RD 15 rice variety is photoperiod sensitive, tall and non-glutinous with Hd1Hd1Sd1WxWx genotypes. Improved RD 6 rice line is non-photoperiod sensitive , shot and glutinous with hd1hd1sd1sd1wxwx genotypes. This was selected in Maejo University as derived from Taichung 65 which is non-functional non-photoperiod sensitive, Hd1, gene and semi-dwarf, sd1, gene from RD 1 rice. Three markers were used: hd1 marker specific for Hd1/hd1 gene; sd1 marker specific for Sd1/sd1 gene; and wx marker specific for Wx/wx gene.