Differences in shoot regeneration response from cotyledonary node explants in Asiatic Vigna species support genomic grouping within subgenus Ceratotropis (Piper) Verdc.

Abstract

The efficiency of any plant regeneration system lies in part in its wide applicability to diverse genotypes. In Asiatic Vigna, cotyledon and cotyledonary node explants from 4-day-old seedlings of 27 genotypes were cultured in a medium consisting of MS salts, B5 vitamins, 3.0% sucrose and 1.0 mg l-1 BA. Direct and efficient multiple shoot regeneration (80-100%) from the cotyledonary nodes was obtained in all epigeal species namely radiata, mungo, aconitifolia, subspecies radiata var. sublobata, mungo var. silvestris and in the hypogeal but allotetraploid glabrescens. In contrast, two other hypogeal species V. angularis and V. umbellata failed to initiate shoots from the nodes. However, adventititious shoots developed at the basipetal cut (hypocotyl) in 35-67% of V. angularis explants. These results provide evidence in support of the existing genomic grouping within subgenus Ceratotropis, which designates AA, A1A1 and A1A1/- to epigeal, hypogeal and the allotetraploid species, respectively. Mean shoot production ranged from 3.3 to 10.4 shoots per explant during the first subculture and varied significantly among the responsive genotypes within 4 species. Additional shoots were obtained in all genotypes after subsequent subculture. However, cotyledons were not as regenerable as cotyledonary node explants. Although significant differences in rooting were observed among the shoots of the 15 genotypes, the response was generally higher in MS basal medium (MSO) than in MS with 1.0 mg l-1 IAA. Regenerated plants were successfully transferred to soil (50-100% survival rate) and all surviving plants were reproductively fertile.

Source or Periodical Title

Plant Cell, Tissue and Organ Culture

ISSN

1676857

Page

99-110

Document Type

Article

Subject

Cotyledonary node, Shoot regeneration, Species relationships, Subgenus Ceratotropis, Vigna

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