Effect of drought on morpho-physiological, yield and yield traits of chromosome segment substitution lines (CSSLs) derived from wild species of rice

Eighty chromosome segment substitution lines (CSSL) developed in the background of Curinga x O. rufipogon and Curinga x O. meridionalis along with four checks (tolerant and susceptible) were subjected to vegetative and reproductive stage drought stress. At vegetative stage, drought stress significantly reduced total chlorophyll content, relative leaf water content with an increase in proline content. RUF-44, MER-13 and MER-20 were found promising with consistent performances in various morpho-physiological observations. The higher accumulation of proline, more chlorophyll retention and more relative leaf water content at vegetative stage during moisture stress were major criteria for stable yield production of drought tolerant CSSLs. At reproductive stage stress, the CSSLs with high grain yield, minimal relative yield reduction (RYR) and lowest susceptibility index (DSI) were considered as drought tolerant and the reverse as susceptible line. RYR and DSI along with high grain yield under moisture stress was observed in MER-20 and MER-13 with 81.84% and 8.35% RYR and 0.83 and 0.11 DSI values in dry and wet seasons, respectively. However, the extent of RYR was maximum with high DSI in IR 20 and Curinga in both the seasons.