Physiological and biochemical responses of chromosome segment substitution lines of rice to moisture stress and association of root traits with molecular markers

Abstract

A set of 96 lines, including 80 CSSLs, 9 NERICAs, 3 International checks and 4 NRRI newlinechecks in replicated trials were evaluated under vegetative (dry and wet seasons of 2013) and newlinereproductive stage (dry and wet seasons of 2013 and 2014) moisture stress and well watered newlineconditions at National Rice Research Institute (NRRI), to identify stress tolerant lines. newlineDrought sensitivity at vegetative stage which was observed on basis of leaf rolling newline(LR), leaf drying (LD) and drought recovery (DR) following the standard evaluation system newline(SES) of International Rice Research Institution (IRRI, 2002) during the moisture stress period newlineand early vegetative vigor (EVV) scored at 30 days seedling stage. Among 80 CSSLs and 9 newlineNERICAs (excluding 7 checks), at 14 days of stress period (DSP), 24 lines in dry season and newline17 lines in wet season showed less symptoms and low scores of LR and LD with early DR newlineresponse. Based on preliminary screening of both dry and wet seasons, 17 lines; RUF-2, RUF newline10, RUF-16, RUF-41, RUF-42, RUF-44, MER-14, MER-16, MER-20, MER-24, MER-32, newlineNERICA-1, NERICA-3, NERICA-5, NERICA-8, NERICA-9 and NERICA-11 with low newlinescoring of LR and LD were found common and identified as drought tolerant lines at vegetative newlinestage stress. The soil moisture content (SMC) during the stress period was 11.13% and 14.10% newlinein dry and 9.83% and 11.65% in wet season at 15 and 30cm soil depth respectively, while the newlinesoil moisture tension (SMT)/ soil matric potential (SMP) was recorded -53 kPa and -45 kPa in newlinedry and -57 kPa and -51.5 kPa in wet season at the same soil depth. newline newlineAt reproductive stage, drought tolerant index like relative yield reduction (RYR) and newlineagro-morphological traits responses were employed in the screening of lines. The variation in newlineRYR among the 20 lines ranged from 33.98 to 82.12%, 32.71 to 70.62%, 64.67 to 83.41% and newline32.14 to 73.21% in dry and wet seasons of 2013 and 2014. Significant yield reduction was newlineobserved under moisture stress in all the lines studied. Moisture stress at reproduct