Facing the ecology of Green Revolution rice

The controversy around the System of Rice Intensification and its consequences for future rice

improvement strategies

menu

• Rice cultivation: conventional and SRI

methods

• The SRI controversy

• The historical legacy of IRRI

• Conclusion/prospects

Rice cultivation

• Conventional methods: consider plant growth set mainly by genetic potential

– Transplanting after 15-30 days, 2-3 seedlings/hill

– Permanently flooded fields

– Application of fertilizer and pesticide

Rice cultivation

• SRI: consider growth to be set by root development and soil system performance

– Transplanting after 8-12 days, single seedling/hill

– Alternately flooding and drying the field

– Compost and weeding/soil aeration

Conventional transplanting

SRI transplanting

SRI field one week after transplanting

SRI field 7 weeks after transplanting

The controversy

• Main claims from SRI proponents:

– Yield potential (on-farm) similar to or higher than HYVs (on-station)

– New research agenda, stresses on-farm experimentation and root-plant interaction

The controversy

• Main response from IRRI-related researchers

– Yields reported are not proven and unlikely

– All the necessary (theoretical) knowledge on rice is already attained

The controversy

Year Journals Main authors Affiliation

Posi-tive

2002, 2005-07

Agric. Systems, Field Crops Research, TAA Newsletter, IJAS

Stoop, Kassam, Uphoff

Free-lance, FAO, CIIFAD (Cornell University)

Neu-tral

2004 Nature Surridge News editor Nature

Nega-tive

2004-07 Agric. Syst., Field Crops Research, TAA Newsletter

Sheehy, Dobermann, Cassman, McDonald, Lenné

IRRI, U of Nebraska, Cornell University, Univ. of Greenwich

The controversy

• Some triggers and causes:– Wide exposure in practice and in science

(Nature publication) – a competitor/alternative for the Green Revolution-genetic strategy?

– Yield claims exceed conventional crop (theoretical) models

– Network effects and institutional thinking

The historical legacy of IRRI

• IRRI is known for ‘genetic fix’– But genes need an environment to express in

traits (GxE)

• The E-component is focus of physiology and agronomy– Physiology: energy conversion, nutrient

uptake, growth stages– Agronomy: plant density, fertilizer application,

cropping calender

The historical legacy of IRRI

• GxE interaction studied through (cybernetic) crop models

– Colin Donald (1968): ideotype breeding

– Ideotype: plant design based on the model’s optimum outcome

– Models are calibrated on experimental plots

Conclusion

• Rice ecology in IRRI (and partner institutes) works to a (genetic) optimum– Physiologic and agronomic processes serve

the ideotype

– In-field and between-field variation is largely ignored

– Only the top can be on top

Prospects

• More lateral approaches (like SRI) are hard to stop

• Biotech is not the spark for a new GR

• New IRRI is a knowledge bank and training centre