Abstract:
Grain quality improvement of rice is considered as prioritized research area in rice breeding programs
in Sri Lanka. Amylose Content (AC) is a key determinant of end quality of rice. Amylose Content is
controlled by granule bound starch synthase (GBSS) enzyme which is encoded by waxy gene, located
on chromosome 6. Similarly another character associated with grain quality, Gelatinization
Temperature (GT), is controlled by the alkali degeneration locus (alk), which encodes for a soluble
enzyme called starch synthase IIa (SSIIa). Two SSR markers RM 190 and RM 314 were selected
from the previously developed QTL maps that showed association with AC and GT. This study
demonstrates the feasibility of RM 190 and RM 314 for the detection of polymorphism associated
with AC and GT. In total, 18 different rice varieties were analysed. The relationship between marker
genotype and amylose content was detected by comparing the pooled AC under 2 different allele
categories using Mann-Whitney Test. The results indicated that RM 190 was able to detect genetic
variation among the rice varieties quite efficiently, on the basis of which, the rice varieties could be
identified with two categories; with low AC and with intermediate and high AC. Therefore, the SSR
marker, RM 190, could be efficiently employed in large-scale screening programmes to predict AC
through Marker Assisted Selection (MAS).
