Karyomorphological and heterochromatin similarities among fourVigna species

Abstract

SummaryKaryomorphological similarities among four species of the genus Vigna, V. unguiculata, V. luteola, V. oblongifolia and V. vexillata, were evaluated. Two different approaches were followed: cytomorphometrical determinations, carried out with an automated image analysis system to improve resolution, yielded some karyotypical indices; the distribution of heterochromatin bands was interpreted using a recently reported algorithm.Both methods led to similar results: the most karyologically similar species to V unguiculata appears to be V. Iuteola, while V. obIongifolia appears to be the least related one.Abbreviations: B SG -barium-saline-Giemsa banding; CMA -chromomycin A3; H 33258 -bis-benzimid derivative Hoechst 33258; DAPI -4~,6-diamidino-2-phenylindol-dihydrochloride; TF% -total form; SYi -similarity index; Rec -resemblance between chromosomes

Cytotaxonomic studies inVigna.III. Chromosomal distribution and reacting properties of the heterochromatin in five wild species of the sectionVigna

“…Heterochromatin is classified on the basis of the reaction of each heterochromatin fraction to various differential staining techniques. The results are compared to those previously reported for other species of the same genus (GALAsso et al 1993;PIGNONE et al 1995b). …”

“…Vigna (MARECHAL et al 1978); we have analysed seven of them for general chromatin organization and karyobiological properties (GALASSO et al 1993;PIGNONE et al 1995b, and the present study). Unfortunately, many wild species described in the literature are only available as herbarium specimen: only few samples are obtainable as seeds in gene-banks or botanical gardens (PADULOSI 1990); in addition, often only one sample per species is available for distribution.…”

“…Heterochromatin determinations followed the method described by VENORA et al (1995b) with suitable modifications to conform to the different system in use.…”

“…Two different classes of heterochromatin with similar staining properties and chromosomal distribution were demonstrated (GALAsso et al 1993). Karyobiological characteristics of V. luteola and V. vexillata appeared more similar to those of cowpea, while V. oblongifolia appeared to possess a less related structure (PIGNONE et al 1995b;VENORA et al 1995a). These findings were unexpected since both V. luteola and V. oblongifolia, similarly to V. unguiculata, belong to the subgenus Vigna, while V. vexillata is supposed to have a more distant taxonomical position and included into the subgenus Plectotropis (MARECHAL et al 1978).…”