Utilization and conservation of Euryale ferox Salisbury in Mathila (North Bihar), India

Abstract

Euryale ferox Salisbury, locally known as makhana, is the main aquatic cash crop of Mithila (North Bihar), India. Thousands of natural and man-made waterbodies of this region are ideal reservoirs for combined fish and makhana cultivation which is a major source of livelihood for fishermen. E. ferox is an important ingredient of Hindu ritualistic oblations despite the fact that it finds no mention in old Sanskrit scriptures. The plant is unusual in having both cleistogamous and chasmogamous flowers. The seeds are edible and very nutritious. The expenditure incurred over its cultivation is modest as the seeds left over after harvest germinate the next season. The only labour involves some thinning out of overgrowths, transplanting into sparse areas, the collection of dispersed seeds from the pond bed during harvest and their preparation for sale. Calorific values of the edible seeds correspond well with most staple food materials including wheat, rice and other carbohydrate-rich cereals. Despite its low protein percentage (10–12%), it is superior to most plant- and animal-based diets as evidenced by its high essential amino acid index (89–93%) and arginine+lysine/proline ratio (4.74–7.6). According to traditional systems of Indian medicine E. ferox possesses medicinal properties against a number of human ailments involving respiratory, circulatory, digestive, renal and reproductive systems. Small starch grain dimensions (1–3 μm) make it effective against digestive disorders. Early tender leaves of the crop require protection from the leaf-rolling larval pests of Nymphula crisonalis Walker as well as aphids identified as Rhopalosiphum nymphaeae Linnaeus which can damage the crop in epiphytotic proportions. Roots also are heavily damaged by Donacia sp. A thrips known as Frankliniella intonsa Trybom damages the flowers, while Bagous vicinus Hustache, a weevil, destroys fruits by making holes in the pods. Synchytrium sp., a phycomycetous fungus, produces galls on its mature leaves. Tyrophagus putrescientiae Schrank, a mite, damages the stored seeds. Two beetles, Menochilus sexmaculata Fabricius and Scymnus sp. have been identified as predators attacking nymphs and adults of R. nymphaeae. The identity of a number of other insect associations has yet to be established. E. ferox has become extinct in the temperate lakes of Kashmir and has become rare in the contemporaneous flora of Eurasia. Major parts of the flood-ravaged north-eastern districts of North Bihar have witnessed a virtual root-out of the crop on account of sand filling of the beds of water bodies.