Kosi
CSIR-CIMAP menthol mint released in 1999 (about 80% menthol), a half-sib selection from HY-77 (Kalka); early-maturing, suited to later planting, and among the varieties with the most stable oil yield across years and sites.
Quick facts
- Type
- Sucker (improved variety)
- Season
- Zaid / summer
- Maturity period
- About 90–100 days to the first cut
- Seed rate
- About 400–450 kg of fresh suckers per hectare (roughly 160–180 kg per acre)
- Expected yield
- About 100–150 kg oil/ha in a typical season; 188.7 kg/ha in the breeder's 1996 trial
- Suitable soil
- Well-drained, organic-matter-rich loam or sandy loam
- Release
- Released 1999 · CSIR-CIMAP, Lucknow (US plant patent filed June 1998, published February 2002)
About this variety
Kosi is a CSIR-CIMAP menthol mint (Mentha arvensis) released in 1999. It was bred by half-sib selection from open-pollinated seed of the variety HY-77 (Kalka) at CIMAP's Pantnagar field station; the US plant patent was filed in June 1998. It carries about 80% menthol in the oil (CIMAP lists 75–80%, the patent 81–83%) and oil content of about 0.75% of fresh herb. It matures early — first harvest at about 90–100 days against about 110 for standard varieties — and has a rounded, evenly branched canopy that lets sunlight reach the lower leaves. In the breeder's 1996 trial it gave about 189 kg of oil per hectare, and the patent describes it as tolerant of leaf spot, rust and powdery mildew. In multi-year, multi-location comparisons, Kosi (with Kushal and CIMAP-Saryu) showed the most stable oil yield.
Key characteristics
Sowing & cultivation
- Sowing timeSuits later planting (late February to March) because it matures early
- Seed rateAbout 400–450 kg of fresh suckers per hectare (roughly 160–180 kg per acre)
- SpacingRows 45–60 cm apart, suckers laid end to end (about 10 cm apart) in furrows 5–6 cm deep
- Sowing methodLay fresh, healthy suckers in moist furrows, cover lightly with soil and irrigate at once
- IrrigationA light irrigation at planting and a week later, then about every 10–12 days through the summer (roughly ten irrigations); stop about a week before each cut
- FertilizerAbout 120 kg N, 60 kg P₂O₅ and 40 kg K₂O per hectare with about 20 t FYM, the nitrogen split over three to four doses including one right after the first cut (NHB mint package)
- HarvestingFirst harvest at about 90–100 days (against about 110 for standard varieties in the breeder's trials); distil promptly and give nitrogen and water for the second cut
Soil & climate
Soil
- Suitable soil
- Well-drained loam or sandy loam rich in organic matter, pH about 6–8.2
- Irrigation
- Good drainage is essential — water must never stand around the suckers and stolons
Climate
- Maturity
- About 20–40°C through the growing period
- Irrigation
- Light rain at planting and dry, sunny weather at harvest; largely an irrigated crop in the plains
Yield & maturity
Maturity period
About 90–100 days to the first cut
Expected yield
About 100–150 kg oil/ha in a typical season; 188.7 kg/ha in the breeder's 1996 trial
Actual yield depends on sowing time, soil, irrigation, weather, seed quality and crop management.
Pest & disease considerations
Management notes
- Plant fresh, healthy suckers dipped in a recommended fungicide, and renew planting stock every couple of years.
- Keep the crop weed-free from about 4 to 14 weeks after planting — nutsedge is the worst weed.
- Cut on a bright, sunny day and distil the same or next day; give nitrogen and water straight after the first cut.
Advantages & considerations
Why farmers may choose it
- Early-maturing — first cut at about 90–100 days
- Reported tolerant of leaf spot, rust and powdery mildew (breeder's patent)
- Among the most stable oil yielders across years and sites
Things to consider
- Stable rather than the highest-yielding type — newer varieties such as CIM-Unnati report higher potential
- Tolerance is a breeder's claim, not immunity — still watch for mildew and rust in humid spells
- Check genuine planting material with CIMAP or a KVK before buying
Suitable regions
States this variety is recommended for — check locally, since a state can have more than one recommended zone.
- Uttar Pradesh
- Bihar
- Punjab
- Haryana
Frequently asked questions
Is Kosi good for late planting?
Yes. Kosi is an early-maturing variety — first harvest at about 90–100 days against about 110 for standard varieties — so it suits a field that is only free after another crop. For the very latest, April, planting, CIMAP's Kushal was specifically developed and out-performed Kosi in its trials.
How much menthol does Kosi oil carry?
About 80%. CIMAP's variety record lists 75–80% menthol, and the breeder's patent reports 81–83%, alongside menthone, methyl acetate and isomenthol.
Sourced from: CSIR-CIMAP, Lucknow, CSIR Aroma Mission, National Horticulture Board — Mint. editorial policy.