Protocol Optimization for In Vitro Regeneration System in Frost SensitivePotato Genotypes: As a Basis for Genetic Transformation Studies inSolanum tuberosum L.

For genetic transformation, an efficient in vitro regeneration system in frost sensitive potato genotypes was established in this research study. Two frost sensitive genotypes of potato viz, Kuroda and FD-51-5 with good agronomic features but sensitive to frost were used. Six callus formation media were investigated for callus formation, in which three levels of 2, 4-D (3.5 mg/L, 4.5 mg/L and 5.5 mg/L) alone and in combination with one level of NAA (0.25 mg/L) were used. Of these, four callogenesis media viz, CM1, CM2, CM3 and CM4 were proved to be best for callus formation while genotype Kuroda gave best response. So these four CM and genotype kuroda was selected for in vitro regeneration study in which five regeneration media (RM) were investigated. In these media three levels of BAP (2.75 mg/L, 3.75 mg/L, and 4.75 mg/L) and one level of NAA and kinetin (0.25 mg/L) were used in different combinations. For in vitro regeneration, two age groups of calli viz, 28 days old and 35 days old were studies to check the effect of calli age in vitro regeneration. These calli of genotype kuroda were induced on selected CM and then were put on these RM. Thereby results showed that twenty eight days old calli of genotype Kuroda from CM2 when shifted on RM4 gave maximum number of shoots.