TWA Balsalobre1, GK Oliveira2, LY Campana2, FZ Barreto2, RG Chapola1,2, HP Hoffmann1,2 and MS Carneiro1,2
1Sugarcane Breeding Program of RIDESA/UFSCar, Araras, SP, Brazil; monalisa@ufscar.br
2Federal University of São Carlos, Araras, SP, Brazil
Molecular markers associated with resistance genes, such as Bru1 (brown rust) and G1 (orange rust), hold significant potential for predicting resistant genotypes during the selection phases of breeding programs. We aimed to correlate the phenotypic response with the genotypic profiles of Bru1 and G1 markers in a panel of 300 sugarcane accessions, which constitute the Brazilian Panel of Sugarcane Genotypes (BPSG). Among the evaluated accessions, 60.3% (181) exhibited field resistance to brown rust, of which 70.7% (128) carried the Bru1 gene. The presence of Bru1 was confirmed through the simultaneous amplification of two molecular markers, R12H16 and 9O20-F4-RsaI. For field-resistant accessions lacking these two markers, further investigation is underway using additional molecular markers to rule out false negatives. Preliminary results revealed that among 11 field-resistant genotypes previously identified as lacking the resistance gene, seven (63.6%) successfully amplified alternative molecular markers associated with Bru1. Regarding orange rust, 96.3% (288) of the accessions showed field resistance, with 52.7% (152) carrying the G1 marker. These findings highlight the critical role of Bru1 molecular markers in the early selection of brown rust-resistant genotypes within sugarcane breeding programs.