Wednesday, 12 September 2012

MAGIC: A new genetic resource for multiple trait improvement and QTL discovery in rice

Plant Breeding, Genetics, and Biotechnology Division Seminar

By Nonoy Bandillo
Assistant scientist
Plant Breeding, Genetics, and Biotechnology Division

1400 H, Wednesday, 19 September 2012
Room A, D.L. Umali Building, IRRI


Key economic traits in rice, such as tolerance to biotic and abiotic stresses, are quantitatively inherited and influenced by large GxE interactions. Their complex inheritance and often narrow genetic base for mining favorable alleles make trait improvement through breeding inherently difficult.

To harness natural allelic variation comprehensively in breeding while allowing the genetic dissection of complex traits individually, we generated a multi-parent advanced generation intercross (MAGIC) population using, as the founder parents, 8 elite indica and 8 japonica cultivars with desirable traits such as high yield, good grain quality, and tolerance to a suite of stresses.

We have developed 4 multi-parent populations: Indica MAGIC (8 indica parents); MAGIC Plus (8 indica parents with two additional rounds of 8-way F1 intercrossing); Japonica MAGIC (8 japonica parents); and the Global MAGIC (16 parents—8 indica and 8 japonica).

The Indica MAGIC population is the most advanced and comprises of 1,328 lines produced by using single seed descent (SSD). Genome-wide association mapping using genotyping-by-sequencing enabled us to tag known genes/QTLs, such as the Sub1 for submergence tolerance, qBR9.1 for blast disease resistance, and Saltol for salinity tolerance, with SNP markers within or very close to the gene/QTL itself. Several novel QTLs for these same traits were also identified.

The new and diverse genetic resource promises to be a valuable source of breeding-ready materials for the extraction of new commercial varieties with multiple economically important traits as well as a rich resource for fine mapping QTLs and/or combining QTLs for multiple traits in rice.

In this presentation, Nonoy will describe the development of different MAGIC populations in rice and discuss its potential application for mapping quantitative trait loci (QTLs) and rice varietal development.

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