A major terminal drought tolerance QTL of pearl millet is also associated with reduced salt uptake and enhanced growth under salt stress

The performance of a major quantitative trait locus (QTL) of terminal drought tolerance (DT) of pearl millet was assessed under salt stress. The test-cross hybrids of the QTL donor parent (drought tolerant, PRLT 2/89-33), QTL recipient parent (drought sensitive, H 77/833-2), and a set of six near isogenic lines introgressed with a terminal DT-QTL (QTL-NILs) were evaluated for germination and seedling emergence at 7 days after sowing (DAS) in Petri plates at four salinity levels, and at vegetative (24 DAS) and maturity stages at three salinity and alkalinity levels. Na+ and K+ accumulation, their compartmentation in different plant parts, and their effects on growth and yield parameters were evaluated. The DT-QTL donor parent and QTL-NILs accumulated less Na+ in shoot parts at seedling, vegetative and maturity stages, and also partitioned the accumulated Na+ more into nodes and internodes and less into leaves than the drought-sensitive recurrent parent. The pattern of reduced salt accumulation in the drought-tolerant parent and QTL-NILs was consistently associated with better growth and productivity in saline and alkaline treatments. It is concluded that the DT-QTL contributed by PRLT 2/89-33 exerted favourable effects on growth and productivity traits under salt stress by limiting Na+ accumulation in leaves.