Development of submergence tolerant hybrid rice through marker assisted backcrossing
2012
Esguerra, M.Q. | Dela Paz, M.A.G. | Lales, J.H. | Larazo, W.M. | Paragas, E.L. | Qui, F. | Xie, F., International Rice Research Inst., DAPO Box 7777, Metro Manila (Philippines). Plant Breeding, Genetics and Biochemistry Div.
Hybrid Rice is known to increase rice yield up to 15 to 20% where as Sub-1 gene gives rice the capability to withstand submergence for a number of days. Developing hybrid rice with submergence tolerance will increase rice production and reduce losses in areas frequently devastated by flooding. The aim of this experiment is to upgrade elite hybrid parents through incorporation of the Sub-1 gene and ultimately produce rice hybrids with tolerance to submergence. The use of marker-assisted backcrossing (MAB) technology was employed to ensure gene transfer after submergence screening. Hybrid parents used in the breeding were IR68897 B and SRT3R, while PSBRc68 served as the Sub-1 donor. F1'cs obtained from hybrid parent and donor parent crosses were backcrossed with recurrent parents. BC1F1 progenies were then subjected to submergence screening in which IR42 and PSBRc68 served as susceptible and tolerant checks, respectively. Water was removed as soon as the IR42 showed complete mortality. Surviving plants were grown further with DNA samples collected for confirming Sub-1 gene presence. Plants with Sub-1 gene were backcrossed twice to produce BC3F1S that will be subjected once again to submergence and marker screening as well as backcrossing to produce BC4F1. Background selection through single nucleotide polymorphism (SNP) genotyping will be performed on BC4F1S to guarantee that 'upgraded' hybrid parental are of high genetic similarity with the original recurrent parents. In addition, the lines maintaining and restoring characters will be verified through testcrosses. Phenotypic selection will be carried out for parent lines with desirable characters, and increased as parents for hybrids with submergence tolerance.
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