Effects of drought stress on grain yield and qualitative characteristics of three populations of Lallemantia royleana Benth

This research was aimed to investigate the effects of drought stress on grain yield and qualitative characteristics of three populations of Lallemantia royleana Benth. The study was conducted in the research farm of Collage of Agriculture of Shahed University. This study was conducted in a split plot based on randomized complete block design (RCBD) with three replications during 2013-2014. The experimental factors consisted of four levels of drought stress as the main plots including control or soil water potential (SWP) of -0.5atm as field capacity (FC), soil water potential (SWP) of -3.5 atm as moderate stress, soil water potential (SWP) of -6.5 atm as relatively sever stress, and soil water potential (SWP) of -9 atm as severe stress. The Balangu populations including Mashhad, Kerman, and Taleghan were considered as sub-plots. The traits measured included grain yield, total chlorophyll, chlorophyll a, chlorophyll b, carotenoids, mucilage percent, turgor factor, and proline content. The results showed that the population and the interaction of drought stress and population had significant effects on chlorophyll a, total chlorophyll, proline and grain yield at the 1% level. The effect of drought stress was found to be significant on grain yield, photosynthetic pigments, leaf proline content (P