Salinity is an ever-present threat to crop yields, especially in countries where …

• Abstract
• Why should we want to improve crop salt tolerance?
• Historical perspective
• The complexity of salt tolerance
• Approaches to enhancing tolerance
• Conclusions
• Supplementary data
• References
• Tables

Biology Articles » Agriculture » Plant Production » Improving crop salt tolerance » Why should we want to improve crop salt tolerance?

Why should we want to improve crop salt tolerance?

- Improving crop salt tolerance

Earth is a salty planet, with most of its water containing about30 g of sodium chloride per litre. This salt solution has affected,and continues to affect, the land on which crops are, or mightbe, grown. Although the amount of salt-affected land (about900x10⁶ ha) is imprecisely known, its extent is sufficient topose a threat to agriculture (Flowers and Yeo, 1995; Munns, 2002)since most plants, and certainly most crop plants, willnot grow in high concentrations of salt: only halophytes (bydefinition) grow in concentrations of sodium chloride higherthan about 400 mM. Consequently, salinity is a threat to foodsupply. Although there is currently food enough for the worldpopulation, more than 800 million people are chronically undernourished(Conway, 1997). Growth of the human population by 50%, from6.1 billion in mid-2001 to 9.3 billion by 2050 (http://www.unfpa.org/swp/2001/),means that crop production must increase if food security isto be ensured, especially for those who live on about $1 perday.

Approximately half of the world’s land surface is ‘perennialdesert or drylands’ (United Nations Development Programme,see http://www.undp.org/seed/unso/pub-htm/dryland-population.pdf).These areas can only be made more productive by irrigation (andirrigation increased by almost one-third between 1979 and 1999,from 207 to 274 million hectares; http://apps.fao.org/page/collections?subset=agriculture).Unfortunately, a strong link with salinization (Ghassemi etal., 1995), throws an immediate question over the sustainabilityof using irrigation to increase food production and it has beenargued elsewhere (Shannon and Noble, 1990; Flowers and Yeo, 1995)that the primary value of increasing the salt toleranceof crops will be to the sustainability of irrigation. Giventhe amount by which food production will have to be increased,it seems reasonable to predict that changing the salt toleranceof crops will be an important aspect of plant breeding in thefuture, if global food production is to be maintained.