Validation of dna markers linked with fertility restorer genes of wild abortive cytoplasm in rice (oryza sativa l.)

Cytoplasmic male sterility-fertility restoration (CMS/Rf) system based three line hybrid rice breeding is popular in rice production worldwide. The conventional method of restore line identification among rice germplasm pool is time consuming and labor intensive. Molecular mapping of fertility restorer genes (Rfs) for various CMS sources in rice have yielded several closely linked DNA markers that can be used in identifying restorer lines. In order to utilize this available information effectively in marker assisted restorer line identification, validation of reported Rf gene linked DNA markers was carried out in this study. A total of eleven DNA markers spread across 5 chromosomes (Chr. 1, 4, 7, 10 and 12) reported to be closely linked with five Rf genes of wild abortive CMS source (WA-cms) were chosen. These markers were screened among thirty rice genotypes involving seventeen WA-cms (A-line) and thirteen restorer lines (R-line). The genotypic data set was generated based on the specific PCR product size. The restoration ability of the rice lines used in this study was estimated by test cross procedure involving two cms lines IR58025A & IR68888A; and their F1s were studied for the percentage pollen and spikelet fertility. The marker-trait association analysis was carried out using Crop Stat and “TASSEL” (Trait Analysis by aSSociation, Evolutions and Linkage) software programs. Analysis of Variance (ANOVA) results indicated seven markers were significant. Amongst, four markers namely RM490/Rf3, RM6100/Rf4, RM311/Rf5 and RM258/Rf6 had higher phenotypic variance (R2 value) compared to the rests and therefore these marker/gene combinations can be utilized in marker assisted identification of restorer lines of WA-cms. The beneficial alleles for each of the significant markers such as 95bp &105bp alleles of RM490/Rf3, 164bp allele of RM6100/Rf4, 179bp allele of RM311-Rf5, 187bp allele of RM258-Rf6 were identified for the gain in trait.