Location: Plant, Soil and Nutrition ResearchTitle: The Genetic Architecture of Maize Flowering Time Author
|Buckler, Edward - Ed|
|Holland, Jim - Jim|
|Guill, Katherine - Kate|
|Oropeza Rosas, Marco|
|Sanchez Villeda, Hector|
Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2009
Publication Date: 8/7/2009
Citation: Buckler Iv, E.S., Holland, J.B., Mcmullen, M.D., Kresovich, S., Acharya, C., Bradbury, P., Brown, P., Browne, C.J., Eller, M.S., Ersoz, E., Flint Garcia, S.A., Garcia, A., Glaubitz, J.C., Goodman, M., Haries, C., Guill, K.E., Kroon, D., Larsson, S., Lepak, N.K., Li, H., Mitchell, S.E., Pressoir, G., Peiffer, J., Oropeza Rosas, M., Rocheford, T., Romay, C., Romero, S., Salvo, S.A., Sanchez Villeda, H., Sun, Q., Tian, F., Upadyayula, N., Ware, D., Yates, H., Yu, J., Zhang, Z. 2009. The Genetic Architecture of Maize Flowering Time. Science. 325(5941):714-718. Interpretive Summary: What is at the basis of natural phenotypic variation? Do a few or many genes control this variation? Are there multiple variants at each of these genes? These are central questions for medicine and agriculture. This study has used maize flowering time as a model to begin addressing these questions. The largest study of its kind, our research suggests that each trait in maize is controlled by fifty to 100 genes. Because flowering time is a trait whose variation allows us to grow maize in different environments throughout the world, identifying and understanding the genes behind this trait has important implications for agriculture as well as for expanding our knowledge on genetic variation for other species. This study identifies new variants which control flowering time, and we will soon be able to map the association between genes and traits for the complete set of genes in maize.
Technical Abstract: Flowering time is the key trait controlling adaptation of plants to their local environment, and, in an outcrossing species like maize, it is a complex trait. Variation for this complex trait was dissected in maize using a novel set of 5000 recombinant inbred lines (maize Nested Association Mapping population; NAM) that were specifically designed to capture much of the genetic variation in this very diverse species. In an evaluation across eight environments of nearly a million plants, we found no evidence for large effect quantitative trait loci (QTL) but rather evidence for numerous small effect QTL. Many of the QTL appear to be shared among families, with alleles having different functional effects at each QTL distributed across founder lines. Although allelic effects at many loci are loosely related to founder geographic origin, no individual QTL defines geographic population structure. The contributions of epistasis and interactions with the environment to phenotypic variation were minimal. As a result, a simple additive model accurately predicts flowering time for a range of related germplasm. By combining NAM linkage mapping with gene-phenotype association data, we were able to evaluate the effects of several genes controlling flowering. As genomic resources are developed for maize, this panel will provide tremendous opportunities to dissect complex traits and mine maize variation for improvement.