Molecular evidence for natural interspecific hybridization in Prosopis

Interspecific hybridization can occur under natural conditions among species of the Prosopis genus, potentially giving rise to hybrid individuals with increased adaptation values. A study was conducted to assess the occurrence of interspecific hybridization among Prosopis in the Argentinian Chaco region and the species involved. The survey included seven hybrid individuals and their potential parents. Principal component analysis (PCA) was carried out based on 16 morphological characters. The molecular marker study was carried out by the comparison of RAPD patterns of amplification using six primers. A total of 91 RAPD fragments were analysed, yielding 33 species-specific markers, 24 bands that were common to two or three parental lines, and 22 bands of unknown origin. The dendrograms arising from Nei’s genetic distances derived from the molecular data showed a clustering pattern in agreement with the grouping obtained by the PCA of the morphological traits. The results demonstrate the occurrence of interspecific hybridization involving Prosopis alba, P. nigra and P. hassleri in the Argentinian Chaco.