Abstract
This paper focuses on the yield prospects of wheat, rice and maize since these cereals dominate human diet, and since continued yield growth is considered the major route to meeting future global demand for food, feed and fuel. We define for a region farm yield (FY), attainable yield (AY, as reached with the best technology and prudent economics), and potential yield (PY, yield with the best varieties and agronomy and no manageable biotic or abiotic stresses). FY progress is a function of progress in PY and in closing the gap between PY and FY (we express this gap as a % of FY). Globally wheat and rice annual yield increases (as a % of current yield) are falling and are now just below 1%, while that for maize is 1.6%. For rice and wheat, the growth of yields in absolute terms (kg/ha/year) are also falling in developing countries. Global demand modelling to 2050 predicts large real price sensitivity to yield growth rates, with significant price increases if current rates cannot be increased. FY, PY and yield gaps are examined in more than 20 important “breadbasket” regions around the world. For wheat annual PY progress currently averages about 0.5%, and the yield gap 40% (range 25 to 50%), while for rice PY growth is also about 0.5% while the yield gap averages 75% (range 15 to 110%). Maize is distinctive with a current average PY growth of around 1% and a yield gap which ranges from around 30% (Iowa, some uncertainty with PY) to over 200% (sub Saharan Africa). A yield gap of 25% or less probably implies that FY is approaching attainable yields, AY. Yield gaps tend to be larger in developing countries, and seem to be closing only slowly except in the case of maize in Iowa and major cereals in Egypt. Prospects for yield gap closing are discussed. A multitude of constraints can reduce FY, ranging from infrastructural and institutional ones bearing upon farm gate costs and prices and farmer skills and attitudes, to diverse technical constraints. The resolution of the latter in turn depends largely on agronomic and breeding interventions (e.g., better resistance to biotic stresses), though these must be resolved in concert with the other constraints if they are to have significant impact in resource-poor farmers’ fields. Yield gap closing must be a priority for maize in sub Saharan Africa. Prospects for PY increase are discussed. PY gain is increasingly related to greater biomass production, implying greater efficiency of utilization of solar radiation. Recent progress appears to have raised this efficiency, while the theoretical limit still appears to leave scope for further increase. In addition PY in water-limited situations (PYw) will depend on further harvest index increase. In rice and wheat heterosis offers prospects for yield gain. We remain sceptical of the medium term prospects of genetic modification (GM) for yield per se, especially PY, but recognize that existing GM crops often deliver higher yields because of gap closing benefits (such as reduced pest losses). New molecular tools for selection show promise for increasing breeding efficiency, but the marginal cost of yield gains is likely to rise. Strong private investment in breeding, as seen with maize, could play a bigger global role, accompanied by facilitating policies. . We recognize in addition the importance of input efficiency and total factor productivity (TFP) for determining real prices, while prices of non-renewables (energy for traction and N fertilizer; phosphorus) are a relevant concern. TFP in agriculture continues to grow, and many examples confirm the general synergy amongst modern input technologies that achieve not only greater yield but also greater resource use efficiency (e.g., N, P, water, fuel, labour). There are also large gaps in input use efficiency that offer much scope for improved crop and resource management to deliver more with less. Investments in R&D, farmers’ information and skills, and good policy drive this process, and will determine future success or failure.
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Claims 18
Claim · model-written summary
Global wheat and rice yield growth has fallen below 1% annually.
- Taxon
- wheat
Triticum aestivume0 - Outcome
- annual yield increasese0
- Direction
- fallinge0
- Value
- just below 1%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Globally wheat and rice annual yield increases (as a % of current yield) are falling and are now just below 1%”
Claim · model-written summary
Maize annual yield increase is 1.6%.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Globally wheat and rice annual yield increases (as a % of current yield) are falling and are now just below 1%, while that for maize is 1.6%.”
Claim · model-written summary
Absolute yield growth in developing countries is falling for rice and wheat.
- Taxon
- rice
Oryza sativae0 - Outcome
- growth of yields in absolute termse0
- Direction
- fallinge0
- Setting
- developing countriese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For rice and wheat, the growth of yields in absolute terms (kg/ha/year) are also falling in developing countries.”
Claim · model-written summary
Wheat potential yield progress averages 0.5%.
- Taxon
- wheatTriticum aestivume0
- Outcome
- annual PY progresse0
- Value
- about 0.5%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For wheat annual PY progress currently averages about 0.5%”
Claim · model-written summary
Wheat yield gap averages 40%, ranging 25–50%.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- yield gape0
- Value
- 40%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the yield gap 40% (range 25 to 50%)”
t0“For wheat annual PY progress currently averages about 0.5%”
Claim · model-written summary
Rice potential yield growth is about 0.5%.
- Taxon
- riceOryza sativae0
- Outcome
- PY growthe0
- Value
- about 0.5%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for rice PY growth is also about 0.5%”
Claim · model-written summary
Rice yield gap averages 75%, ranging 15–110%.
- Taxon
- riceOryza sativat0
- Outcome
- yield gape0
- Value
- 75%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the yield gap averages 75% (range 15 to 110%)”
t0“for rice PY growth is also about 0.5%”
Claim · model-written summary
Maize potential yield growth averages around 1%.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize is distinctive with a current average PY growth of around 1%”
Claim · model-written summary
Maize yield gaps range from around 30% in Iowa to over 200% in sub Saharan Africa.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a yield gap which ranges from around 30% (Iowa, some uncertainty with PY) to over 200% (sub Saharan Africa)”
e1“Maize”
Claim · model-written summary
Yield gaps are larger in developing countries and close slowly except in Iowa maize and Egypt cereals.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield gaps tend to be larger in developing countries, and seem to be closing only slowly except in the case of maize in Iowa and major cereals in Egypt.”
Claim · model-written summary
Yield gap closing is a priority for maize in sub Saharan Africa.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield gap closing must be a priority for maize in sub Saharan Africa.”
Claim · model-written summary
Potential yield gain is increasingly linked to biomass and radiation use efficiency.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- PY gaine0
- Direction
- increasinglye0
- Qualifier
- greater biomass productione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PY gain is increasingly related to greater biomass production, implying greater efficiency of utilization of solar radiation.”
t0“yield prospects of wheat, rice and maize”
Claim · model-written summary
Water limited potential yield depends on further harvest index increases.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- PY in water-limited situationse0
- Qualifier
- harvest index increasee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PY in water-limited situations (PYw) will depend on further harvest index increase.”
t0“yield prospects of wheat, rice and maize”
Claim · model-written summary
Heterosis offers yield gain prospects in rice and wheat.
- Taxon
- riceOryza sativae0
- Outcome
- prospects for yield gaine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In rice and wheat heterosis offers prospects for yield gain.”
Claim · model-written summary
Existing GM crops often have higher yields through closing yield gaps.
Verbatim
e0“existing GM crops often deliver higher yields because of gap closing benefits (such as reduced pest losses).”
t0“existing GM crops often deliver higher yields”
Claim · model-written summary
Molecular selection tools show promise for increasing breeding efficiency.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- breeding efficiencye0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“New molecular tools for selection show promise for increasing breeding efficiency”
t0“yield prospects of wheat, rice and maize”
Claim · model-written summary
Agricultural total factor productivity continues to grow.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- TFP in agriculturee0
- Direction
- continues to growe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“TFP in agriculture continues to grow”
t0“yield prospects of wheat, rice and maize”
Claim · model-written summary
Modern input technologies can increase yields and resource use efficiency together.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- greater yielde0
- Direction
- greatere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“modern input technologies that achieve not only greater yield but also greater resource use efficiency”
t0“yield prospects of wheat, rice and maize”