Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Getting Closer To The Salt Tolerance Gene

Ellen T. Tumimbang¹ , Dante L. Adorada¹ , Johnathan Niones³ , Fazle Elahi² , Zeba I. Seraj² , Jan Dvorjak⁴ , Glenn B. Gregorio¹

¹  Plant Breeding, Genetics and Biochemistry Division, IRRI, DAPO Box 7777 Metro Manila, Philippines

²  Dhaka University, Dhaka, Bangladesh

³  Philippine Rice Research Institute, Munoz, Nueva Ecija, Philippines

⁴  University of California Davis, California, USA

The analysis of quantitative trait loci (QTLs) associated with salinity tolerance was carried out using a population of near-isogenic lines (NILs) BC3F4 derived from Pokkali as donor and IR29 as recurrent parent (IR29/Pokkali//3*IR29). The near isogenic lines were developed to fine map the major QTL for salinity tolerance in chromosome 1 of rice. Twenty-six plants composed of three families were selected to generate 10,000 BC3F4 plants to fine map the salinity tolerance gene in chromosome 1. Seven microsatellites (RM8115,RM140, RM493, RM8094, RM3412, AP3206 and Ap3722) and three EST markers (CP6224, CP010136 and CP03970) were used to saturate the region where the major QTL for salt tolerance was mapped. Linkage and graphical genotype analyses were done and each marker and tolerance score were subjected to QTL detection based on single marker analysis and correlation test. Two new markers, CP6224 and RM8094 flanking the previously mapped major Saltol QTL at 5.75 cM interval distance were found significantly associated with the salinity tolerance trait. Genotyping of other families of the near-isogenic line population is on-gong to further reduced the distance of the flanking markers associated with salt tolerance gene. Markers highly associated with the trait will be used for marker-assisted breeding in developing salinity tolerant varieties.