Summary

This project will produce the DH and RIL acceptor line for the cold tolerance breeding program and to phenotype these lines for cold tolerance. A range of marker approaches (microsatellite mapping, QTL screening using DArT, genomics approaches) will be used to identify molecular markers that are closely linked to cold tolerance QTLs. These tools will serve as basis for future cold tolerance breeding in Australia.

Program

Rice

Research Organisation

The University of Sydney

Objective Summary

1. Production of doubled haploid (DH) populations and recombinant inbred lines (RIL) from the crosses of ‘Reiziq’ with several sources of cold tolerant varieties for cold tolerance breeding and molecular marker development. 2. Phenotyping of DH and RIL populations for cold tolerance. 3. Improvement of microspore culture system for the production of DH lines for breeding. 4. Construction of a microarray containing previously identified genes that are differentially expressed between cold-sensitive (Doongara) and cold-tolerant rice (R31 R32) and use this array to screen DH lines or RILs. This array will enable us to identify eQTLs that co-segregate with the tolerance phenotype. 5. Mapping of the cold-tolerance QTLs of R31 and R32 using populations of RIL and/or DH lines derived from the crosses between Doongara and R31 R32. R31 has so far proven to be recalcitrant to microspore culture while R32 have shown good regeneration to DH plants. For Doongara X R31 RIL lines will be used for mapping by using micro-satellite markers and microarray-based eQTL mapping. The eQTL method will enable us to precisely map the region of interest on the genome sequence which is important for subsequent fine-mapping and identification of candidate cold-tolerance genes. 6. Potential R31 and R32 cold tolerance markers will be verified in the other cold tolerant lines. 7. DH RIL populations and molecular markers for cold tolerance will be provided to the rice breeders in Yanco. 8. Establishment of microspore culture based DH production system for rice breeding.