Abstract:
Scarcity of water for irrigation is an alarming issue limiting crop production worldwide and it is
increasing severely in Sri Lanka. The rice yield is highly susceptible to moisture stress especially
during the ‘Yala’ Season. This study therefore was made to evaluate moisture stress tolerance of
selected rice cultivars viz; ‘Bg300’,’Bg357’,’Bg366’,’Bw367’ and ’Bg370’. Randomized complete
block design with ten treatments and four replications were used in this study. The treatments
were arranged in 5 × 2 factor factorial manner. Moisture stress was imposed for the selected rice
cultivars for a period of fourteen days during the panicle initiation stage. The control plants
were watered once in two days. Moisture stress significantly (p<0.05) reduced the Relative
Water Content (RWC) of all the tested rice cultivars. The highest RWC (59.2%) was observed in
‘Bg370’ rice cultivar and the lowest (48.2%) was found in ‘Bw 367’ under moisture stress
condition. Moisture stress significantly (p<0.05) reduced Chlorophylls a, b and total Chlorophyll
contents of the tested rice cultivars. The highest amounts of Chlorophylls a (9.1mgg-1), b
(9.8mgg-1) and total Chlorophyll (13.3 mgg-1) were observed in ‘Bg370’ rice cultivar and the
lowest amounts (Chlorophylls a-4.5mgg-1, b-4.5mgg-1 and total Chlorophyll-6.3mgg-1) were
recorded in ‘Bw367’. Moisture stress significantly (p<0.05) reduced the Leaf Area Index (LAI) of
all the tested rice cultivars. The highest LAI (0.9) was observed in ‘Bg370’ and the lowest was
found in ‘Bw367’ under moisture stress. Moisture stress significantly (p<0.05) reduced the yield
of all the tested rice cultivars. The highest yield (2.1tonnesha-1) was observed in ‘Bg370’ rice
cultivar and the lowest (0.5 tonnesha-1) was found in ‘Bw367’ under moisture stress. Hence,
Cultivar ‘Bg370’ exhibited comparatively more tolerance to moisture stress with less reduction
in various physiological and growth attributes and could be suggested for cultivation in the
drought prone areas of the Batticaloa district
