Tech frees ‘kalmi saag’ of toxins, raises yield

Lucknow: Locally known as ‘Karemua' or ‘Kalmi Saag', water spinach has always thrived in ponds, reservoirs and waterlogged areas, often growing submerged in water, making it difficult to harvest. Being abundant in these waterlogged habitats made its nutritional value inconsistent, with leaves sometimes absorbing undesirable or harmful substances from stagnant waters.Recognising this challenge, scientists at ICAR – Indian Institute of Vegetable Research (ICAR-IIVR), Varanasi, took up a mission to ‘domesticate' this ancient vegetable, said Dr Rajesh Kumar, director, ICAR-IIVR. "Through research and innovative cultivation techniques, IIVR developed and released the first public sector variety, Kashi Manu, a technology that allows water spinach to be grown in upland fields, just like conventional leafy vegetables," he said.The breakthrough transformed ‘Kalmi Saag' from a niche aquatic plant into a high-yielding, commercially viable, and year-round crop. The variety stands out for its nutritional richness, as it has an impressive profile of minerals, vitamins, and dietary fibre. Kashi Manu provides carbohydrates (3.14 g), calcium (141.92 mg), iron (59.67 mg), magnesium (462.22 mg), zinc (1.59 mg), energy (19.0 Kcal), dietary fibre (2.19 g), and Vitamin A (6300 IU) per 100 grams of edible portion.Besides, its low soluble oxalate content (79.2 mg/100g Fresh Weight), compared to other leafy vegetables, makes it remarkable. High oxalate content can lead to stone formation in the body. Cooking its leaves further reduces soluble oxalates by 35–40%, enhancing both safety and nutritional quality.Being climate-resilient, it grows throughout the year, tolerating extreme temperatures, exceeding even 45°C. Cultivation of the variety has been standardised to ensure high yields and sustainable production, said Dr Rakesh K Dubey, principal scientist and developer of the variety."Seeds are sown in rows with spacing of 20 cm between lines and 10 cm between seeds, requiring 20–25 kg of seeds per hectare. Leafy biomass can be harvested by cutting 2.5 cm above the ground, allowing the plant to regenerate continuously. With proper management, the crop can yield over 100 tons of fresh leafy biomass per hectare," he said.The harvested leaves are sold at Rs 30 to Rs 40 per kg. Its cultivation has been demonstrated in many places across the country. Over 1,000 families have been given seeds for kitchen gardens and rooftop cultivation. Its suitability for organic and natural farming systems, adaptability, high yield, low cultivation cost and nutritional superiority make it an ideal crop for entrepreneurial opportunities among farmers.