02036naa a2200241 a 450000100080000000500110000800800410001902200140006002400270007410000190010124501620012026000090028252012880029165000160157965000140159565000210160965000240163070000270165470000280168170000170170970000230172677300450174920959882018-09-18       2018    bl uuuu     u00u1 u    #d  a1365-30597 a10.1111/ppa.128892DOI1 aMOREIRA, A. S.  aDistinguishing sporulating and nonsporulating lesions as a method for evaluating the resistance of sugarcane genotypes to orange rust.h[electronic resource]  c2018  aSugarcane breeding programmes rank the resistance of genotypes to Puccinia kuehnii, causal agent of orange rust, according to levels of disease severity. However, during the screening stages, this method of assessment can lead to precipitous elimination of genotypes with promising agronomic traits but showing mild symptoms of rust such as flecks or lesions that do not produce spores. This study aimed to propose a new method to classify the resistance of sugarcane genotypes to orange rust by counting sporulating lesions. Five sugarcane varieties with different levels of resistance to P. kuehnii were inoculated with two pathogen populations under controlled conditions. The disease severity (SEV), total number of lesions (TNL), and total number of sporulating lesions (TNSL) were evaluated in a 20 cm leaf fragment from the most diseased leaf. The TNL and TNSL evaluations were performed at 11, 16 and 21 days after inoculation (DAI) and SEV at 21 DAI. The thresholds of 80% and 8% of sporulating lesions (SL) separated susceptible from the intermediate varieties and intermediate from the resistant ones, respectively. It is proposed that the method of counting sporulating lesions be used in screening genotypes for resistance to P. kuehnii in sugarcane breeding programmes.  aOrange rust  aSugarcane  aCana de Açúcar  aFerrugem Alaranjada1 aNOGUEIRA-JUNIOR, A. F.1 aGONÇALVES, C. R. N. B.1 aSOUZA, N. A.1 aBERGAMIN FILHO, A.  tPlant Pathologygv. 67, 1680-1686, 2018.