Management of varietal degeneration in sugarcane through tissue culture combined with virus testing

Abstract

Tissue culture techniques are suggested to eliminate viruses from systemically infected plants in vegetatively propagated crops. Here also inadvertent virus presence in the seedlings would be catastrophic since this will spread the disease throughout the field. Hence virus diagnosis is always recommended for tissue culture raised plants to ensure their freedom from the viruses. Advancements made in molecular diagnosis were capitalized to standardize diagnostics for sugarcane viruses and phytoplasmas at the institute. The institute also received accreditation for virus indexing of tissue culture raised seedlings in sugarcane from Department of Biotechnology, New Delhi under National Certification System of Tissue Culture raised Plants (NCS-TCP). The virus indexing has been introduced as a service to sugar industry to produce disease-free seedlings. This venture has helped many sugar industries to revive degenerated varieties during the past five years. During the course we have indexed ~1200 batches of tissue culture samples (in vitro stock cultures) from different tissue culture production units spread over Tamil Nadu, Andhra Pradesh, Maharashtra and Gujarat for the viruses SCYLV, SCMV and SCSMV and grassy shoot phytoplasma by RT-PCR/PCR techniques. Close scrutiny of our test reports revealed that the tissue culture production units have improved their skills in producing disease-free planting materials. Under field conditions, disease-free nurseries of the popular variety Co 86032 were developed and varietal degeneration was averted in the regions where clean seed nursery programmes were followed. This approach will sustain sugarcane productivity in the country by exploiting the yield potential of many popular varieties without degeneration. However, considering the area under sugarcane cultivation, adoption of clean seed nursery programme is far less in the country. To increase overall production of the crop in the country, sugar industry should take up large-scale adoption of healthy seed nursery programmes.