As fungal disease hits sugar output in UP, new cane variety holds hope

Why in the News

Uttar Pradesh, India’s top cane growing State, saw its sugar output fall from 126.4 lakh tonnes in 2019-20 to 89.5 lakh tonnes in 2025-26, mainly because its dominant cane variety, Co-0238 (Karan 4), succumbed to red rot. A new variety, Co-20016 (Karan 20), bred by the Indian Council of Agricultural Research’s Sugarcane Breeding Institute (ICAR-SBI) at Coimbatore, has been picked as its replacement and now awaits formal release.

What is red rot, and why did it break Co-0238?

1. What red rot is: Red rot is a sugarcane disease caused by the fungus Colletotrichum falcatum. It rots the stalk from inside, so infected fields give far less cane.
2. Why Co-0238 spread: ICAR-SBI released Co-0238 in 2009. It resisted the strains of the fungus (pathotypes) then common and gave high yields, so farmers planted it widely.
3. What went wrong: Planting one variety everywhere, monoculture, is like a town using one lock: one key opens every door. The fungus evolved a new strain, the CF13 pathotype, and Co-0238 lost its resistance (varietal breakdown).
4. An ignored warning: Co-0238’s breeder had warned against over planting it in the central, eastern and Terai belts, whose waterlogged fields spread the fungus’s spores. Mills and farmers ignored him.
5. The takeaway: Genetic uniformity let one mutated fungus hit a whole State’s crop, so the variety behind UP’s rise caused its fall.

How did one variety shape UP’s sugar economy?

1. Rise to the top: For nearly a decade, Co-0238 made UP India’s top sugar producer, overtaking Maharashtra.
2. Cane crushed: UP’s mills crushed over a fifth less cane in the latest season than at their 2019-20 peak.
3. Recovery held up: Sugar recovery, the share of sugar extracted from cane, stayed near 10.8% in 2025-26, so the fall came from less cane, not poorer cane.
4. Electoral stake: UP votes for its Assembly in February-March 2027, so the shrinking crop falls in a politically sensitive year.

Why is Co-20016 seen as the replacement?

1. Industry trials: The Indian Sugar & Bio-energy Manufacturers Association (ISMA) began joint trials with ICAR-SBI in August 2023 across two zones:
   • subtropical: UP, Uttarakhand, Bihar, Haryana, Punjab;
   • tropical: Maharashtra, Karnataka, Tamil Nadu, Gujarat, Madhya Pradesh, Andhra Pradesh, Telangana.
2. Test design: Co-20016 and a second variety, Co-21012, were grown over two plant crops and one ratoon crop (cane regrown from stubble).
3. Higher yield and sucrose: Co-20016 averaged 144.6 tonnes per hectare against 116.4 for Co-0238. Its juice also carried more sucrose, the sugar that mills extract.
4. Red rot resistance: Most important, Co-20016 resists the CF13 pathotype that broke Co-0238.

What stands between Co-20016 and farmers’ fields?

1. Varietal identification: A Varietal Identification Committee of the All-India Coordinated Research Project (AICRP) on Sugarcane, ICAR’s multi location testing network, picked Co-20016 on 27 May.
2. Formal release: The Central Varietal Release Committee, which clears varieties for commercial cultivation, is expected to meet in October.
3. Planting windows: Once released, Co-20016 can be planted in spring (February-March), summer (April-May) or autumn (mid-September to mid-November).

Challenges

1. A new monoculture: Planting Co-20016 as widely as Co-0238 invites a fresh pathotype to break it too.
2. Slow seed multiplication: Cane is planted from stem cuttings (setts), so seed of a new variety takes seasons to build up.
3. Infected planting material: Setts from diseased fields carry the fungus into new plantings, whatever the variety.

Way Forward

1. Cap any one variety’s share: UP’s cane development department should limit each variety’s area share in a mill zone.
2. Disease free nurseries: ICAR-SBI and mills should raise tissue culture seed of Co-20016, grown from plant cells in a laboratory, ahead of release.
3. Pathotype surveillance: ICAR should track red rot strains each season to flag a breakdown early.

Conclusion

UP’s sugar decline shows a high yielding variety turning into a single point of failure once one strain of fungus learned to beat it. What to watch is the release committee’s decision this autumn, and whether mills plant the new variety alongside others rather than as the next monoculture.

Key numbers

1. UP cane crushed: about 769 lakh tonnes (2011-12), a peak of about 1,118 lakh tonnes (2019-20), about 878 lakh tonnes (2025-26).
2. Pathotypes Co-0238 resisted at release: CF07 and CF08.
3. ISMA and ICAR-SBI trial sites: 16 mills, 11 of them in UP.
4. Sucrose in juice at ten months (ISMA trials): 18.7% for Co-20016 against 18.3% for Co-0238.
5. UP sugar recovery (State cane department): 9.07% in 2011-12, above 10.5% from 2015-16.

Matching Previous Year Question

“[2026, GS3, 15 marks] How Indian agriculture has been transformed from food scarcity to food surplus level? Explain the various government policies implemented for diversification of Indian agriculture.”