Evaluation of sugarcane genotypes against yellow leaf disorder under field conditions in subtropical India

Sugarcane yellow leaf (YL) caused by Sugarcane yellow leaf virus (ScYLV) and leaf yellows (LY) caused by Sugarcane leaf yellows phytoplasma (SCYP) is major constraint in sugarcane cultivation. In the present study, identification of resistance sources against YL or LY under field conditions were carried out on 142 sugarcane genotypes evaluated during 2016-2017 and 2017-2018 crop seasons. Field evaluation was carried out using 0-5 rating scale. Among the 142 sugarcane genotypes, 102 genotypes during 2016-2017 and 86 genotypes during 2017-2018 season showed resistant reaction against yellowing. While 22 and 13 genotypes during 2016-2017 and 2017-2018 crop seasons, respectively, showed moderately resistant reaction. Similarly, 13 genotypes showed moderately susceptible reaction against leaf yellowing during both the crop seasons. The presence of phytoplasma in 55 symptomatic sugarcane genotypes was detected by nested PCR assay. The 86 asymptomatic sugarcane genotypes were found as a source of resistance against LY from the present investigation.