Evaluation of elite sugarcane clones/varieties against red rot disease (Colletotrichum falcatum) and their suitability in crop improvement programme

Abstract

Abstract. To manage red rot disease in sugarcane, several methods like use of bio-control agents, hot water and hot air treatment of setts, chemical fungicides, various cultural practices like use of disease free setts, rouging, crop rotation, irrigation management, avoiding rationing, etc. are practised. But none of the practices are able to control the disease. The most viable strategy is to manage through host plant resistance. Thus, a field experiment was conducted for two consecutive years during 2019 and 2020 at the Research Farm of Sugarcane Research Station, Bethuadahari (West Bengal), India to evaluate some elite sugarcane clones/varieties against red rot disease. The elite clones/varieties were laid out in Completely Randomized Block Design with a plot size of 2R x 6m x 0.90m with 2 replications and two red rot pathotypes Cf 07 and Cf 08 were used for artificial inoculation in plug and nodal method. The experiment revealed that the sugarcane clones CoP 16436, CoP 16437, CoP 16438, CoLk 16466, CoLk 16467, CoLk 16468, CoSe 16451, CoP 16439, CoP 16440, BO 156, CoLk 16469, CoLk 16470, CoLk 16471, CoSe 16452, CoSe 16453, CoSe 16454, CoP 17436, CoP 17437, CoP 17438, CoP 17440, CoP 17441, CoSe 17451, CoSe 16455, CoSe 16456, CoP 17444, CoP 17446 and CoSe 17452 were found as moderately resistant (MR) in plug method and resistant (R) in nodal method to both pathotypes and can be used for further evaluation in subsequent varietal developmental as well as breeding programme. The popular sugarcane varieties, namely CoLk 94184, CoSe 01421, BO 91, CoP 9301 and CoP 06436 were found as moderately resistant (MR) in plug method and resistant (R) in nodal method and can be continued for commercial cultivation as well as red rot breeding programme. As the existing popular variety CoSe 95422 was found moderately susceptible (MS) in plug method and susceptible (S) in nodal method to Cf 07 and Cf 08 red rot pathotypes, thus the variety must be discarded from commercial cultivation with immediate effect.