ITHACA, N.Y. Scientists have identified the genes related to leaf angle in corn (maize) a key trait for planting crops closer together, which has led to an eight-fold increase in yield since the early 1900s. (Nature Genetics, Jan. 9, 2011.)
The study, led by researchers from Cornell and the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) at Cornell and North Carolina State University, is the first to relate genetic variation across the entire maize genome to traits in a genomewide association study. The researchers have so far located 1.6 million sites on the maize genome where one individual may vary from another, and they used those sites to identify the genes related to changes in leaf angle that have allowed greater crop density.
Yield increases have mostly resulted from adaptations made by breeders to maize so crops can be planted closer together. Along with changes in roots and nutrient uptake that also play roles in increased crop densities, the leaves of maize crop plants have become more upright to maintain access to sunlight in crowded plots.
The team of researchers found that natural mutations in genes that affect ligules the first thick part of the leaf where it wraps around the stalk contributed to more upright leaves. Also, the changes in leaf angle result from many small genetic effects added together; while leaf angles may vary from one maize variety to another by up to 80 degrees, the biggest effect from a single gene was only 1.5 degrees.
"Although each gene and variant has a small effect, we can make very accurate predictions," said Ed Buckler, the paper's senior author, a USDA-ARS research geneticist in Cornell's Institute for Genomic Diversity and a Cornell adjunct associate professor of plant breeding and genetics. Lead authors include Feng Tian, a postdoctoral researcher in Buckler's lab, and Peter Bradbury, a computational biologist with the USDA-ARS in Ithaca.
|Contact: Blaine Friedlander|