Morphological Variation of Vegetative Phase among Ma Wee (Oryza sativa L.) Accessions during Non-Inductive Growing Season for Flowering

Abstract

Ma wee (Oryza sativa L.) had been a popular traditional rice in the past due to desirable
agronomic traits for adverse environments. Ma wee accessions (Accns) are known to be
photoperiod sensitive for flowering initiation which flower during Maha (short day) season.
Understanding morphological variation of Ma wee is useful in future analysis for genetic
diversity. Thirty nine Accns of Ma wee varieties used for the present study with the objective
of determining variation of morphological responses when Accns remained in vegetative
phase under non-inductive photoperiod for flower initiation at 210 days after sowing. Thirty
nine Accns from plant genetic resources center, Sri Lanka were grown in Kamburupitiya with
four replicates in a completely randomised design at the end of Maha season in 2013/2014.

Quantitative characters of plant height (PH), total tiller number (TTN), total leaf number
(TLN), culm number (CN) and ligules length (LL) and qualitative characters of ligule color
(LC), ligule shape (LS), internode color (IC), culm strength (CS) were recorded. None of the
39 Accns flowered by 210 days and PH, TTN, TLN, CN, and LL varied from 87.5±1.61 cm,
2±0.37, 8±0.84, 2±0.43, 1.8±0.46 cm to 199±1.36 cm, 22±2.09, 136±2.20, 24±2.03 and
4.18±0.25 cm respectively. The lowest PH, TTN, TLN, and CN were recorded from Accn
6253. Except for Accn 6253, rests 38 Accns were over 1 m in PH.

Qualitative characters varied among clusters without any uniformity for a given cluster. CS
varied among Accns from weak, intermediate to strong. LC and IC varied from green to
white and green to yellow respectively. Acute to acuminate and two cleft LS were also
observed. Principal Component Analysis followed by Cluster Analysis was performed using
data from quantitative characters. First two of PCs explained over 80% of total morphological
variations. The first PC represented the PH, TTN, TLN and CN whereas PC2 represented the
LL. Eight clusters were obtained at rescaled distance five in the dendogram. Variation among
Accns within clusters for qualitative characters may be an indication of genetic diversity.

Keywords: Ma wee, Morphological variation, Vegetative phase