Field hydroponics assessment of salt tolerance in Cenchrus ciliaris (L.): growth, yield, and maternal effect

Abstract

Soil salinity and sodicity have long been major constraints to increasing crop production in many parts of the world. The introduction of salt-tolerant perennial species is one of the most promising alternatives to overcome salinity problems. Cenchrus ciliaris (L.) is a highly drought-tolerant species but there are few available reports on its salt tolerance. The purpose of this work was to assess this trait in two widely used cultivars (Biloela and Texas) and to determine whether cultivation under salinity affected seed germination and plant fitness in the next generation. Trials were performed under field hydroponics conditions. Plants were grown for 5 months in 1000-L PVC boxes containing washed river sand, and were automatically irrigated with a commercial nutrient solution to which NaCl was gradually added to provide to provide average season electrical conductivity (EC) levels of 9, 15, and 19 dS/m. Controls had EC 4 dS/m. Vegetative growth in both cultivars was similarly affected by salinity, and grain yield diminished because of a decreased number of spikelets per plant. Significant growth and yield reductions were registered at EC ~10 dS/m, and growth continued to decrease with a very small slope as salinity increased, indicating that this species has moderate salt tolerance. Salinity decreased seed germination percentage; however, germination was higher in seeds obtained from plants that had been grown under saline conditions for one season. Growth was similar in plants obtained from seeds that originated from non-salinised and salinised plants. These results suggest that persistence of C. ciliaris in saline soils would not be limited by diminishing plant performance but, rather, by grain yield and seed germination.