In vitro Induction of Colchiploidy in an Intergeneric Hybrid of Sorghum×Saccharum

Abstract

A rare hybrid of Sorghum×Sugarcane was produced at Sugarcane Breeding Institute during 1996 which had a chromosome number 2n=66. This hybrid lacked vigor and was poor with respect to agronomic traits. Attempts were made to create genetic variation in this hybrid through tissue culture and colchicine treatment. Calli induction and their differentiation to plantlets were obtained on modified MS medium. Different concentrations of colchicine (25 mg/l, 50 mg/l, 75 mg/l and 100 mg/l) were added to the differentiation medium. There was no differentiation in the medium containing 75 mg/l and 100 mg/l colchicine, while calli treated with 25 mg/l and 50 mg/l colchicine produced 230 plants. The regenerated plants obtained were rooted, hardened and established in pots as well as in the field and cytomorphologically characterized. Though the somaclones were morphologically similar to the original hybrid in almost all the characters, the cytological analysis revealed the occurrence of polyploidy in these calli clones. Chimeric plants were also obtained during in vitro polyploidization. The results indicate that colchicine could be efficiently utilized for induction of polyploidy in Saccharum hybrids.