quality up-gradation the, application of GRDF (80:60:30 NPK kg/ha + 5 tons FYM) with foliar application of Zinc EDTA 0.25 % (1.25 kg/ha), Fe EDTA 0.25% (1.25 kg/ha) along with 0.2 % Boron (1.00 kg/ha) respectively at 35 and 55 DAS is recommended.

References

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14. How to cite this article: Farkade B, Gahukar S, Gaikwad M, Fatak S. Effect of foliar application of chelated micronutrients on yield and quality of rabi sunflower (Helianthus annuus L.). International Journal of Research in Agronomy. 2026;9(10):269273. doi: https://www.doi.org/10.33545/2618060X.2026.v9.i10d. 6798