SEM STUDIES OF SEED COAT IN SOME ASIATIC VIGNA SPECIES AND THEIR TAXONOMIC AND PHYLOGENETIC SIGNIFICANCE

Abstract

Seed morphology, hilum structure and cellular structure of seed coat
of predominently cultivated and wild species of the genus Vigna in India
were studied using scanning electron microscopy (SEM). The important
species include mung bean Nigna radiata (L) Wilczek), urid bean N.
mungo (L.) Hepper), rice bean N, umbellata (Thunb.) Ohwi and
Ohashi), moth bean N. aconitifolia (Jacq.> Marechal) and Pillipasera
N. trilobata Ail.> and their' wild occurring closely related putative
progenator forms particularly V. radiata (L.) var. sublobata Verde.,
V. mungo (L.) var. silvestris Lukoki, Marechal and Otoul, wild form~
of -v. umbellata and V. aconitifolia. Seed coat cellular structure
and hilium were characteristic to each species and appeared to be
species-specific. ConSiderable morphological similarties were observed
between cultivated plants of V. radiata with its related wild species
V. radiata var. sublobata, V. mungo with that of V. mungo var.
silvestris and V. umbellata with its wild form. In V. aconitifolia,
cultivated and wild types differed drastically in their seed coat surface
pattern. SEM seed coat structure was found to be useful in establishing
taxonomic a1"d phylogenetic relationship in these Indian species of
Vigna