Genetic diversity has been revealed, using AFLP finger printing, in 37
accessions representing 21 species of Sesbania. The AFLP data has been
analyzed and distance trees, illustrating the relationships within and
among species, have been constructed using UPGMA and neighbor
joining (NJ) methods as implemented in the NTSYS-pc software. Both
trees illustrated polymorphism between accessions of the same species,
from different origins, but illustrated that intraspecific accessions have
closer genetic affinity to each other than to other species. The NJ and
UPGMA distance trees clearly delimited the species of the two subgenera
Agati and Daubentonia as two separate groups from those in subgenus
Sesbania. The AFLP data revealed considerable polymorphism among
species of subgenus Sesbania that is not correlated with karyotype
resemblances of species in this subgenus and their ability to cross. Based
on AFLP data this subgenus may be regarded the center from which
species in the other two subgenera have been derived. In the NJ tree S.
quadrata and S. rostrata are distinguished from two large groups, but in
the UPGMA tree S. quadrata is grouped with S. bispinosa and S.
cannabina, whereas S. rostrata is grouped with S. exaltata in one of the
NJ groups. The delimitation of species based on the analyses of AFLP
data is discussed in the light of their systematic delimitation.