In what can act as a boon to farmers growing watermelon across India, the scientists of Vegetable Science department at the Indian Institute of Horticulture Research (IIHR) have developed a new and hybrid root stock called Arka Shakti. This root stock is resistant to Gummy Stem Blight (GSB), a fungal disease that is mostly seen in watermelon.
Earlier, IIHR had developed two new varieties of watermelon — Arka Manik and Arka Shyama — through their watermelon improvement programme. Now, scientists have introduced a hybrid root stock, Arka Shakti, that can be used to grow existing varieties of watermelon without any fungal diseases.
Sreenivasa Rao, Principal Scientist, Vegetable Science department, IIHR, said, “According to data from the Horticulture Department in Karnataka, the area under watermelon cultivation was 12,000 hectares in 2014, and had reduced to 1,300 hectares in 2024. Farmers in Chamarajanagar, Mandya, Bidar, and Kalaburagi districts grow watermelon. The reason behind the drastic decrease in the area of cultivation is susceptibility of watermelon to GSB disease.”
Professor Rao added, “Farmers get to know of the disease in watermelons only during the harvest as it doesn’t show up earlier. GSB is caused by a fungal pathogen Stagonosporopsis cucurbitacearum, and, in most cases, occurs along with Fusarium, another fungal disease. This disease spreads through seed, soil, and air simultaneously. While seed and aerial infection can be managed by chemical management, soil infection is difficult to manage. Using resistant root stocks is a good option to overcome this problem.”
The scientists noted that soil develops infection when watermelon is cultivated in the same soil without any crop rotation for a long time.
Development of Arka Shakti
Arka Shakti, a root stock hybrid, is an interspecific cross between Citrullus amarus and Citrullus lanatus, and is tolerant to fungal diseases.
He explained, “When we develop a new root stock resistant to diseases, we must ensure to use the same genus. For instance, watermelon belongs to the genus of Citrullus, and Citrullus amarus also belongs to the same genus. It is also a wild species, which is less prone to disease. Farmers can bring whichever variety of watermelon seeds they buy from the market and graft it with Arka Shakti root stock. Once grafting is done, tiny plants are kept in a chamber maintaining required temperature and light. Later, the plants are moved to the fields to grow watermelon.”
Cost of cultivation using Arka Shakti
The entire process of grafting and growing plants before moving them to the fields can be done with the help of nurseries as they have the required facilities and skilled labour to graft them, he said.
He said, “Nurseries charge ₹6 to ₹8 for each plant. If a farmer is currently investing ₹60,000 to cultivate watermelon in one acre land, he earns ₹2.5 lakh per acre after harvesting and selling. If grafted using Arka Shakti root stock, farmers will incur ₹15,000 extra, which is ₹ 75,000 per acre. However, the watermelons will be disease free and the profits might also increase because of good quality and quantity.”
Mr. Prof. Rao said that IIHR has cultivated a small quantity of watermelons using Arka Shakti root stock. “The colour of the watermelon is good, unlike the faded ones available in the market. Tastewise also, the fruit is sweet, and each fruit is 2 to 3 kg more than a usual watermelon. It weighs between 3 to 8 kg depending on the variety,” he said.
Reach farmers via nurseries
Since it is not possible for IIHR to introduce Arka Shakti commercially in a large market to farmers, they want to train nurseries from across India that are interested to learn the technique.
He said, “This new root stock can reach farmers through nurseries, which is a win-win situation. Nurseries can generate revenue while farmers can expect a good yield along with profits.”
Published – September 30, 2026 04:51 pm IST
