Interspecific hybridization in the genus Jatropha

Abstract

Jatropha curcas L. has assumed importance in tropical and subtropical countries as a potential biofuel crop. The limitations with the currently used germplasm are the lack of knowledge of the genetic base, poor yields, low genetic diversity and vulnerability to a wide array of insect pests and diseases under monoculture. Few varieties are reported in different countries but the cultivars are a result of selection from locally available ‘wild’ material. The crop has not been domesticated so far and there is an urgent need to initiate systematic breeding programmes for developing elite genotypes in order to transform the low yielding wild J. curcas into a high yielding cultivable crop. Assessment of genetic diversity in J. curcas germplasm indicated modest levels of variability for various agronomically desirable traits. However, vast scope exists for genetic improvement of the crop through alien gene transfer via interspecific hybridization. Hybridizations between sexually compatible species facilitates introgression of desirable genes for characters, such as, high oil content, oil quality, resistance to insect pests and diseases, reduced toxicity of endosperm proteins and improved growth on problematic sites. With a modest estimate of 6–8 years of research programme and the involvement of both national and international organizations in the activities on assemblage and evaluation of germplasm including wild species, identification of divergent material, interspecific hybridization, selection and generation advancement, development of molecular tools and genetic map of the crop, besides improved germplasm with desirable attributes can be accomplished.