Format: ORAL

Allison Miller1, 2, Molly Hanlon2, Matthew Rubin2

1 Department of Biology, Saint Louis University, St. Louis, MO, USA 2 Danforth Plant Science Center, St. Louis, MO, USA

A fundamental question in plant evolutionary biology is how species that live for multiple years balance resource allocation over time to sexual reproduction (seed production) relative to vegetative growth. One component of this is understanding how reproductive output covaries with vegetative traits (e.g., stem thickness, leaf number, leaf thickness, physiology, root biomass, etc.), how these relationships shift from one year to the next, how they vary under different environmental conditions, and how they change in response to strong selection for increased reproduction output. Although the direction and magnitude of trait correlations can constrain or enhance response to artificial or natural selection, there are few comprehensive studies that describe relationships between traits expressed at early life stages (e.g., seed size and weight, germination timing, germination rate) with traits expressed later in life (e.g., reproductive output, root/shoot biomass ratio in Y1, Y2, Y3, etc.) in perennial herbaceous species. Here, we phenotyped seeds and seedlings of 1,650 plants representing eleven perennial, herbaceous species in the Asteraceae, Fabaceae, and Poaceae families, planted those individuals in a spaced plant nursery in Gray Summit, MO USA, and monitored height, flowering time, and yield over three years. We estimated root traits via soil cores in Y2 and Y3, and then excavated root crowns for further phenotyping. Analyses to date indicate strong correlations within and among life-stages, among reproductive and vegetative traits, and among above- and belowground traits. These core questions can provide key insights into how perennial, herbaceous species evolve under in nature and under artificial selection, and may expedite pre-breeding and domestication of perennial grain crops through early stage selection of traits correlated expressed in seeds and seedling that correlate with desirable traits expressed at later life stages.