Identification of male-specific marker and development of rapid Loop-mediated isothermal amplification assay for sex identification in Indian major carp Labeo rohita

Freshwater aquaculture in India mainly relies on three Indian major carps, with rohu (Labeo rohita) being the most important species in polyculture systems. Quality hatchery seed production plays a vital role in enhancing aquaculture production. However, unorganised and poorly managed broodstock in hatcheries affect the seed quality leading to economic losses for farmers. These challenges can be tackled through the establishment ofscientifically managed brooders. Developing an optimal female-to-male ratio for brooders requires maintenance of a large number of individuals for an entire year, as sex can only be determined at the maturity stage only. To address this issue, the current study developed a molecular marker and a Loop Mediated Isothermal Amplification (LAMP) assay for early gender determination, enabling the identification of the gender of rohu, even at the fingerling stage. This marker would enable the hatchery professionals and farmers to maintain an optimal male-to-female ratio from the early stage, leading to better broodstock management, reduced inbreeding and enhanced seed quality and quantity, which would ultimately benefit the aquaculture industry and promote sustainable fish farming practices in India Keywords: Early gender determination, LAMP, Quality hatchery seed, Rohu, Sex-specific marker