Pyramiding rust
Download as PPTX, PDF1 like686 views
This study aimed to enhance soybean rust resistance through marker-assisted gene pyramiding of the Rpp2, Rpp3, and Rpp4 genes. Study 1 validated the use of SSR markers linked to each gene for pyramiding. Study 2 evaluated combinations of the genes for resistance. Results showed complementary gene interactions increased resistance, though effectiveness depended on genetic background. Rpp3 conferred more dominant resistance. The study recommends further introgressing gene combinations into elite lines and evaluating durability of resistance.
Pyramiding rust
- 1. Enhancing soybean rust resistance through Rpp2, Rpp3 and Rpp4 pair wise gene pyramiding M. Maphosa, Talwana, H & Tukamuhabwa, P
- 2. Introduction •Soybean rust is an obligate fungal parasite with multiple hosts •It is a polycyclic disease with multiple re-infections •Genetic resistance is a long term solution •However, single genes have been overcome in certain areas whilst others show increasing susceptibility •To enhance single gene resistance & broaden the base for available resistance genes
- 3. Introduction •Conventional gene pyramiding is a challenge •It is not practically feasible in some cases •Marker assisted gene pyramiding may be a possible solution •Given that some of the resistance genes have markers associated with them •No attempt has be done to use identified SSR for MAS pyramiding & effect of pyramiding genes
- 4. Study 1 •Validate the use of SSR in pyramiding resistance genes Rpp2, Rpp3 and Rpp4
- 5. Study 1 Marker Linkage Group Position1 Resistance Gene Reference (cM) Sat_255 J 43.85 Rpp2 Silva et al. (2008) Satt620 J 53.71 Rpp2 Silva et al. (2008) Satt460 C2 111.87 Rpp3 Hyten et al. (2009) Sat263 C2 118.78 Rpp3 Hyten et al. (2009) Satt288 G 76.77 Rpp4 Yamanaka et al. (2008) AF162283 G 87.94 Rpp4 Yamanaka et al.(2008)
- 6. Study 1
- 7. Study 1
- 8. Study 2 •Evaluating the most effective resistance gene combination using sporulation & severity indices
- 9. Study 2 • All parents has severities higher that the pair wise combinations •In the F3 generation
- 10. Major Findings • Complementary gene interactions occurred resulting in enhanced resistance • The effectiveness of resistance is influenced by the genetic background of introgression • Independent genetic control of severity and sporulation in soybean rust • Disproportinate contribution of resistance, Rpp3 more dominant
- 11. Recommendations • MAS gene pyramiding is feasible • Introgression to elite lines • Evalution of pairwise genes in other areas • Assessing for durability of the resistance
- 12. Acknowledgements •RUFORUM •International Foundation for Science (4968-1) •Makerere University Soybean breeding programme