Abstract:
Photoperiod is a major environmental factor regulating vegetative development in
traditional Sri Lankan rice varieties. Yet limited scientific evidence exist on how
kuruluthuda rice (Accessions number,3549) response to controlled light duration. the
knowledge gap restricts the development accurate guideline for optimizing planting
time and improving growth performance. The present study evaluates the influence on
different photoperiod level on vegetative growth on kuruluthuda using completely
Randomized design (CRD)with six photoperiod treatments (8h,9h,10h,1 1,1 t h,45 min,
and natural day length l2h20min). Each treatment has five replicates. The experiment
was conducted from 29 July to 2 September 2025.Plant height, leaf length, leaf width
and number of tillers were recorded and analysis one -way ANOVA at the 0.05
significance level. And day length showed minimal variation during the experimental
period. The findings indicate that, photoperiod had a significant effect on several
vegetative growth traits. The longest photoperiod (T6) produces significantly Higer
plant height (118+3. 62cm. p:0.011<0.05) and the greater leaf length (74.20+6.46cm.p:0.05<0.05). indicating that extend light exposure enhance elongation growth and leaf
expansion. The number of leaves (12.60+0.92cm. p:0.022<0.05) and Number of tiller
(I.60+0.24. p:0.021<0.05) were also higtrest under T6. leaf width showed no
significant among treatment (p:0.11>0.05). suggesting genetic control of this
parameter. Overall, the results show that kuruluthuda rice exhibits a positive vegetative
response to longer photoperiod. Providing essential baseline information for optimizing
planting schedules and light -management strategies aimed at improving growth and
maximizing yield potential.
Key Words: Day length, Kuruluthuda Rice, Photoperiod, vegetative growth
parameters.
