Abstract:
A field experiment was conducted during the season of Maha 2017 at the AgroTech Park, South
Eastern University of Sri Lanka which is located in Malwatha, Ampara district of Sri Lanka to evaluate the leaf
stomatal characteristics and its influence on above ground biomass and grain yield of new improved rice
cultivars namely AT 362 and BG 94-1. The experiment was laid out in a Randomized Complete Block Design
(RCBD) with four replicates. Parameters on stomatal conductance, growth characters namely plant height,
number of productive tillers, unproductive tillers and yield contributing characters such as panicle length,
panicle weight and straw weight were recorded. The data obtained were analyzed with paired t-test using
STATA software and further correlation and regression were tested using SPSS. It has been found that
stomatal conductance, plant height and panicle weight were varied significantly (P<0.05) among the tested
varieties. However, productive tillers, unproductive tillers, straw weight and panicle length were not significantly
different (P>0.05) among treatments. At harvesting, the maximum plant height (64.25 cm) was notified in AT
362 and the lowest (56.58 cm) was found in BG 94-1. During reproductive stages, panicle weight was strongly
and positively correlated (r = 0.999) with parameters of stomatal conductance, plant height, productive tillers,
panicle length and above ground dry matter (AGDM). It indicates that about 99.8% variation in panicle weight
could be explained by the variation in evaluated characteristics. Further, linear regression for above ground
dry matter and stomatal conductance showed a non-significant (p>0.05) positive correlation (r = 0.687). The
value of R2 (0.473) indicates that about 47.3% variation in stomatal conductance could be explained by the
variation in AGDM. Meanwhile, AT 362 significantly performed better than the variety BG 94-1 for growth and
yield characters namely panicle length (19 cm), panicle weight (291.5 gm-2) and straw weight (251.3 gm-2).
Thus, the results of various characters studied in the experiment depict that crop yield would be improved
further by altering stomatal properties and ultimately impact the photosynthetic capacity.
