Identification of Prosopis juliflora and Prosopis - Universidad Pública ...

7presence or absence of each marker was scored in each accession and Nei’ssimilarity index (Nei and Li 1979) was applied to establish similarities. Thesimilarity values were used to cluster species using the unweighted pair groupmethod average (UPGMA) algorithm (Sneath and Sokal 1973).ResultsMolecular markers: section-specific, species-specific and complex-specificThe molecular markers obtained by PCR amplification that identified speciesbelonging to the section Algarobia, those that differentiated between P. julifloraand P. pallida and those that characterised the P. juliflora–pallida complexin this study are presented in Table 2. Twenty primers yielded profiles usefulfor classification of the accessions. Six primers: L02 (775) , L06 (800) , L09 (335) ,S03 (550) , S07 (1160) and R17 (1220) (Figure 1) produced molecular markers thatwere present in all the accessions analysed except P. cineraria. Thus, five newprimers were added to S07 (1160) , previously described by Ramı´rez et al. (1999)as a section-specific marker for section Algarobia. Assuming that theseamplification products are all derived from Prosopis species forming part of thesection Algarobia, it could be suggested that there are section-specific molecularmarkers.The markers L04 (325) ; P01 (550) ; P08 (730) ; P09 (570) ; P13 (1250) ; P14 (510) ;S07 (980) and S11 (460) were present in P. pallida seeds collected in Trujillo. Asthe amplification products in plant material collected in Piura, where P. julifloraand P. pallida are sympatric, are essentially identical to those present inmaterial from Trujillo, it may be concluded that the sample from Piura isP. pallida or a very closely related hybrid (Figure 2a). Seed from introducedpopulations presently identified as P. juliflora from Brazil, Cape Verde andSenegal, and seed collected in Brazil and classified as P. affinis Sprengel allshowed similar molecular profiles to‘ that amplified in DNA extracted fromseed collected in Trujillo and Piura. Thus, all of these accessions correspond toTable 2. Molecular markers found in the Prosopis samples.SectionP. juliflora–pallidaP. pallidaP. julifloraAlgarobiacomplex markersmarkersmarkersmarkersL02 (775) L01 (520) L04 (325) L04 (410)L06 (800) P01 (550) P08 (440)L09 (335) P08 (730) P12 (760)S03 (550) P09 (570) P12 (610)S07 (1160) P13 (1250) P14 (745)R17 (1220) P14 (510)S07 (980)S11 (460)