Regeneration and analysis of genetic variability in wild sorghum, S. australiense Garber and Snyder

Abstract

In vitro techniques offer opportunity to broaden genetic variability by overcoming reproductive barriers between crop species. As an initial step for the exploitation of such techniques, we have established regeneration protocols for cultivated and wild sorghum species. The latter are important sources of insect resistance. The present study deals with immature inflorescence culture and cytogenetic stability of a wild Parasorghum species viz., S. australiense (2n=20). Regeneration was observed at high frequency (≥80%) on MS medium supplemented with kinetin (1.0 mg/l) and BAP (1.0 mg/l). Meiotic analysis of regenerants revealed somaclonal variation among regenerants from 12 month-old cultures. Chromosomal variations like aneuploids, hypodiploids, quadrivalent associations and tetraploids were found in the regenerated plants. RAPD analysis with PCR revealed polymorphism in these cytological variants. The protocol developed here might be used as a basis for achieving high frequency of regeneration and generating cytogenetic variants. Some of the variants might be useful in conventional breeding programs and for gene transfer studies from wild to cultivated species by somatic hybridization.