Progress in understanding fungal diseases affecting sugarcane: red rot

Abstract

There has been great success in developing many red rot resistant sugarcane varieties through conventional bi-parental crossing and varietal selection, although heritability of red rot resistance is complex Precise screening methods, testing sugarcane progenies under controlled conditions makes it possible to determine red rot resistance at an early stage in the breeding and selection programme. This has accelerated identification of the promising varieties. The identification of the molecular markers for red rot resistance in sugarcane also promises to have application in early progeny selection. Currently red rot resistant progenies possess resistance to one or few pathotypes of C. falcatum and further studies need to be done to broaden resistance from other sources such as Saccharum spontaneum and Erianthus spp with potential resistant genes. C. falcatum exhibits variation in cultural, morphological, pathogenic and molecular traits. Detailed analysis of the genome and transcriptome data of C. falcatum through comparative genomics has helped to identify pathogenicity or virulence genes, including unique genes in C. falcatum that are responsible for its particular effects on sugarcane. In future, candidate genes coding for e.g. wound-inducible proteins could be tested for expression in sugarcane to minimize damage caused by C. falcatum using transgenic techniques. Apart from varietal resistance, alternate strategies like induced systematic resistance (ISR) and systemic acquired resistance (SAR) show promise. Further going for nano formulations is also a promising approach to deliver inducers to manage the disease in a sustainable way. Improved fungicide delivery to setts has been shown to contain disease development in young crops. Once the young crop is protected, secondary spread of the pathogen is reduced significantly