COMPLEX GENETICS OF SUGARCANE LIMITS BUT DO NOT PRECLUDE IDENTIFICATION OF TRANSFORMED LINES WITH PARENTAL PHENOTYPE

ALDO NOGUERA, RAMÓN ENRIQUE, SANTIAGO OSTENGO, FRANCISCA PERERA, JOSEFINA RACEDO, DIEGO COSTILLA, MARÍA INÉS CUENYA, BJÖRN WELIN AND ATILIO CASTAGNARO

Mar del Plata

Encuentro; VIII Encuentro Latinoamericano y del Caribe de Biotecnología; 2013

Sugarcane (Saccharum hybrid) commercial variety RA87-3 was transformed through particle bombardment with a chimeric transgene constitutively expressing the gene epsps from Agrobacterium strain C4 conferring tolerance to glyphosate. Out of thirty six PCR-positive transformed lines, seventeen showed high glyphosate-tolerance when tested in the greenhouse and were selected for further field studies. In a small?scale field trial glyphosate tolerance was verified and phenotypic resemblance to parental line RA87-3 evaluated. Most transgenic events showed clear growth difference, leaving only six lines with close physical appearance and growth resemblance to the parental variety. All six lines showing a parental phenotype were genetically indistinguishable from the parental line as seen by analyzing 339 polymorphic molecular markers. The six lines were selected for field testing at two independent sugarcane production areas in Argentina and evaluated for agronomic traits and biochemical parameters. In accordance with the phenotypical and genetic evaluation, all 6 lines were found to be almost identical to RA87-3 when analyzed for agronomical traits and chemical composition. Our results demonstrate the usefulness of molecular breeding for this genetically complex plant species and the possibility to recover transformed lines indistinguishable of a parental elite variety, which is of great importance for commercial liberation.