High-yield varieties, and the Green Revolution's bill
Breed and supply short-strawed, high-yielding cereal varieties with the fertilizer and water they need, and pay their known costs up front: metered groundwater, no highly hazardous pesticides, a gene bank for the varieties they replace, and nutrients bred back into the staples.
Everything for this step
- Field guide
- Sustainable farming → 9 sections Biology → 19 sections
- Builds
- None yet.
- Reference sheets
- 1 sheet in Sustainable farming
- Sciences it rests on
- Genetics · Agricultural science · Earth sciences
- Track
- Crops and soil, level 6 of 7 · next: Sustainable intensification
Why this matters
Between 1960 and 2000, yields in developing countries rose 208 % for wheat, 109 % for rice and 157 % for maize; over 50 years cereal production tripled while the cultivated area grew only 30 % (Pingali, PNAS, 2012). The package was high-yielding varieties with fertilizer, irrigation and, to some extent, pesticides. IR8, the first effective semi-dwarf rice, released by IRRI on 28 November 1966, carries a single recessive gene for shortness, sd-1 (IRRI): a short, stiff straw that holds up a heavy, fertilized head.
The bill came with it. In northern India more than 108 km³ of groundwater disappeared between 2002 and 2008, pumped mostly for irrigation, with levels falling up to 33 cm a year (NASA JPL). Pesticides are used in 14–20 % of suicide deaths worldwide (Our World in Data). Some 75 % of crop genetic diversity has been lost since 1900 as farmers replaced local varieties with uniform high-yielding ones (FAO). Each cost has a known rule against it.
The shape of it
- Breed a short, stiff straw that carries a heavy head on fertilizer without falling over: the semi-dwarf genes of IR8 rice (sd-1, 1966) and of the high-yielding wheats.
- Test against the best local variety at several sites over several seasons before release, and publish the results.
- Multiply seed through pre-basic, basic and certified classes, with field inspection for varietal identity and purity (OECD Seed Schemes).
- Supply the whole package or none of it: the new varieties pay only with the fertilizer and water they were bred for.
- Meter groundwater and cap pumping at the recharge; northern India lost 108 km³ in six years.
- Ban highly hazardous pesticides; Sri Lanka's bans from 1995 cut suicides with no sudden fall in yields.
- Bank the landraces before they are replaced, with a safety duplicate, as 1.37 million samples are in Svalbard.
- Breed iron, zinc and vitamin A back into the staples.
Doing it, step by step
The summary above says what has to happen. This says how, with the numbers that decide whether it works.
1 · Breed the short straw
A tall traditional variety given heavy fertilizer grows more straw and falls over (lodges) before harvest. The breakthrough was a shorter, stiffer plant that puts the extra growth into grain:
- Rice: IR8, released by IRRI on 28 November 1966, from a cross of the dwarf Taiwanese Dee-geo-woo-gen with the tall Indonesian Peta; its shortness comes from a single recessive gene, sd-1 (IRRI).
- Wheat: semi-dwarf wheats bred at CIMMYT in Mexico played the same part (Pingali, 2012).
Breed from the best local material as one parent wherever possible, so the new variety keeps the local grain quality, disease resistance and season length.
2 · Test at several sites, against the best local variety
A variety that wins at the research station can fail on farms. Before release, grow each candidate beside the best variety farmers already use, at several sites that represent the region's soils, rainfall and altitudes, for several seasons, in replicated, randomised plots so that chance differences between plots can be told from real ones.
Release only varieties that beat the local standard across most sites and seasons, and publish every result, the failures included.
3 · Multiply seed in certified classes
A good variety is only as good as the seed farmers can buy. The OECD Seed Schemes recognise three classes:
- Pre-basic (breeder's) seed, held by the breeder and used only for further multiplication.
- Basic (foundation) seed, grown only to produce certified seed.
- Certified seed, the class sold to farmers.
Each multiplication crop is inspected in the field for varietal identity and purity, and off-types are pulled before harvest; a control plot grown from each seed lot confirms it is true to variety.
4 · Supply the whole package
The high-yielding varieties were one part of a package: fertilizer, irrigation and, to some extent, pesticides were critical components (Pingali, 2012). Planted without them they give little advantage.
- Nitrogen from synthetic fertilizer, applied to a soil test and a nutrient budget rather than by the bag.
- Water applied by measured irrigation, not by flooding at every chance.
- A rotation with a legume, so the field does not become a cereal monoculture.
5 · Meter the groundwater and keep pumping within recharge
Wells and cheap pumps made the high yields possible and then drained the aquifers. NASA's GRACE satellites measured more than 108 km³ of groundwater lost from Haryana, Punjab, Rajasthan and Delhi between 2002 and 2008, with levels falling by up to 33 cm a year, pumped mainly for irrigation; the region's 114 million residents face shortages of water and farm output if it continues (NASA JPL).
- Measure water levels in a network of observation wells, every year at the same season.
- Meter every irrigation well and charge for water or power by the unit, not by a flat rate.
- Cap total pumping at the aquifer's measured recharge, and favour crops and methods that need less water.
6 · Ban the highly hazardous pesticides
Pesticides are used in 14–20 % of suicide deaths worldwide, some 100,000–150,000 deaths a year (Our World in Data). Sri Lanka banned WHO Class I pesticides in 1995, endosulfan in 1998 and later paraquat; suicide deaths fell from about 7,440 in 2000 to 3,175 in 2021, and there was no sudden drop in yields after any of these bans (same source).
Keep a register of approved pesticides, refuse WHO hazard Class Ia and Ib products, and follow the farming guide on safe use, storage and protective equipment.
7 · Bank the landraces before they disappear
Some 75 % of plant genetic diversity has been lost since the 1900s as farmers left local varieties for uniform high-yielding ones (FAO). That diversity holds the genes for the next disease or drought.
- Collect the local varieties and wild relatives before they are replaced, with their place and growing notes.
- Store them dried and cold in a national gene bank, and regrow and test each sample before its seed loses viability (seed guide).
- Duplicate every collection abroad: in 2025 gene banks deposited more than 46,000 samples in the Svalbard Global Seed Vault, bringing it to more than 1.37 million (Crop Trust).
8 · Breed the nutrients back in
Diets that narrow to one or two high-yielding cereals can supply enough calories and too little iron, zinc and vitamin A (nutrition). Biofortification breeds those nutrients into the staples themselves, so they reach people who cannot buy a varied diet: HarvestPlus works on 13 staples bred for iron, zinc and vitamin A, iron beans among them, and counts 651 million people eating biofortified food in 2024 (HarvestPlus).
Plant pulses and vegetables in the rotation as well: biofortification adds to a varied diet, it does not replace it.