IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
What is the outlook for genetic improvements in yield potential and water productivity of major food crops in the immediate future?.
Autor/es:
A.J. HALL
Lugar:
Beijing
Reunión:
Taller; Yield Gap Assesment Workshop; 2011
Institución organizadora:
China Agricultural University
Resumen:
The presentation reviews current perspectives for achieving sufficient genetic yield progress to meet forecast (70%) increases in demand for major food grains by 2050, via empirical breeding for yield (EPY), targeted trait-based selection (TTS), and genetic engineering (GE), in both unstressed and water-limited cropping systems. Time required to progress an idea or discovery to field-demonstrated proof of concept and thence to incorporation into farmer-acceptable cultivars is taken into account. Current rates of advance by EPY for stress-free conditions are insufficient, especially in rice and wheat, although use of hybrids in these two crops might provide a one-time boost if the additional cost of the seed could be mitigated. Progress via EPY in rain-fed conditions is slower due to reduced heritability. There are some exploitable yield-augmenting traits that could be used in a phenotype-based TTS process targeting non-stressed environments, but they have yet to be widely incorporated into the breeding process. Traits appropriate to rain-fed conditions have been much explored and a few of these have been incorporated via phenotype-based TTS (molecular markers are not yet robust enough) into current cultivars with a modest effect on yield. Currently, improvement through GE falls in two categories: the use of transgenes or over-expression of single native genomic regions to improve yield under water-limited conditions, and hypothetical blueprints for major re-engineering of the photosynthetic process to increase crop biomass. Limited results obtained using the first route suggests progress of a magnitude comparable to that using phenotype-based TTS. Many genes or genomic regions putatively useful for drought tolerance are unlikely to have great impact because of their emphasis on survival, rather than production, the complexity of yield determination, and the absence of proof-of-concept testing. Major re-engineering of the photosynthetic process via GE remains hypothetical and might take 10-30 years or more to reach the field proof-of-concept stage. None of EPY, TTS, or GE, either singly or in combination, looks likely to ensure yield increases of the magnitude required to cope, within the next 40 years, with the predicted increase in demand for major food grains.