Assessment of genetic purity of micropropagated plants of sugarcane by isozyme and RAPD analysis

Abstract

Shoot tip expiants of nine sugarcane varieties(Saccharum species hybrid.), CoLk 8102, CoLk 8001, CoS 767, CoLk 9606, CoLk 9617, CoS 95255, BO 91, CoJ 64 and Co 1148, were established on a solid MS medium containing 0.8% agar, 3% sucrose and 0.05mg/l of IAA, BAP and kinetin. Shoot regeneration has been achieved in liquid MS medium containing 0.5mg/l each of IAA, BAP and kinetin. Multiple shoots were obtained on liquid MS medium containing 0.01mg/l IAA, 0.5mg/l each of 6- benzyl aminopurine (BAP), kinetin and rooting occurred in 1/2 strength liquid MS medium with 5.0 mg/l NAA and 0.01 mg/l each of BAP and kinetin. To detect the genetic purity of in vitro raised plantlets, expression of iso-peroxidases in donor plants andin vitro raised plantlets was compared through native PAGE. Different genotypes showed marked variation regarding number, position and intensity of bands. Micropropagated plantlets showed identical pattern of peroxidases to their parental clones. The genetic stability of micro propagated plantlets was also tested by RAPD analysis. The banding pattern of PCR amplified products from micro propagated plantlets was monomorphic based on RAPD profile in all the varieties. RAPD analysis and peroxidase isozyme pattern confirmed the genetic purity of sugarcane plantlets derivedin vitro.