Screening of Edible Turmeric Cultivars for Resistance to Root-knot Nematode, Meloidogyne incognita

Abstract

Turmeric (Curcuma longa L.) is an economically important spice crop, but its production is constrained by root-knot nematodes, particularly Meloidogyne incognita. The use of resistant cultivars provides an eco-friendly and cost-effective approach to nematode management; however, cultivar-specific information on resistance remains limited. The study aimed to identify a source of resistance to the root-knot nematode, Meloidogyne incognita, among different turmeric cultivars. The experiment was conducted in the nursery of the Plantation Crop Garden, Biswanath College of Agriculture, AAU, Biswanath Chariali, Assam, during the kharif season of 2025 and was laid out in a completely randomised design. Plastic pots with a capacity of 2,000 cc were filled with a sterilised soil, sand and cow dung mixture in a 2:1:1 ratio. A single rhizome, bearing one or two healthy buds and weighing approximately 5 g, from each of the six turmeric cultivars was planted in an individual pot. The pots were arranged in a completely randomised design, with five replications per cultivar. One month after planting, each plant was inoculated with freshly hatched second-stage juveniles (J2) of Meloidogyne incognita at a density of 1 J2 per cc of soil. Two months following inoculation, the plants were carefully uprooted, and the numbers of galls and egg masses per root system were recorded. Average temperature, relative humidity and bright sunshine hours were recorded during the experimental period. Observations made two months after inoculation showed that the average number of galls per root system exceeded 31 in all the cultivars, viz., Tall Clone, Megha Turmeric, Black Turmeric, Lacadong, Local-1 and Local-2. Hence, the cultivars were categorised as susceptible based on the root-knot index. The root-knot index ranged from 3.4 to 4.0. From this experiment, it was concluded that none of the cultivars was resistant to the root-knot nematode. In the absence of resistant and moderately resistant cultivars, other eco-friendly nematode management methods may be adopted for the management of root-knot nematode in turmeric cultivation.