Preecha Prathepha

pp. 1 - 8

Abstract

Sixty-eight strains belonging to two species of Oryza were characterized by using Wx microsatellite,
(CT)_n repeats that are closely linked to the rice Waxy gene. These strains included high-, intermediate- and
low-amylose strains as well as glutinous rice. The polymerase chain reaction (PCR) was used to amplify a
DNA fragment including the beginning of exon 1 and the beginning of the intron 1 of the Waxy gene. The
amplified DNAs were sequenced an ABI Model 377 automatic sequencer.
Ten Wx microsatellite classes were identified. The popular Thai jasmine rice, KDML105, contained
the (CT)₁₇ repeats in the wx locus. Moreover, the (CT)₁₇ repeat is the predominant class of the strains tested,
whereas the (CT)₁₁ class associated with high-amylose strains. In addition, a unique microsatellite class,
(CT)₁₈, was detected in some traditional glutinous strains and glutinous wild rice collected from the northeastern region.
The restriction pattern of polymerase chain reaction-amplified Waxy DNA digested with AccI was
also characterized. Polymorphism was observed between rice strains with low amylose and intermediate
and high amylose content.