Evaluation of Agronomic and Industrial Traits, Genetic Variation, and Transgene Stability in Glyphosate-Tolerant Sugarcane

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

San Diego

Conferencia; PLANT AND ANIMAL GEMONE XXII; 2014

PAG

Sugarcane (Saccharum hybrid) commercial variety RA87-3 was transformed by particle bombardment with a chimeric transgene constitutively expressing gene epsps from Agrobacterium strain C4 conferring tolerance to the broad spectrum herbicide glyphosate. Out of 43 PCR-positives transformed lines, 17 showed high glyphosate-tolerance when tested under greenhouse conditions. Interestingly, many of the transformed lines (11) showed phenotypic differences and/or aberrant growth as compared to the parental line when planted in a small?scale field trial. To corroborate these field test results, events with parental phenotype, together with four lines showing growth or phenotypic differences, were genotypically analyzed using 15 TRAP markers. The six lines phenotypically indistinguishable from RA87-3, showed over 99% marker similarity when compared to the parental variety whereas the four lines with phenotypic alterations had less than 95% similarity. The six parental-related lines were evaluated to ensure comparable agronomic and industrial characteristics to their parental elite variety at the two major sugarcane production areas in Argentina during two consecutive growth seasons. All lines showed comparable agronomical and industrial traits as compared to parental line RA87-3, but two lines were found to be almost identical as compared to their parental origin, and were subsequently selected for possible commercialization. Our results show that even though, only a relatively low number of genetically transformed lines are produced in a sugarcane variety it is possible to recuperate a closely related copy of the parental line demonstrating the usefulness of molecular breeding for this genetically complex crop species.