Wednesday, November 15, 2006

Changes in Root Morphology and Architecture Exhibited in Maize Seedlings Exposed to Varying Nitrogen Levels.

Kelvin Grant, Tim Setter, and Margaret Smith. Dept Plant Breeding & Genetics, Cornell University, G-40 Emerson Hall, Ithaca, NY 14853

Roots are the initial entry point for soil N to enter a maize plant. How seedling roots develop under varying N levels can be used by plant breeders to select parental material for studies in Nitrogen Use Efficiency (NUE) in maize. A panel of 30 diverse maize inbreds was grown in a greenhouse and fertigated with either 5.0mM NO3 (High N) solution or 0.2mM NO3 (Low N) solution. Seedlings were harvested at 10, 20, and 30 days after planting (DAP) and scored for root morphology: vertical vs. lateral growth, root architecture: branchiness and root mass. As expected, genetic differences were noted within the inbred panel at 10 DAP and 20 DAP regardless of N level. Differences were also noted among inbreds themselves at the varying N levels with more lateral growth at Low N exhibited as early as 20 DAP. Variances in branchiness were also noted as early as 20 DAP. These variegated responses to N levels could help a maize plant overcome early season low fertilization.