0735 facing the ecology of green revolution rice: the controversy around the system of rice...

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