Genetic characterization and field evaluation to recover parental phenotype in transgenic sugarcane: a step towards commercial release

NOGUERA, A.; ENRIQUE, R; PERERA, M.F.; OSTENGO, S.; RACEDO, J.; COSTILLA, D.; ZOSSI, S.; CUENYA, M.I.; FILIPPONE, M.P.; WELIN, B. AND CASTAGNARO, A.P.

MOLECULAR BREEDING

SPRINGER

Lugar: Berlin; Año: 2015

1380-3743

Sugarcane commercial variety RA 87-3was transformed with a genetic construct harboringthe epsps gene from Agrobacterium strain CP4conferring tolerance to glyphosate and nptII gene forkanamycin selection. Transformed lines were multipliedin greenhouse, and herbicide tolerance wasevaluated using different concentrations (3, 4, 8 and16 l/ha) of glyphosate (Helm 48 %p/v). All herbicidetolerant(HT) lines were field tested to confirmglyphosate tolerance and perform preliminary evaluationsof phenotypic resemblance to parental cultivar.All transformed lines maintained herbicide tolerance,but many showed phenotypic changes and/or growthaberrations. Ten HT lines, showing close growthresemblance to RA 87-3, were analyzed using ninecompulsory morphologic markers proposed by theInternational Union for the Protection of New Varietiesof Plants (UPOV) and 339 molecular markers.Out of the ten HT lines tested, six showed minormorphologic and genetic variations and were selectedfor field testing over two vegetative crop cycles (plantcane and first ratoon) at two production areas inArgentina. The six field-tested HT lines were found tobe almost indistinguishable when comparing agronomicand industrial characteristics and chemicalcomposition. Stable heritance of the CP4 epsps geneand glyphosate tolerance throughout different clonalgenerations were confirmed by RT-qPCR and Southernblot. Taking into account all results, two out of thesix lines tested were selected for a possible commercialrelease. Our study confirms the utility of genetictransformation as a complementary tool to classicalbreeding procedures and highlights the usefulness ofUPOV traits together with molecular markers for earlyselections of transgenic events that closely resembletheir parental genotype.