Plant & Animal Genomes XVI Conference Plant & Animal Genomes XVI ConferenceJanuary 12-16, 2008
Town & Country Convention Center
San Diego, CA
Yunbi Xu1 , Shibin Gao1,2 , Debra J. Skinner1 , Carlos Martinez1 , Alan F. Krivanek1 , Jonathan H. Crouch1
Marker-assisted selection (MAS) traditionally relies on leaf DNA-based genotyping, the scale and efficiency of which has been constrained by the time consuming nature of sample collection, labeling and tracking back to the source plants after genotyping. A seed DNA-based high throughput genotyping system has been developed in maize that is applicable to many other crops. The DNA extracted from sampled endosperm (30 mg) of a single maize seed is sufficient for 200-400 agarose gel-based SSR marker analyses or potentially sufficient for several million chip-based SNP marker analyses. On this basis, the seed DNA-based genotyping is suitable for all MAS applications for any crop with relatively large seeds. It is highly efficient, in terms of both time and cost, and every step can be automated except for the initial seed sampling process. There are several variables that will affect the success of transferring this method to other crops: (1) seed size, shape, texture, and moisture content affect the ease of seed sampling; (2) the amount of fat, protein and starch affect the quality and quantity of DNA recovered; (3) the nature of the sampling affects seed germination and seedling establishment; and (4) hetero-fertilization, endosperm triploidy and pericarp contamination influence the correlation between genotypes obtained from seed DNA and leaf DNA. Seed DNA-based genotyping can be used to select desirable genotypes before planting, thereby allowing improvements in molecular breeding efficiencies by optimizing the population size and structure that is subjected to subsequent phenotypic selection.