Phyllogeography of native and invasive Hieracium spp. (Asteraceae) herbs from southern Argentina and Chile, implications for management.

BRAUN, K.; MIROL, E.; COLLANTES,M.B.; PIGNATARO, G.; SIMÓN, P.; OLIVA, G.; GOÑI, L.; HUMANO, G.; WULFF, A.; MANSILLA, H.; CORTES, T.; CIPRIOTTI, P.A.; HOULISTON, G; DETTORI, S.

Bariloche, Argentina

Congreso; VI Southern Connection Congress. Gondwana Reunida: Una Perspectiva; 2010

Hieracium spp. weeds have invaded several gondwanic countries, producing severe ecological and economical damage. To explore hybridization, geographic races, and genetic variability of Hieracium spp. species from southern Argentina and Chile,we sequenced 650 base pairs of the nuclear ribosomal DNA ITS sites from 53 individuals belonging to invaders H. pilosella (n=31) and H. praealtum (n=14), and to natives H. cff. patagonicum (n= 3) and H. chilensis (n=5), and we included secuences from New Zealand and from the gene bank (natives H. antarcticum, and H. patagonicum). Different phylogenetic trees showed a well supported clade including the exotic species as sister groups, and another clade for all native species. H. cff. patagonicum (a species attacked by an insect candidate for biocontrol of exotic Hieracium species) individuals had the exact same sequence as four of the individuals of H. praealtum. Though a wide latitudinal range was studied, intraspecific genetic distances were very low (H. pilosella and H. praealtum: 0.0024, H. chilensis: 0.0032) and genotypes differed by only one mutation. There was no geographic structure in any of the examined species, suggesting asexual-apomictic reproduction, a low mutation rate, and no hybridization among species, and encouraging the use of biological control to manage these invasions, an effective-in-the long-term and environmentally friendly method.