Abstract
Experiments were performed to assess drought related traits and genotypes under
drought condition. Data on visual leaf rolling and drying at vegetative and reproductive
stages of 50 rice genotypes were scored following standard evaluation system (SES)
grades and identified 7 genotypes viz., RM-40/C-1-1-5, R-3027, W-60, Binadhan-14,
Y-1281, THDB and BRRIdhan56 as drought tolerant. Most of the studied morphophysiological and yield attributing traits showed lower comparative reduction (%) under
drought stress in tolerant genotypes. Of these traits, panicle length and grain yield
showed high heritability, whereas high PCV, GCV and genetic advance were recorded
for plant height and rolled leaf (%). PCA bi-plot separated genotypes in 2 distinct groups
with extreme distances as drought susceptible and tolerant groups. From the tolerant
group (RM-40/C-1-1-5, Binadhan-14, R-3027, W-60 and BRRIdhan56) and susceptible
check Binadhan-7 was selected for further evaluations. Of the selected genotypes, RM40/C-1-1-5, R-3027 and W-60 produced lower reactive oxygen species (ROS, O2-and H2O2
than susceptible Binadhan-7 under drought stress. Increased ROS accumulation observed
in the tolerant genotypes but their many folds up-regulation was recorded in susceptible
check Binadhan-7. Tolerant genotypes except Binadhan-14 showed higher antioxidant
activities. Genotypes RM-40/C-1-1-5, W-60 and R-3027 showed higher proline,
chlorophyll, photosynthetic rate and RWC; whereas RM-40/C-1-1-5, R-3027 and BRRI
dhan56 showed lower comparative reduction (%) in root and shoot lengths under stress
than Binadhan-7. Anatomical feature showed larger vascular bundles and out growths in
the tolerant genotypes. Finally, field performance of 6 selected genotypes was assessed at
three drought prone locations in Bangladesh. Genotypes showed significant location
effects and Magura appeared as the most suitable among 3 locations. Susceptible
genotype Binadhan-7 showed drastic reduction (%) yield and yield components
compared to tolerant genotypes under drought stress. Genotypes RM-40/C-1-1-5, R-3027
and W-60 were predicted as drought tolerant genotypes with comparative higher yield,
and could be released immediately or source of plant breeding applications.