Behavior of sugarcane germplasm of the Sugarcane Breeding Program (EEAOC) against Puccinia kuehnii, the causal agent of orange rust, in Misiones, Argentina

CLAUDIA FUNES; SOLANA CHAVES; MATIAS AYBAR GUCHEA; MARÍA INÉS CUENYA; DIEGO DANIEL HENRIQUEZ; ROMINA PRISCILA BERTANI; HERNAN GUTIERREZ; DIEGO DANIEL COSTILLA; CONSTANZA MARÍA JOYA; VICTORIA GONZALEZ

Congreso; XXX ISSCT Congress; 2019

In April 2015 orange rust was detected for the first time in a commercial sugarcane field in a province of northeast of Argentina (Misiones) 1200 km from the main sugarcane area of this country. The objective of this study was to evaluate the behavior of sugarcane germplasm of the Sugarcane Breeding Program (SCBP) of the Estación Experimental Agroindustrial Obispo Colombres (EEAOC) against Puccinia kuehnii under field conditions. In September 2015, 192 sugarcane clones were planted in a field trial in Fachinal, Misiones. This material included the parents, among which are the commercial varieties grown in Tucumán, and other clones of the germplasm collection of the SCBP. An unknown variety at Misiones, affected with orange rust, was planted around the trial. Orange rust severity was evaluated between 2016 and 2018. Sugarcane leaf samples with rust symptoms were collected and examined in the EEAOC laboratory, and the identity of the causal agent was verified by PCR using specific primers. When microscopic observations were done, uredinia and urediniospores previously described for P. kuehnii were detected in 23 (11.98%) and 15 (7.81%) genotypes in 2016 and 2017, respectively. P. kuehnii was not detected in 2018. Furthermore, a high percentage of P. kuehnii and P. melanocephala co-infection was observed during 2016 and 2017, resulting in 78.26% and 93.33% of the total positive samples for P. kuehnii, respectively. Results revealed the existence of potential resistant sources against orange rust in the germplasm collection of the SCBP (EEAOC) since 88% of the genotypes were disease-free during the three-year evaluation.