Salt stress—both salinity and alkalinity/sodicity—is a worsening problem in inland areas in Sub-Saharan Africa such as in Mali, Ethiopia, and Burundi due to the buildup of salt as a consequence of the excessive use of irrigation water with improper drainage, coupled with the use of poor-quality irrigation water or sodic soils developed from salt-bearing rocks. Salt-affected areas are predominantly inhabited by impoverished communities with fewer opportunities for food security and livelihood options.
As much as one-third of the rainfed lowland areas in Sub-Saharan Africa are thought to be affected by submergence. Modern rice varieties are not adapted to these conditions. Farmers in the subregion suffer from either regular yield loss when they grow these varieties, or low yield when they continue to cultivate local landraces.
Low germination under anaerobic conditions
Rice usually has low germination under anaerobic conditions, which leads to a poor crop stand in direct seeded rice cultivation when rain occurs after seeding. Most modern rice varieties either fail completely to germinate underwater or fail to elongate the coleoptile and develop roots and shoots for further development under a long period of oxygen deprivation. This results in partial to complete crop failure. Thus, the development of varieties able to tolerate flooding during germination—referred to as anaerobic germination—is critical for DSR in both rainfed and irrigated ecosystems.
Our solutions in a nutshell
The ClimateSmart African Rice project team will identify novel genes or QTLs involved in flood or salinity tolerance of rice using African rice germplasm such as Oryza glaberrima and wild relatives.
The underlying knowledge gaps for achieving the overall objective are the following:
the role of the root barrier to radial O2 loss (ROL) in protecting against tissue intrusion of soil phytotoxins and salt (NaCl);
the genotypes and role of superhydrophobic leaf cuticles resulting in the formation of leaf gas films during submergence and the consequences for sustaining gas exchange and protecting against salt intrusion; and
the prevalence of the trait of anaerobic germination
The scientists in the team propose to use promising genotypes of wild relatives from wetland habitats to uncover these trait capacities.