0735 Facing the Ecology of Green Revolution Rice: The Controversy Around the System of Rice...
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Transcript of 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