Breeding and biotechnology of Jatropha curcas

Abstract

The growing demand for renewable energy sources will increase the demand for oilseeds in Brazil and worldwide. This demand will only be supplied if plant varieties with exceptional agronomic and chemical traits are developed. This process can be accelerated by application of biotechnology and molecular biology techniques, as we have done in the case of Jatropha curcas, a perennial oilseed. We have used two strategies: (1) Exploitation of pre-existing variability in the germplasm of J. curcas evaluated through morphological, molecular and chemical markers (such as fatty acid and phorbol esters content). We also investigated self-fertilization with selected genotypes to analyze the effects of inbreeding, particularly with regard to the production of non-toxic, smaller, male-sterile and gynoic plants; and (2) Increase the genetic variability through interspecific hybridization and biotechnology. Despite the post-zygotic incompatibility encountered in most interspecific crosses, the use of artificial hybridization coupled with tissue culture techniques, such as in vitro embryo rescue and subsequent multiplication via somatic embryogenesis has yielded unprecedented results in the form of rare hybrids between J. curcas and other species of this genus. So far, we have obtained more than 80 F1 hybrids and 140 BC1 × F1 backcross progenies. Evaluation of these hybrids and the continuation of this line of research will greatly expand the germplasm bank of Instituto Agronômico de Capinas (IAC) and should contribute significantly to rapid production and release of new improved cultivars. In addition to their application in assessing genetic variability, molecular markers were useful to confirm F1 hybrids and BC1 generations by excluding the possibility of apomixis and to select suitable plants for genetic breeding.