An update on biological advancement of Jatropha curcas L.: New insight and challenges

Sustainable production of non-food oleaginous crops is highly desirable towards meeting increasing global demands for energy by supplementing the diminishing supply of fossil fuels without affecting food security. Jatropha curcas L., a high yielding oleaginous seed crop (30-48% oil), with a simple propagation system, short gestation period and high adaptability to a wide range of climatic and edaphic conditions, qualifies to be a potential candidate for sustainable biofuel production. The crop has been proposed as part of the solution to the challenges of climate change, energy scarcity and provision of rural income, as it can grow in marginal soils with minimal nutrient content. However, in 2010, this view was challenged due to unpredictable yield patterns of the crop, recorded for plantation in marginal and low nutrient environments. The main reason behind the failure to meet its promise, was the paucity of information of the optimal agricultural practices and nutrient requirements required for large scale cultivation of J. curcas. The low productivity of seed in J. curcas was identified to result from a combination of variation in seed quality and quantity, high male to female flower ratio, asynchronous flowering, seed toxicity and susceptibility to various biotic and abiotic stresses. With the advancement of new technology and the availability of a whole genome sequence for J. curcas, several studies addressed at overcoming the shortcomings of the plant via biological approaches have been reported, indicating a renewed promise for this energy crop. This review addresses recent developments in improvement of J. curcas from the biological perspective, identifies some remaining gaps in knowledge and provides recommendations for future studies towards economically viable J. curcas cultivation.