Apomixis as a tool for development of high yielding clones and selections in Jatropha curcas L.

Abstract

Jatropha curcas L. has gained attention as an ideal feedstock for biofuel production. One of the major limitations for profitable cultivation of the crop is the lack of high yielding cultivars with predictable yields. This study describes the exploitation of the mixed mating system including apomixis prevailing in the crop for development of high yielding genotypes. Evaluation of 135 accessions (AC) originating from 15 countries showed apomictic mode of seed development in 33 accessions. Based on the apomictic behavior, crosses were effected between a non-toxic high yielding genotype of Mexican origin (AC-2) and an Indian toxic genotype with synchronous maturity (AC-86). The F1 exhibited high heterosis and continued to produce seeds through both apomixis and sexual reproduction. The F1A1 progeny (n = 94) derived from the F1 hybrid through apomixis were productive with mean seed yield of 335, 586 and 644 g/plant during the 1st, 2nd and 3rd years after planting. The F1A1 progeny continued to reproduce through apomixis which ranged from 9.3 to 88.3%. A dendrogram based on genetic distances obtained from 1172 single nucleotide polymorphisms of 11 apomictic progenies along with the parents and the F1 hybrid unequivocally established the maternal origin of the apomictic plants. Microscopic analysis of developing apomictic ovules showed adventitious embryos. This study demonstrates the possibility of development of high yielding cultivars in a short time frame and in a cost effective manner by combining different mating systems prevalent in the crop viz, hybridization of diverse parents, vegetative propagation of high yielding hybrids through cuttings, and perpetuation of the superior recombinants through apomixis.