Pearl Millet Mapping Population Parents: Performance and Selection Under Salt Stress Across Environments Varying in Evaporative Demand

Abstract

It is vital to screen the germplasm of crop plants for salt stress tolerance so as to utilize them in breeding programs. Accordingly, in the present study, twenty diverse inbred lines, parents of mapping populations of pearl millet were chosen to determine the phenotypic contrasts for seed yield, which can open the way for developing salt tolerance QTLs. Parents were grown in two summer seasons (late and early) with VPD ≥ 2 kPa, and one rainy season with VPD < 2 kPa, during flowering and grain filling under saline (150 and 200 mM) and non-saline (0 mM) conditions. Salinity delayed flowering time by a fortnight in the summer seasons but only 5–6 days in the low VPD rainy season. Salinity decreased grain yield by 86% in late-summer and 80% in early-summer, but less than 70% in rainy season. GY penalty was higher than vegetative biomass under saline conditions especially in summer season when the evaporative demand was very high. It appears that reproduction and grain filling are sensitive to high temperature that can compound the effect of salinity and high VPD. GY of inbreds under salinity was not better in comparison with non-saline conditions. DOF and grain density (thousand grain weight) were found as important correlated traits under salinity. Also, GY was affected significantly if VPD increased during flowering time.