Marker-assisted backcrossing (MABC) for improved salinity tolerance in rice (Oryza sativa L.) to cope with climate change in Vietnam

Abstract

Abstract Salinity is the most common abiotic stresses leading to the reduction of rice yield in many rice-growing areas of the world. Improvement in salt tolerance of rice for target stress regions is one of the important objectives of many breeding programs. In this study, we are currently applying a MABC (marker-assisted backcrossing) system on foreground selection, recombinant selection followed by background selection for development of Vietnamese rice variety that can tolerate salinity of rised sea water. The highly salt tolerant FL478 was used as a donor to transfer Saltol QTL into Bacthom 7 recipient rice cultivar. A total of 368 SSR markers were conducted to identify 8 markers in Saltol locus and 81 markers in other loci with total of 89 (24%) polymophic markers between the parents, out of which 88 markers were then applied to analyze genotyping of each backross generation with three steps of selection. The results showed that, the best plants of BC3F1 generation carry segments of the donor (11.16 -12.6 Mb), which had 96.8% -100 % of the recipient genome. This study revealed that the introgression lines can be directly developed into the salinity tolerance variety, which suitable for cultivating in coastal areas of Vietnamese Deltas. The MABC aids in the transfer of target chromosome segments and may improve the recovery of the recipient genome if background selection is employed