Development of multiparent advanced generation intercross (magic) populations for gene discovery in rice (Oryza sativa L.)
2010
Bandillo, N. | Muyco, P.A. | Caspillo, C. | Laza, M. | Sajise, A.G. | Singh, R.K. | Gregorio, G.B. | Redona, E. | Leung, H., International Rice Research Inst., Los Baños, Laguna (Philippines) Plant Breeding and Biotechnology Div.
Sixteen diverse accessions, eight each from indica and japonica subspecies, were used to developed two MAGIC populations for identifying quantitative trait loci (QTL) for multiple traits. These founder lines selected to maximize the number of favorable genes pooled in each population, were genotyped using 50 simple sequence repeat (SSR) markers before several cycles of intermating and are being genotyped with 1536 single nucleotide polymorphism (SNP) markers to assess genome-wide variation. These lines were phenotyped for highly-heritable traits under different non-stress and stress (drought, salinity, iron toxicity, zinc deficiency and salinity-submergence) conditions. In the first crossing cycle, 28 half-diallel crosses were made for each population. The single crosses were used to generate 70 out of 210 possible four-way crosses that were then used to develop 35 out of 105 possible eight-way crosses, with each founder line being genetically represented in each eight-way cross. At least 1000 recombinant inbred lines (RILs) will be produced by single-seed descent for each population. At least two generations of intro- and inter- population will be done to ensure rapid and uniform decay of linkage disequilibrium across the whole genome. With this MAGIC permanent mapping populations will be generated for localizing multiple QTLs to regions of 3 cM or less. The novel allele rearrangements and enhanced genetic diversity in these highly recombined MAGIC populations will facilitate the discovery of favorable genes/gene combinations. These populations can be used directly for developing varieties adapted to different rice-growing environments of Asia and Africa.
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