Production potential of Knol Khol (Brassica Oleracea L. var. Gongylodes) as influenced by zinc, boron and RDF levels under Patiala region

Introduction

Knol-khol (Brassica oleracea var. gongylodes) is a Cole crop valued for its nutritive knobs and wide adaptability. Still, its productivity is strongly limited by nutrient imbalances, particularly zinc and boron deficiencies. As a heavy-feeding Brassica, knol-khol removes large quantities of nutrients from the soil, making balanced fertilisation essential. (Alloway 2008) [1] . Among micronutrients, boron and zinc are the most critical, as they directly influence cell division, knob formation, pollen viability, carbohydrate metabolism, and overall yield quality. Boron plays a central role in meristem activity, membrane integrity, sugar translocation, and reproductive processes. (Shalini et al. 2002) [19] . In knol-khol, inadequate boron supply leads to physiological disorders such as knob cracking, brown heart, brittleness and malformed growth, severely reducing marketability. (Tiwari and Tiwari 2015) [20] . Zinc, on the other hand, regulates auxin synthesis, enzyme activation, protein formation, and photosynthesis. Its deficiency-common in nearly half of Indian soils-results in reduced knob diameter, poor vigour, and lower yields. (Biswas 2006) [3] . Because both nutrients interact synergistically with the recommended fertiliser dose (RDF), optimising their levels is essential to achieving maximum growth and quality. Despite the crop's economic and nutritional importance, limited research has examined how different levels of RDF, combined with zinc and boron, influence growth and yield parameters in knol-khol. This gap highlights the need for systematic evaluation of integrated nutrient management strategies to enhance productivity and improve knob quality under field conditions. (Kumari et al. 2025) [10] .

Methodology

The field experiment entitled "Production potential of knol khol (Brassica oleracea L. var. The site lies in the southeastern part of Punjab within the Indo-Gangetic plains and experiences a subtropical, semi-arid climate, characterised by hot and humid summers, a monsoon period, and cold winters. The soil of the experimental field is a well-drained alluvial soil, suitable for vegetable cultivation. This section outlines the experimental site, design, crop establishment, and treatment structure adopted for the study.

Experimental and treatment details

The study was conducted using a Randomised Block Design (RBD) comprising 13 treatments and replicated three times, resulting in 39 experimental plots. Plot dimensions and crop geometry were maintained uniformly across the field, where the gross plot size was 3.15 m × 2.00 m, the net plot size: [4] in knol-khol, Dhakad et al. (2024) [6] in cauliflower, Khatri et al. (2022) [8] in tomato, Kumar et al. (2020) [9] in brinjal, Pavithra and Subbarayappa (2023) [16] in knol-khol, Ningawale et al. (2019) [14] in cauliflower, Sen et al. (2025) [17] in cabbage and Meena et al. (2019) [12] in cauliflower. [2] in bitter gourd. Fresh and dry weight of knobs were also highest in T₁₃ (403.29 g fresh; 153.54 g dry). This improvement may be due to increased biomass accumulation and better nutrient storage in knobs.

Yield Parameters

Comparable results were documented by Faris et al. (2023) [7] and Dandhich S. (2013) [5] in knol-khol. Knob yield hectare per plot showed a marked increase under T₁₃ (172.90 q ha⁻¹), whereas the lowest yield was recorded in the control. The enhanced yield is attributed to balanced macro and micronutrient supply, which improves enzyme activation, protein synthesis and knob development. These results corroborate the findings of Kumari et al. (2025) [10] , Naik et al. (2025) [13] and Manhar et al. (2023) [11] in knol-khol. [15] , Faris et al. (2023) [7] and Shah et al. (2010) [18] in knol-khol. The combined application of zinc, boron, and the full recommended dose of fertilisers produced the most favourable outcomes, with T₁₃ (100% RDF + 5 kg Zn ha⁻¹ + 1 kg B ha⁻¹) consistently outperforming all other treatments.

Conclusion

From the present study, it can be concluded that the combined application of zinc, boron and RDF levels of fertilisers produced the most favourable outcomes, found in treatment T₁₃ (100% RDF + 5 kg Zn ha⁻¹ + 1 kg B ha⁻¹), which is outperforming significantly as compared to all other treatments. An integrated nutrient approach enhances growth, yield, quality, and economic returns by improving both nutrient availability and physiological efficiency in knol-khol. Their synergistic interaction promoted superior knob development and improved marketable quality.

References

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