“…PTM appears to have spread since, being noted in Australia in 1977 ( Khan and Tekauz, 1982 ) and in Montana, United States in 1981 ( Bockelman et al, 1983 ). Although artificial hybrids can be readily made in the laboratory ( McDonald, 1967 ; Smedegård-Petersen, 1977a ; Campbell and Crous, 2003 ; Jalli, 2011 ), PTT and PTM are considered to be genetically autonomous populations ( Rau et al, 2003 , 2007 ; Bakonyi and Justesen, 2007 ; Bogacki et al, 2010 ; Lehmensiek et al, 2010 ; Leišová-Svobodová et al, 2014 ; Akhavan et al, 2016 ). Natural hybrids appear to be rare and have been suggested by RAPD and AFLP studies ( Campbell et al, 2002 ; Leišova et al, 2005 ; McLean et al, 2014 ), and recently confirmed by Poudel et al (2017) using form-specific markers.…”