Conservation status and utilization of Caralluma edulis: an important threatened medicinal plant species of the Thar Desert, India

Caralluma edulis locally known as "Pimpa", is an important food-cum-medicinal plant of the extreme arid regions of the Thar Desert. It is a drought resistant stem succulent occurring in dry sandy places in hot arid areas preferably within the large tussocks of Murath grass (Panicum turgidum). Traditionally, its succulent stems are consumed raw as greens, vegetable and is also used as medicinal plant of the Thar Desert of India. Degradation of rangelands due to high grazing pressure and changes in land use pattern has threatened its existence. This study was therefore, taken up to identify the sites for in-situ conservation of C. edulis through field survey in Jaisalmer district and also to characterise/evaluate the collected germplasm ex-situ for its sustainable utilization in future. The issues related to both in and ex situ conservation were also investigated. Field surveys conducted in Jaisalmer in arid part of the Thar Desert in India during August to October for two consecutive years (2012 and 2013) revealed its occurrence in patches in villages such as Khuyiyala, Bahramsar dham, Deva-II and Chandan. Germplasm of C. edulis by means of rooted-stems collected from above sites was planted in nursery at Central Arid Zone Research Institute, Regional Research Station, Jaisalmer. Data were recorded on its growth, reproductive behaviour and germination. Initial and final germination of seeds of C. edulis (collected from plants raised by rooted-stems of Chandan area) recorded in nursery as 32.1 and 87.5 % on 4th and 6th days after sowing, respectively. The statistical analysis of characters under study revealed the presence of high co-efficient of variation (CV in %) in number of branches per plant (51.71) followed by number of pod (in pair) per plant (49.41) and least in collar diameter (10.05). The range and mean values of some important characters are as follows: plant height (38.0-62.0 and 50.7 cm), number of branches per plant (1.0-10.0 and 3.9), number of flowers per plant (2.0-7.0 and 4.8), number of seeds per pod (15.0-30.0 and 20.8) and seed length (4.9-8.7 and 7.0 mm), respectively. As it flowered and set seeds at nursery in our study, it has opened avenues for large scale multiplication and future cultivation of the species. These findings along with its economic importance are detailed in this paper.