Seed Treatment for Direct-Seeded Rice: What the Shift Away from Transplanting Actually Demands of the Seed

Executive Summary

Direct-seeded rice asks the seed to do work a nursery used to do for it. Under puddled transplanting a rice seed germinates in a saturated, hand-tended bed and reaches the field as a three-week-old plant with roots already made. In dry direct-seeded rice (DSR) the same seed is drilled into dry or barely moist soil and must emerge, root and compete on its own. Indian field research shows that the gap between those two situations is, to a usable extent, a seed-treatment problem.

The strongest Indian evidence is for seed priming: at Punjab Agricultural University, Ludhiana, halopriming with 2.0% potassium nitrate and hormopriming with 50 ppm gibberellic acid each raised DSR grain yield by 7–11% over non-primed dry seed in both kharif 2018 and 2019. A Haryana bakanae survey produced the most interesting result of all: dry sowing by itself carried less disease than sprouted seed in puddled beds. Against that, a Telangana trial of imidacloprid 48% FS controlled thrips for a month and then delivered no yield difference — a reminder of how narrow a seed dresser's window is.

What Direct Seeding Takes Away From the Rice Seed

Jagmohan Kaur and Avtar Singh of the Department of Agronomy at PAU Ludhiana, reviewing the system in Current Agriculture Research Journal in 2017, list DSR's advantages as saved labour, less water, less drudgery, earlier maturity, lower production cost, better soil physical condition for the following crop and lower methane emission. Shekhawat, Rathore and Chauhan, writing in Agronomy in 2020 from ICAR-IARI and the University of Queensland, put roughly 22% of Asia's rice area under some form of direct seeding.

The PAU review is equally plain about the constraints: heavy weed infestation, weedy rice, more soil-borne pathogens including nematodes, nutrient disorders, poor crop establishment, lodging, and higher incidence of blast and brown leaf spot. That list maps closely onto what direct seeding removes — the nursery, the puddle and the standing water. Each was doing quiet protective work, and the seed now has to replace some of it.

Priming for Crop Establishment: The Strongest Indian Evidence

Buta Singh Dhillon and co-workers at PAU Ludhiana, with Virender Kumar of the International Rice Research Institute, ran the study that most directly answers the question. Reported in Agronomy in 2021, it tested dry non-primed seed against hydropriming, halopriming with 2.0% potassium nitrate, hormopriming with 50 ppm gibberellic acid (GA3) and osmopriming with polyethylene glycol at −0.6 MPa, each for 12 and 24 hours, in the laboratory and in DSR field plots over kharif 2018 and 2019.

Halopriming and hormopriming at Ludhiana

In both years, 2.0% KNO3 and 50 ppm GA3 produced a 7–11% grain yield increase over the non-primed control, which the authors attribute to faster germination and emergence, better root growth and the improved yield attributes that followed. Osmopriming with PEG gave 4% in 2018 and nothing in 2019 — an inconsistency worth stating, because it is the kind of result that disappears from promotional summaries. In 2019 the trial also ran under both conventional DSR and soil-mulch or vattar DSR, where seed goes into moist soil after a pre-sowing irrigation. The two methods did not differ in grain yield, and the benefit of priming did not differ between them or between 12 and 24 hours of soaking. The shorter soak is enough, and the sowing method does not change the seed-treatment decision.

A wider panel of priming agents

A two-season study conducted in 2022 and 2023 in the north-western Indo-Gangetic Plains, published in the Indian Journal of Plant Genetic Resources, widened the panel across two cultivars: hydropriming, nanopriming with 25 ppm zinc oxide nanoparticles, hormonal priming with 50 ppm GA3, halopriming with 1% KNO3 and ascorbic acid at 100 ppm. Every agent significantly improved germination, seedling length and vigour in the laboratory and crop stand in the field. Hormonal priming was significantly superior in the laboratory, but in the field all agents were equally effective — and the yield gain came through the same route each time: more plants per m², therefore more panicles per m².

Seed-Applied Interventions Tested in Indian DSR Systems

Two cautions: the nematode row reports per-plot applications, not a seed dressing, and the imidacloprid row comes from a nursery-and-transplant trial, so its bearing on DSR is an inference about duration of protection.

Seed-Borne Disease in a Dry Seedbed

The 2025 paper by Dhillon and colleagues in the Journal of Phytopathology states the problem in its opening line: inadequate establishment and a higher incidence of diseases such as brown spot and neck blast are among the main reasons DSR has not scaled. That is a disease argument for seed treatment, not merely a vigour argument. In that study, 25 ppm GA3 or 2% KNO3 priming followed by a mancozeb 50% + carbendazim 25% WP dressing gave low severity across all six diseases assessed — bacterial blight, brown spot, foot rot, neck blast, bunt and grain discolouration — and the highest plant population, panicle number, filled grains and yield. The published abstract does not quantify the yield difference, so neither do we.

Brown spot: a stress disease in a stress-prone system

Brown spot (Bipolaris oryzae, also reported as Drechslera oryzae) responded to the seed dressing in that PAU study, which is the practical reason it belongs in a seed-treatment discussion. In a multi-institution review led by Manoj Kumar Barnwal in the European Journal of Plant Pathology in 2013, it is described as conventionally regarded less as a true infectious disease than as the signature of a rice crop under physiological stress, drought and poor soil fertility in particular. That review reports yield losses from 4% to 52% while noting explicitly that accurate, systematic estimates are lacking. Both halves matter: a loss range that wide is not a number to build a claim on, but a disease tracking drought stress is exactly what a non-flooded rice system should expect more of.

Bakanae: the result that favours dry sowing

Shyam Sunder, Ram Singh and D. S. Dodan of CCS Haryana Agricultural University surveyed bakanae across Haryana's paddy belt and reported in the Indian Journal of Agricultural Sciences in 2014 that incidence had risen considerably since the disease was first recorded in the state in kharif 1988, becoming a major problem particularly in scented varieties. The pathogen is Fusarium fujikuroi, reported there under its earlier name Fusarium moniliforme.

Their establishment-method comparison is the finding a DSR grower should know. Incidence was significantly lower where seed was sown under dry conditions — and this held for treated and untreated seed alike — than under the conventional practice of sowing sprouted seed into puddled beds. Separately, both dry dressing and seed soaking with carbendazim at 1 and 2 g per kg of seed suppressed the disease considerably. Direct seeding, then, is not uniformly worse for seed-borne disease. For bakanae in basmati the shift away from the puddled nursery appears to work in the grower's favour, with seed treatment adding to that advantage rather than rescuing a loss.

Root-Knot Nematode: The Pest Direct Seeding Stops Drowning

Of everything on the DSR constraint list, the rice root-knot nematode Meloidogyne graminicola has the clearest mechanistic link to the loss of standing water. A 2017 review by H. Ravindra and colleagues at ICAR's National Research Centre for Integrated Pest Management and the University of Agricultural and Horticultural Sciences, Shivamogga, puts reported losses in a wide band of 16–80% and lists field flooding among the established eco-friendly controls, alongside removal of host weeds, summer ploughing, organic amendments, biocontrol agents and resistant cultivars. An aerobic DSR field removes the flooding option by design.

The pressure is already there. Mujeebur Rahman Khan and Faheem Ahamad of Aligarh Muslim University, surveying more than 800 paddy fields across 18 major rice districts of Uttar Pradesh from 2013 to 2015, reported in Plant Disease in 2019 that the frequency of root-knot disease reached 44.6% in Aligarh, followed by Muzaffarnagar at 29.3%, with average soil populations running from 3,851 ± 297 second-stage juveniles per kg of soil in Aligarh down to 695 ± 400 in Barabanki.

The one Indian field experiment run specifically under direct seeding was reported by Pooja R. M., H. Ravindra, M. Sehgal and co-workers in Plant Archives in 2021, from kharif 2019–20 at UAHS Shivamogga. Fluensulfone at 3 g per plot was best, recording a root-knot index of 2.0, grain yield of 36.87 q/ha and the lowest nematode population at 199 per 200 g of soil; the consortium of Pseudomonas fluorescens, Trichoderma harzianum and Bacillus megaterium at 20 g/m² ranked next, ahead of carbofuran, carbosulfan, neem cake and poultry manure. These were not seed treatments, and the honest conclusion is that a seed-delivered answer to M. graminicola in Indian DSR has not yet been demonstrated in published field work. It is the clearest open question in this area.

Insects: What a Seed Dresser Can and Cannot Buy

Direct seeding changes the pest complex rather than simply worsening it. A comparative study by K. N. Ashrith, published in Mapana Journal of Sciences in 2017 and covering rabi and kharif of 2013–14, recorded maximum leaf folder (Cnaphalocrocis medinalis) damage of 13.03% and yellow stem borer white-ear damage of 13.49% in DSR under unprotected conditions, in the last week of October and the second week of November respectively. Sucking pests went the other way, with green leafhopper incidence comparatively higher in puddled transplanted rice at 3.29 and 4.92 per hill across the two seasons, as were the planthoppers.

Note the dates: peak defoliator and borer damage in DSR arrived in late October and November, and no seed-applied insecticide reaches that far. The clearest Indian demonstration of that limit comes from S. Malathi, R. Shravan Kumar and P. J. M. Rao at the PJTSAU Regional Agricultural Research Station, Warangal, Telangana, reporting in Biological Forum in 2026 on a wet-season 2018 trial in the variety BPT-5204. Imidacloprid 48% w/w FS at 150 g a.i. per 100 kg of seed improved germination, was effective against thrips throughout the nursery stage and up to 30 days after transplanting, and caused no phytotoxicity. It also gave only marginal, statistically insignificant gains in shoot and root length at 35 days, and although treated plots carried more tillers, there was no difference in final panicle-bearing tillers and none in yield. That is a well-designed negative result: a seed-applied insecticide in rice is an establishment-window tool, buying a clean stand for about a month, and if the economic damage arrives at panicle initiation it is not the instrument that will address it.

Iron: A Nutritional Job the Seed Can Carry

Aerobic soil chemistry creates a problem flooded rice does not have. In a submerged field iron is reduced and freely available; in an aerobic DSR field on a coarse-textured soil it is not, and iron deficiency chlorosis is a recognised DSR disorder.

Vivek Sharma and colleagues in the Department of Soil Science at PAU Ludhiana tested whether the seed could carry the correction, reporting in Communications in Soil Science and Plant Analysis in 2024. Field experiments on sandy loam and sandy clay loam compared a control, a 1.0% ferrous sulphate foliar spray, seed priming with FeSO4·7H2O at 0.5% and 1.0% Fe, EDTA-chelated iron at 0.25% and 0.5% Fe, and iron oxide nanoparticles at 0.025% and 0.05% Fe. Priming with FeSO4·7H2O at 1.0% Fe gave the maximum grain and straw yields of the eight treatments, 6.23 and 11.9 t/ha — 62.3 and 119 q/ha — while EDTA-chelated iron at 0.5% Fe was the treatment that significantly raised iron concentration in grain and straw over the control. Texture mattered in both directions: the percentage yield increase was larger on the lighter sandy loam, while iron contents in grain, straw and foliage were higher on sandy clay loam. An iron priming recommendation for DSR is therefore soil-specific, and the foliar spray here is the comparison arm, not the preferred route.

Weeds, Economics and the Indian Seed Company

Weeds remain the headline constraint: Shekhawat, Rathore and Chauhan put potential yield loss from weeds in dry DSR at up to 50%, and weedy rice appears on the PAU constraint list as a distinct emerging problem of its own. Seed treatment has no herbicidal action whatever, and nothing here should suggest otherwise. What it does is alter the race: both PAU priming studies traced their benefit to faster, more uniform emergence and a higher plant population per m², and a crop that emerges two or three days earlier and stands evenly closes canopy sooner, giving Echinochloa and the other kharif grasses less room. That is a real contribution and a modest one, sitting underneath a herbicide programme rather than in place of it.

On cost, the most complete Indian dataset comes from the east. Periyasamy Panneerselvam, Virender Kumar, Narayan Chandra Banik and co-workers from ICAR's rice research institute at Cuttack, with IRRI, CIMMYT and Odisha University of Agriculture and Technology, ran on-farm trials from 2016 to 2018 across Mayurbhanj, Cuttack, Bhadrak and Puri, publishing in Field Crops Research in 2020. Their comparison was beushening, the prevailing practice of broadcasting ungerminated seed at more than 100 kg/ha and then ploughing the emerged crop at four to six weeks for weed control, with manual gap filling afterwards. Drill-DSR with integrated weed management raised grain yield by 1.7 t/ha in Mayurbhanj and 1.3 t/ha in Cuttack, though not in Bhadrak; combined with lower variable cost, net benefit rose by US$550, US$395 and US$166 per hectare in those three districts, in the units the authors report.

The seed-industry implication follows from the seed rate. A system broadcasting over 100 kg/ha and relying on ploughing and manual gap filling cannot justify much per-kilogram seed enhancement; a drill placing a metered rate into a prepared bed can, because every seed matters and the establishment cost per seed has already fallen. That is the commercial threshold at which treated, primed or coated DSR seed begins to make sense, and it is defined by the drill rather than by the treatment.

Application Guidance Grounded in the Cited Work

• Test the lot before choosing the dressing. Rice blast (Magnaporthe oryzae) and sheath rot (Sarocladium oryzae) are among the most prevalent seed-borne pathogens of rice, and work led by M. K. Prasannakumar in Scientific Reports in 2021 demonstrated a portable device detecting both in rice seed within 20 to 30 minutes.
• Prime with what worked in both years — in the PAU trials, 2.0% KNO3 or 50 ppm GA3. Twelve hours performed as well as 24, and the benefit held under both conventional and vattar DSR. PEG osmopriming was inconsistent across seasons.
• Prime, then dress. The 2025 PAU basmati work applied the fungicide after priming, and that is the sequence its disease-severity results belong to. Priming is a wet operation performed close to sowing: the published protocols soak and then sow.
• Match the dressing to the recorded disease. Carbendazim at 1–2 g/kg seed, dry or as a soak, is the Haryana evidence for bakanae in scented rice; mancozeb 50% + carbendazim 25% WP is what the PAU study used against its six-disease panel.
• Size the insecticide decision to a one-month window. For early thrips or a thin stand, a seed-applied insecticide is the right tool; for leaf folder or stem borer in late October it is not.
• Treat iron priming as soil-specific, and expect no weed control from any of this beyond earlier canopy closure through a better stand.

Where Yaduka Agrotech's Registrations Fit, and Where They Do Not

Yaduka Agrotech Limited holds nine registrations granted under Section 9(4) of the Insecticides Act, 1968. Because this post concerns rice, most are not relevant.

Imidacloprid 48% FS (CIR-367397/2026-Imidacloprid (FS) (472)-639) carries rice among its label crops, alongside cotton, okra, sunflower, bajra, chilli, groundnut, jowar, maize, potato, soybean and wheat, for sucking pests. The dose in our own leaflet is expressed per hectare rather than per kilogram of seed, so no seed-rate figure for it is published here; the 150 g a.i./100 kg seed in the Warangal trial is that experiment's rate for another company's formulation of the same class, reported above as a research finding and not as a recommendation of ours.

Thiamethoxam 30% FS (CIR-367399/2026-Thiamethoxam (FS) (472)-1683) is registered to us as a seed dresser, but the specific condition on the certificate names cotton. Thiram 40% FS is certificated for seedling blight of maize, Carboxin 17.5% + Thiram 17.5% FF for loose smut of wheat, Tebuconazole 5.4% w/w FS for wheat, and the two metalaxyl products for downy mildews of maize, pearl millet, sorghum and sunflower and white rust of rapeseed-mustard. None of those certificates covers rice and we do not extend them to it.

Seed Primer, our multilayer biopolymer coating carrying Trichoderma harzianum Th4d, has been validated through ICAR-IIOR work in oilseeds, which earlier posts on this site cover in detail. There is no published DSR rice dataset for it and we make no rice claim. What the wider literature supports is the delivery principle, not a rice result: a 2019 review in Frontiers in Plant Science led by Inês Rocha describes seed dressing, film coating and pelleting as the established routes for applying beneficial microbes to seed, and notes that binders and fillers can extend microbial survival. Indian interest in the biological route for rice is real — Prashant Singh, Ramji Singh and co-workers reported on seed biopriming with Trichoderma harzianum for growth promotion and drought tolerance in rice in Agricultural Research in 2022 — but that is their result, not ours.

A CIB&RC registration states what a company may sell and for which crop. It is never evidence that a product performs, and the two should not be presented together as though they were one claim.

Conclusion

Direct seeding transfers responsibility to the seed, and the Indian evidence on whether seed treatment can carry it is now specific enough to act on. Priming is the best-supported intervention: 7–11% yield gains from 2.0% potassium nitrate or 50 ppm gibberellic acid at Ludhiana, reproduced across two seasons and two DSR establishment methods, corroborated by a wider panel of agents in the north-western Indo-Gangetic Plains, and always through the same mechanism of a better stand. A fungicide dressing layered on priming lowered the severity of six diseases in basmati, and iron priming addresses an aerobic-soil disorder flooded rice never had.

Three limits are documented rather than suspected. A seed-applied insecticide protects for roughly a month and then stops, with no yield effect when damage comes later. Seed treatment does nothing about weeds except help the crop close canopy sooner. And no published Indian field study has yet shown a seed-delivered answer to Meloidogyne graminicola under direct seeding, in a system that has given up flooding as a control.

The counter-intuitive finding deserves the last word: Haryana's bakanae survey found dry sowing carried less disease than sprouted seed in puddled beds, treated or not. Direct seeding is not a uniformly harsher environment for the rice seed — it is a different one, and the seed treatment that suits it has to be chosen from evidence rather than carried over from the nursery.

References and Sources

• Dhillon, B. S., Kumar, V. et al. (2021). Seed Priming with Potassium Nitrate and Gibberellic Acid Enhances the Performance of Dry Direct Seeded Rice (Oryza sativa L.) in North-Western India. Agronomy, 11(5), 849. doi:10.3390/agronomy11050849
• Dhillon, B. S., Kumar, V., Kaur, N. et al. (2025). Impact of Seed Priming and Fungicide Seed Treatments on Disease Development, Crop Growth and Yield of Dry Direct-Seeded Basmati Rice in North-Western India. Journal of Phytopathology, 173(4). doi:10.1111/jph.70134
• Madaan, S., Ram, M. et al. (2026). Effect of Various Seed Priming Agents on Germination, Seedling Vigour and Grain Yield of Dry Direct-Seeded Rice in the Northwestern Indo Gangetic Plains of India. Indian Journal of Plant Genetic Resources, 39(2). doi:10.56093/ijpgr.v39i2.174774
• Sharma, V., Kharb, V., Dhaliwal, S. S. et al. (2024). Amelioration of Iron Deficiency in Direct Seeded Aerobic Rice with Iron Seed Priming. Communications in Soil Science and Plant Analysis. doi:10.1080/00103624.2024.2430345
• Sunder, S., Singh, R. & Dodan, D. S. (2014). Management of bakanae disease of rice caused by Fusarium moniliforme. The Indian Journal of Agricultural Sciences, 84(2). doi:10.56093/ijas.v84i2.38038
• Kaur, J. & Singh, A. (2017). Direct Seeded Rice: Prospects, Problems/Constraints and Researchable Issues in India. Current Agriculture Research Journal, 5(1), 13–32. doi:10.12944/carj.5.1.03
• Shekhawat, K., Rathore, S. S. & Chauhan, B. S. (2020). Weed Management in Dry Direct-Seeded Rice. Agronomy, 10(9), 1264. doi:10.3390/agronomy10091264
• Barnwal, M. K., Kotasthane, A. S., Savary, S. et al. (2013). A review on crop losses, epidemiology and disease management of rice brown spot. European Journal of Plant Pathology. doi:10.1007/s10658-013-0195-6
• Khan, M. R. & Ahamad, F. (2019). Incidence of Root-Knot Nematode (Meloidogyne graminicola) and Resulting Crop Losses in Paddy Rice in Northern India. Plant Disease. doi:10.1094/PDIS-12-18-2154-RE
• Ravindra, H., Sehgal, M., Narasimhamurthy, H. B. et al. (2017). Rice Root-Knot Nematode (Meloidogyne graminicola) an Emerging Problem. International Journal of Current Microbiology and Applied Sciences, 6(8). doi:10.20546/ijcmas.2017.608.376
• Pooja, R. M., Ravindra, H., Sehgal, M. et al. (2021). Integrated management of rice root-knot nematode, Meloidogyne graminicola under the direct-seeded condition. Plant Archives, 21(1). doi:10.51470/plantarchives.2021.v21.no1.039
• Malathi, S., Shravan Kumar, R. & Rao, P. J. M. (2026). Effect of Gaucho 600 FS (imidacloprid 48% w/w FS) Seed Treatment against Thrips in Rice. Biological Forum, 18(4), 36–40. doi:10.65041/biologicalforum.2026.18.4.6
• Ashrith, K. N. (2017). Status of Insect Pests and Natural Enemies of Direct Seeded and Transplanted Rice. Mapana Journal of Sciences, 14(4), 11–29. doi:10.12723/mjs.35.2
• Panneerselvam, P., Kumar, V., Banik, N. C. et al. (2020). Transforming labor requirement, crop yield, and profitability with precision dry-direct seeding of rice and integrated weed management in Eastern India. Field Crops Research. doi:10.1016/j.fcr.2020.107961
• Rocha, I., Ma, Y., Souza-Alonso, P. et al. (2019). Seed Coating: A Tool for Delivering Beneficial Microbes to Agricultural Crops. Frontiers in Plant Science, 10, 1357. doi:10.3389/fpls.2019.01357
• Singh, P., Singh, R., Madhu, G. S. & Singh, V. P. (2022). Seed Biopriming with Trichoderma harzianum for Growth Promotion and Drought Tolerance in Rice. Agricultural Research, 12(2), 154–162. doi:10.1007/s40003-022-00641-8
• Prasannakumar, M. K., Parivallal, P. B., Pramesh, D. et al. (2021). LAMP-based foldable microdevice platform for the rapid detection of Magnaporthe oryzae and Sarocladium oryzae in rice seed. Scientific Reports, 11. doi:10.1038/s41598-020-80644-z
• Product scope and dose statements for Yaduka Agrotech Limited formulations are taken from the company's CIB&RC Section 9(4) registration certificates, labels and leaflets. Where certificate and leaflet differ on crop scope, the certificate's specific condition governs.