Abstract:
Screening for rice varieties with desirable plant architectural traits is a crucial step tn
successful rice breeding. Main objective of this research was to determine variation of
morphological characters at fifth leaf stage and flowering time of selected Sri Lankan
traditional rice accessions during yala season 2024 in Batticaloa district, Sri Lanka.
Two weeks old rice accessions (4132, 5530, 4387, 4237, 4290, 4145, 4772, 473I, and
6412) along with new improved variety Bg 300 were planted in Completely
Randomize Design with five replicates. Days to fifth leaf (DFL), Plant Height (PH),
Number of leaves per plant (lt{L), Flag leaf length (FLL), Flag leaf width (FLW) and
Number of culm O{C) at fifth leaf stage and Days to Flowering (DF) were collected.
One way ANOVA and Principal Component Analysis (PCA) followed by hierarchical
cluster Analysis (HCA) were performed by using Minitab 17 version. There is a
significant difference in DFL, with accession 4145 reported minimum DFL (23.60 +
1.40 days), while Bg 300 maximum DFL (39.40 + l.9l days) of tested rice accessions
(P< 0.05). There is a significant variation in plant height at DFL was noted, with
accession 4145 being the highest (47.42 + 3.05 cm) and Bg 300 the shortest (29.52 +
2.37 cm) (P< 0.05). Significant differences were reported in flag leaf length, with
accession 5530 having the longest flag leaves (40.30 + 1.87 cm) and Bg300 the
shortest (20.30 + 2.18 cm). Among tested ten accessions, only two accessions, 4237
and Bg300 flowered within the experimental period of 105 days. Accession 4237
flowered at (56 + 3.30 days), while Bg300 flowered at (91 + 2.36 days).In analyzing
the clustering of rice accessions based on morphological characters using PCA and
HCA, distinct patterns of similarity have emerged within the different clusters.
Accessions 4731 and 6412 formed a closely related cluster, indicating a high degree
of similarity in PH, NL, FLL, FLW and CN. Similarly, accessions 4132, 4387, and
5530 grouped together, reporting shared phenotypic traits that suggest common
genetic or environmental effects. The accessions 4237, 4290, 4145, 4772, and Bg 300
exhibited broader phenotypic variation but still formed a larger, more diverse cluster.
The similarities that have been noted within these clusters highlight possible
directions for focused breeding initiatives that aim to improve desired features among
related accessions.
