Rice salinity genes caught in action!
1999
Gregorio, G.B. | Khush, G.S. | Senadhira, D. | Ning Huang | Nandi, S. | Barrion, A.A. | Carpena, A.L. | De Ramos, M.B. (International Rice Research Inst., Los Banos, Laguna (Philippines))
Tagging genes for salinity tolerance is important in developing the PCR-based molecular marker. The genetic basis of salinity tolerance of the indica cross IR66946 (IR29-salt susceptible improved variety x Pokkali-tolerant traditional tall variety) was determined through PCR-based AFLP. The F8 recombinant inbred lines (RILs) of IR 66946 were used to map the genes for salinity tolerance in Pokkali. Phenotyping was done at seedling stage using salinized (EC= 12 dS/m) culture solution under controlled condition in IRRI phytotron. Combining the AFLP technique with selective genotyping, a linkage map for rice was established. Each linkage group was assigned to corresponding chromosome. The AFLP map consisting of 206 AFLP markers was generated from 32 primer combinations of Pst1 and Mse 1 using the 80 RILs which were selected from the extreme tails of the population in response to salinity tolerance. With the constructed AFLP map, a major gene for salinity tolerance designated Saltol was mapped between flanking AFLP markers P3/M9-8 and P1/M9-3 on chromosome 1 were the candidate SalT gene was also identified. QTL associated with salinity tolerance were tagged on chromosomes 1, 3, 4, 10, and 12. High K absorption had 3QTL, low Na absorption had 4 and low Na-K ratio absorption had 3. A common QTL for the 3 quantitative traits for salinity tolerance was observed in chromosome 1. This segment contained the saltol gene and explained a range of 64.3-80.2 percent of the phenotypic variation with LOD14.5. This study also demonstrated that the combination of rapid generation of AFLP map and selective genotyping made QTL detection fast, easy and cost effective
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