Effect of plant growth regulators on growth, yield and quality of cabbage (Brassica oleracea var. Capitata)

Introduction

Cabbage (Brassica oleracea var. capitata) is one of the most important cole vegetable crops belonging to the family Brassicaceae. It is widely cultivated throughout India due to its nutritional value, adaptability, and economic importance. Cabbage is rich in vitamins A, B, and C, minerals, proteins, carbohydrates and antioxidants. It is consumed both as cooked and raw vegetable in salads and various culinary preparations. Plant growth regulators (PGRs) play a vital role in regulating physiological and biochemical activities in plants. Among different PGRs, gibberellic acid (GA₃) and naphthalene acetic acid (NAA) are extensively used for improving vegetative growth, head formation, yield and quality in vegetable crops. GA₃ promotes cell elongation, stem growth and leaf expansion, whereas NAA enhances root development, nutrient absorption and overall plant growth. The balanced application of plant growth regulators can significantly improve cabbage productivity by enhancing photosynthesis, nutrient translocation, and metabolic activities. Therefore, the present investigation was undertaken to evaluate the effect of different concentrations of GA₃ and NAA on growth, yield and quality of cabbage under Kanpur conditions.

Materials and Methods

The present investigation was conducted during 2025-2026 at the Agriculture Research Farm, Rama University, Mandhana, Kanpur (U.P.), India. The experimental soil was sandy loam in texture with good drainage facilities.The experiment was laid out in Randomized Block Design (RBD) with three replications. The cabbage variety used in the experiment was Pride of India. Nine treatments consisting of different concentrations of GA₃ and NAA were evaluated. The treatments were:-T₀ -Control, T₁ -GA₃ @ 50 ppm (foliar spray at 30 DAT),T₂ -GA₃ @ 75 ppm (foliar spray at 30 DAT),T₃ -GA₃ @ 100 ppm (foliar spray at 30 DAT),T₄ -GA₃ @ 125 ppm (foliar spray at 30 DAT),T₅ -NAA @ 50 ppm (foliar spray at 30 DAT),T₆ -NAA @ 75 ppm (foliar spray at 30 DAT),T₇ -NAA @ 100 ppm (foliar spray at 30 DAT),T₈ -NAA @ 125 ppm (foliar spray at 30 DAT) Plant Height Significant differences among treatments were observed for plant height at 45 and 60 days after transplanting. The maximum plant height at 45 days (30.54 cm) and 60 days (34.38 cm) was recorded in T₇ (NAA @ 100 ppm), followed by T₄ and T₈. The minimum plant height was recorded in control treatment (T₀).The increased plant height under NAA treatment might be due to enhanced cell elongation, increased nutrient uptake and stimulation of physiological activities. Similar findings were reported by several researchers in cabbage and other cole crops.

Number of Leaves per Plant

The highest number of leaves per plant at 45 DAT (13.68) and 60 DAT (17.84) was observed in T₇ (NAA @ 100 ppm), while the lowest number of leaves was recorded in control. Enhanced vegetative growth under NAA might be attributed to increased photosynthetic activity and better nutrient utilization.

Leaf Length and Width

The maximum leaf length (28.34 cm) and leaf width (20.54 cm) were recorded in T₇, followed by T₄ and T₈. The minimum values were observed under control treatment. The application of NAA improved vegetative growth due to enhanced metabolic activities and cell enlargement.

Plant Spread: The maximum plant spread (45.78 cm) was recorded in T₇ followed by T₄ (45.52 cm). The minimum plant spread (42.01 cm) was observed in control treatment.

Increased plant spread may be due to vigorous vegetative growth promoted by NAA application.

Yield Parameters

Days to Head Initiation and Maturity

The earliest head initiation (42.54 days) and head maturity (68.54 days) were recorded in T₇. Early head formation under NAA treatment may be attributed to enhanced physiological efficiency and accelerated growth processes.

Diameter of Head and Stalk Length

The maximum head diameter (11.54 cm) and stalk length (5.98 cm) were recorded under T₇. Better head development under NAA treatment might be due to increased carbohydrate accumulation and nutrient translocation.

Average Head Weight and Yield

The highest average head weight (1.78 kg) and yield per hectare (5.70 t ha⁻¹) were recorded in T₇, followed by T₄ and T₈. The minimum yield was recorded in control. The higher yield under T₇ may be attributed to increased vegetative growth, larger head size, and enhanced photosynthetic activity.

Quality Parameter TSS (°Brix)

The highest TSS (7.54 °Brix) was recorded in T₇ followed by T₄ (7.32 °Brix). The minimum TSS (6.26 °Brix) was recorded in control. Increased TSS indicates improved quality and accumulation of soluble solids due to better metabolic activities.

Economics:

The maximum benefit-cost ratio (2.12) was recorded in T₇, followed by T₄ (1.96). The minimum B:C ratio (1.02) was observed in control treatment. The higher economic return under T₇ was mainly due to increased yield and improved quality.

References

1. Bose TK, Som MG, Kabir J. Vegetable Crops. Kolkata: Naya Udyog; 2002.
2. Choudhury B. Vegetables. New Delhi: National Book Trust; 1996.
3. Kumar S, Sharma RR. Effect of plant growth regulators on growth and yield of cabbage. Vegetable Science. 2010;37(2):142-145.
4. Singh AK, Singh VB, Singh RK. Influence of GA₃ and NAA on growth and yield of cabbage. Indian Journal of Horticulture. 2012;69(3):413-416.
5. Yadav RK, Patel PK, Singh HK. Effect of plant growth regulators on growth and yield of cabbage. International Journal of Agricultural Sciences. 2015;11(2):240-244.
6. Thapa U, Rai R, Prasad VM. Influence of plant growth regulators on vegetative growth and yield of cabbage. Asian Journal of Horticulture. 2013;8(1):123-126.
7. Taiz L, Zeiger E. Plant Physiology. USA: Sinauer Associates Inc.; 2010.
8. Pandey SN, Sinha BK. Plant Physiology. New Delhi: Vikas Publishing House Pvt. Ltd.; 2006.