Prognosis for genetic improvement of yield potential and water-limited yield of major grain crops.

By A. Hall, R. Richards. 2013

265 citations recorded by the source corpus.

Abstract Genetic improvement of crop yields under potential (Yp) and water scarce conditions (Yw) will be an important avenue to improved food security over the next four decades, at the end of which projected demand for food, feed and biofuel feedstock is expected to level out. Current measured relative rates of improvement in Yp and Yw for the three main cereal crops (maize, wheat and rice) in many cropping systems in the world are mostly well below the 1.16–1.31% y−1 rates required to meet projected demand for cereals in 2050. These relative rates can be expected to fall further if the current absolute rates of yield improvement continue unchanged and/or the current indications of stagnation in yield improvement for some crops in some regions of the world become widespread. This review assesses the available evidence for unexploited opportunities for enhancing current rates of genetic improvement for Yp and Yw, and examines some substantive proposals for achieving the same end through genetic engineering of photosynthesis, above-ground ideotype design, and improvement of root capacity for water uptake. Because time is of the essence, special attention is paid to the time scales required to progress potentially useful traits through to proof of concept under field conditions, from there to farmer-ready cultivars, and for widespread adoption by farmers of the improved cultivars. The requirements of breeders for inclusion of potentially important traits into the conventional breeding process are outlined and the value of molecular breeding tools as aids to genetic improvement of simple and complex traits is considered. Intellectual property and regulatory requirements are taken as additional potential drags on the rates of adoption into the breeding process of useful traits and/or to the free flow of information between research teams. Main conclusions are: (a) there are some unexploited opportunities to improve Yp or Yw in some crops and/or cropping systems; (b) exploitation of these opportunities could be hastened by increasing funding for focussed research and by identifying and eliminating or reducing drags at various stages of the idea to farmer-ready cultivar chain; (c) the time-scales required for major improvements in yield in farmer-ready cultivars through genetic engineering or ideotype realisation are likely to be measured in decades rather than years; (d) current and expected future relative rates of progress in Yp and Yw are a matter of real concern and are insufficient to meet projected demand for cereals by 2050. Possible step changes in Yp or Yw powered by genetic improvements such as exploitation of hybrid vigour in rice or hypothetical successes in the genetic engineering of photosynthesis are unlikely to change this outlook. The pessimistic assessments embodied in the last two conclusions should not obscure the fact that without continued investment in the search for sources of genetic improvement and development of aids to breeding, the unmet demands for cereals in 2050 will be even greater.

Subfields: Agronomy and Crop Science, Plant Science

View Paper: https://www.semanticscholar.org/paper/b0d346e6e69b1323e5a561ab2073cb1f452279ab

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Citations in the corpus

The U.S. drought of 2012 in perspective: A call to action (2013, background): “Innovations in crop production have typically taken up to 20 years from discovery to proof-of-concept and even longer for widespread farmer adoption (Hall and Richards, 2012); many important food crops have received relatively limited attention (Varshney et al.”
Industry-Scale Evaluation of Maize Hybrids Selected for Increased Yield in Drought-Stress Conditions of the US Corn Belt (2015, background): “, 2013); decades-long periods between inception and farmer implementation of innovations; lack of infrastructure and markets in select regions where large productivity gains are possible; considerations for intellectual property rights; and inconsistent global regulations (Hall and Richards, 2012).”
Breeding for increased nitrogen‐use efficiency: a review for wheat (T. aestivum L.) (2016, background): “Root architecture and root function are likely to be multigenic and hence much more difficult to select for (Hall and Richards 2013).”
Physiological responses of wheat to drought stress and its mitigation approaches (2018, background): “Plant breeding for enhanced water productivity is crucial to fulfilling increasing food demand due to water-deficit conditions in agriculture that will reduce food security in coming years (Davies and Bennett 2015; Hall and Richards 2013).”
Yield gap analysis—Rationale, methods and applications—Introduction to the Special Issue (2013, background): “A second review paper considers possibilities for further genetic progress in potential and water-limited crop yields (Hall and Richards, 2013).”
Fruiting efficiency: an alternative trait to further rise wheat yield (2015, background): “It may be required that yield of wheat (and other major crops) be increased by at least 50% in the next few decades (Reynolds et al. 2009 ), which will depend on improving yield potential (Fischer and Edmeades 2010 ; Hall and Richards 2012 ).”
Characterization of the main chickpea cropping systems in India using a yield gap analysis approach (2018, background): “By contrast, cropping system productivity under dynamic GxExM scenarios can be reasonably well captured using system-crop modelling tools (Hall and Richards, 2013; Grassini et al., 2015).”
Optimizing dry-matter partitioning for increased spike growth, grain number and harvest index in spring wheat (2019, background): “However, the rates of yield gains required to meet predicted global59 demand for cereals in 2050 are higher than the present rates of genetic gains at ca. 1.16% - 1.31% per60 annum (Hall and Richards 2013).”