Abstract:
Rice is one of the most studied plants due to high genetic variation and being the major food
for more than half of the world population. Sri Lankan traditional rice varieties are rich in genetic
diversity and important characteristics. Before studying the genetic background of characters, a
preliminary study on morphological characters is needed. This study was aimed to evaluate
variability of selected Sri Lankan traditional rice varieties with respect to morphological
characters. Seeds of 24 Sri Lankan traditional rice varieties and IR64 were selected. A pot
experiment with complete randomized bock design was used and five replicates were prepared.
Fifteen characters were measured using standard evaluation system for rice and descriptors for
rice, published by International Rice Research Institute and analyzed by multivariate analyzing
tools using principal component analysis (PCA) and single linkage cluster method provided by
IBM SPSS 16.0 statistical software. Selected rice varieties were grouped into 5 clusters at 15
minimum distance between clusters. Cluster I comprises twenty one varieties and other four
clusters comprise single variety in each. Clustering of 21varieties (Goda heenati, Thawalu, Al wee,
Goda el wee, Pachchaperumal, Godamanel, Goda wee, Kottiyaran, Kara el, Batapola el, Pokkali,
Hetada wee, Moddai karuppan, Vannam villai, Kalu heenaty, Sudu heenaty, Pola el, Kalu bala
wee, Kahatawalu, Dahanala and Niyan wee) into one cluster shows the homology of the varieties.
Clustering of IR64, Gonabaru, Rathl and Ma wee in different clusters indicates their significant
difference from cluster I. Five principle components (PCs) were identified as significant according
to PCA. They account for 79% of total variation. PC1 accounts for 30% and PC1 and PC2 together
account for 51% of variance. Selected varieties show a significant difference according to the
clustering pattern. Out of descriptors used in this study, significant descriptors of PC1 to PC5 can
be used to differentiate selected varieties.
