DNA methylation and genetic study of interspecific hybridization in Jatropha curcas L.

Genetic relationship among Jatropha curcas L., J. gossypifolia L., J. integerrima Jacq ., J. podagrica Hook., J. multifida L. and Ricinus communis L. was studied using 10 AFLP primer pairs. A total of 564 DNA bands were generated and used for cluster analysis. Using UPGMA method, R. communis was clearly separated from Jatropha spp, as well as separated the Jatropha spp. into two groups. The first group comprised of J. curcas , J. integerrima and J. podagrica , whereas the second group consisted of J. multifida and J. gossypifolia . The interspecific hybridization was carried out between J. curcas and other Jatropha species. The results showed that cross between J. curcas and J. integerrima was the most successful. However, some hybrids were also obtained from J. curcas x J. podagrica and J. curcas x J. multifida . The observed ratio of female and male flowers of hybrids from J. curcas and J. integerrima were 1:9.1 to 1:14.9 which fall between two parents. Percentage of methylation in all hybrid derived from J. curcas x J. integerrima was lower than that of the parents. Principal component analysis of methylation fingerprints revealed that the pattern of DNA methylation in all hybrids from J. curcas x J. integerrima was more similar to J. curcas than J. integerrima. Meiotic cells of the hybrids from J. curcas x J. integerrima, J. curcas x J. podagrica and J. curcas x J. multifida were also studied. Majority of the cells investigated were normal. However, some abnormal tetrads were observed in some cells of hybrids.