Isozyme inheritance and variation of phosphoglucoisomerase (PGI) were
investigated for six genera of 'true citrus fruit trees' (Rutaceae) an
d their intergeneric hybrids. The progeny segregated showing Mendelian
inheritance at locus Pgi-1 in Fortunella, Eremocitrus and Microcitrus
. Some common isozymes were detected among the six genera. These resul
ts suggest that a genetic relationship exists among all the genera of
the 'true citrus fruit trees' group.