Incorporation of submergence tolerance, controlled by Sub-1 locus, into local rice varieties was attempted by using DNA marker assisted breeding. Submergence tolerance among tested rice varieties was accurately phenotyped by evaluating acclimative shoot response. Submergence intolerant varieties displayed greater shoot elongation while submergence tolerant plants showed restricted elongation during submergence. During de-submergence all susceptible varieties withered and perished while tolerant plants showed nearly 100% survival and they were assigned the survival score of 1. Microsatellite DNA markers RM 464A and RM 219 that are linked to Sub-1 were used to genetically screen for Sub-1 locus. Two alleles (226 and 231 bp) of RM 464A marker were detected among the tested varieties. All the tested varieties displayed 226 bp allele of RM 464A with the exception of variety Bw 363 (231 bp). Higher allelic variability (190, 214, 220 and 230 bp) for RM 219 marker was observed. The polymorphism detected for RM 464A and RM 219 between varieties IRRI 119 (Sub-1 donor) and Bw 363 has allowed us to identify specific alleles of the two markers. The haplotype of 226 bp allele of RM 464A and 220 bp allele of RM 219 were used as diagnostic alleles or gel bands to monitor Sub-1 in IRRI 119 × Bw 363 cross. Easily-scorable bands for these two markers accurately and reliably distinguished submergence tolerant plants in a F 2 population. These results demonstrated that the two studied DNA markers can be used to introgress Sub-1 locus into local rice varieties to achieve submergence tolerance.
Rathnayake, N., Bentota, A., Dissanayake, D., Perera, K., Sooriyapathirana, S., & Jayasekera, G. (2013). DNA Markers RM 464A and RM 219 Haplotypes are Effective in Selecting Sub-1 locus for the Introgression of Submergence Tolerance into New Rice Varieties. Ceylon Journal of Science (Biological Sciences), 41(2), 125. https://doi.org/10.4038/cjsbs.v41i2.5382