ABSTRACT
Towards improving the salt tolerance of soybean Ailin Liu, Wai-Lun Cheung, Wai-Shing Yung, Carol Lee, Fuk-Ling Wong, Kit-Wah Siu and Hon-Ming Lam, The Chinese University of Hong Kong, China
1 Introduction
2 Soybean germplasm resources for salt tolerance
3 Integrating -omic approaches for investigating salt tolerance in soybean
4 Molecular breeding of salt-tolerant soybean
5 Future trends and conclusion
6 Where to look for further information
7 Acknowledgements
8 References
Soybean is one of the major crops worldwide and its production has been impacted by multiple environmental factors, including salinity (Phang et al. 2008). Salinity hampers the growth and yield of soybean by decreasing water efficiency inside the plant cell and it also causes sodium (Na+) and chloride (Cl−) toxicity (Miransari 2015). The world production of soybean is about 260 million tons, utilizing over 100 million hectares of farmland (Anon. 2012b). In 2015, the total area devoted to soybean production in United States was 33.4 million hectares, and its yield reached 3.2 metric ton/hectare (SoyStats: https://soystats. com). Twenty percent of irrigated land, which produces 40% of the world’s food, has been affected by salinity (Pimentel et al. 2004). The yield of soybean decreases when soil salinity exceeds 5 dS/m (Ashraf 1994). Numerous studies have shown that salt stress leads to a reduction of more than 50% in soybean production (Essa 2002; Hosseini et al. 2002). The USDA estimation of the potential economic impact of saline soil on soybean production shows that the annual economic impact on soybeans yield loss was up to US$7.88 million in upper James River, Virginia (Anon. 2012a). Species within the genus Glycine show a spectrum of salt tolerance capacity, with the tolerance threshold to sodium chloride (NaCl) ranging from 3.0 to 17.5 g/L in the perennial Glycine species and ranging from 5.2 to 8.0 g/L in Glycine max cultivars (Lu et al. 2009). As a major food crop, it is crucial to maintain and even improve soybean production, and to achieve this goal within a sustainable agricultural system.
