Knol-Khol: Cultivation and Varieties

Introduction

• Knol-Khol is a cool-season crop with an edible stem and knob.
• The knob is a thickened tissue above the cotyledons.
• Its origin is in the Mediterranean region, and it is commonly grown in West Europe, North America, Japan, and India.

Taxonomy

• Knol-Khol is classified as Brassica oleracea var. gongylodes belonging to the Brassicaceae family.

Nutritive Value

• Knol-Khol offers a range of nutrients including protein, carbohydrates, fat, calcium, iron, magnesium, potassium, vitamins C and E, riboflavin, and thiamine.

Varieties

• Various varieties include Early White Vienna, Early Purple Vienna, White Vienna, Purple Vienna, King of North, Large Green, and Palam Tender Knob.
• Each variety has specific features including growing time, size, and color of the knob.

Area and Distribution

• Knol-Khol's cultivation is not widespread, mostly found in the Mediterranean region, West Europe, North America, Japan, and India.
• In India, it is primarily grown in states such as Jammu & Kashmir, West Bengal, Uttar Pradesh, Himachal Pradesh, and Madhya Pradesh.

Climate

• Knol-Khol thrives in cool climates and can tolerate frost and cold temperatures.
• Seeds germinate best at 15° to 20°C.

Soil and Field Preparation

• Suitable soils are sandy loam and clay loam with a pH of 5.5 to 6.8.
• Proper field preparation involves 5-6 ploughings for good tilth.

Manures and Fertilizers

• The recommended application includes 200 Q/Ha of FYM and 100 kg/Ha of nitrogen, 85 kg/Ha of phosphorus, and 170 kg/Ha of potassium.
• FYM is applied 4-6 weeks before transplanting.

Seed Rate and Treatment

• The seed rate for one hectare is 1-1.5 kg.
• Seed treatment involves using Thiram (2g) and Captan (2g).

Raising of Nursery

• Prepare a nursery bed of 3m x 1m, 15 cm high from the ground.
• Sow seeds 1 cm deep, and spray Thiodon (1.8 ml in 1 liter of water) 10 days after germination.
• Use a 0.2% Captan solution to prevent damping off.

Transplanting

• Transplant 3-4 weeks old seedlings, preferably in September or October in North India.

Spacing

• Early season varieties: 30 x 20 cm.
• Late season varieties: 45 x 30 cm.

Irrigation

• Irrigation is crucial, starting immediately after transplanting.
• Irrigate every 15 days, avoiding heavy irrigation as it can crack the tubers.

Intercultural Operations and Weed Control

• Hoeing and weeding are required after each irrigation.
• Earthing up is done 25-30 days after transplanting.
• Pre-transplant application of Treflan (Trifluralin @ 0.5 litre/Ha) and Semeron (Desmetrayne @ 1kg/Ha) controls weeds.

Harvesting

• Harvest when the swollen stem reaches 5-8 cm in diameter.
• Harvest before the tuber matures.
• Harvest 2-3 times a week using a sharp knife or sickle.

Yield

• Early season variety: 125 to 175 Q/Ha.
• Late season variety: 200 to 250 Q/Ha.

Insect Pests

• Diamond Back Moth (Plutella xylostella L.)
  • Caterpillars feed on leaves, leaving holes.
  • Control: Thiodone 35 EC (0.03%) repeated every 10 days.
• Aphids (Brevicoryne brassicae)
  • Aphids suck sap from leaves, hindering plant growth.
  • Control: Spray Malathion (0.1%), Monocrotophos (0.03%), or Endosulfan (0.05%).
• Cutworms (Agrotis ipsilon)
  • Cutworms chew foliage and cut stems at ground level.
  • Control: Malathion (25 kg/Ha).

Diseases

• Damping Off (Pythium aphanidermatum)
  • This soil-borne disease causes seedlings to rot and fall over.
  • Control: Spray Carbendazin (1g) and Benomil (1g).
• Downy Mildew (Peronospora sparsa)
  • Leaves have light green to yellow spots on the upper surface.
  • Control: Apply Mancozeb (0.25).

This quiz explores the cool-season crop Knol-Khol, including its origin, taxonomy, and nutritious value. You will learn about the various varieties of Knol-Khol and their specific features. Test your knowledge on the cultivation areas and distribution of this unique vegetable.