Natural Variation for Flowering Time, Perennialism, and Nutrient Recycling in Bioenergy Crops

We have analyzed annual Brachypodium for flowering time and nitrogen content when grown under a nitrogen gradient. Flowering time is correlated to whole plant N content, likely due to greater leaf mass in later flowering accessions. We hope the easily transformable annuals can assist in gene characterizations of loci identified in perennial species.  We have analyzed nitrogen content in perennial Brachypodium species to identify accessions that differ in nitrogen content following senescence. We are focusing on perennial Brachypodium species where simple genetic analysis is possible and the accessions are candidates for sequencing by JGI.  To identify loci involved in flowering/senescence/nutrient recycling in dedicated bioenergy crops, we have analyzed nitrogen content in switchgrass and Miscanthus from locations that vary in soil type. Our goal is to understand how the timing of developmental processes influence nutrient recycling in bioenergy crops.  We have extended our switchgrass studies to include Big Bluestem, and the following experiments are currently in progress to gauge the extent of nitrogen recycling in dedicated perennial bioenergy crops.

A) We have assayed several native stands, from multiple locations, to gauge the extent of genetic variability for nitrogen recycling.

B) We have planted multiple genotyped at horticultural and marginal sites to gauge genetic and environmental variation for nitrogen recycling.

C) We will grow select genotypes in a chamber under a yearly-simulated cycle to relate nitrogen recycling and below ground growth. Also, the selected genotypes will be grown on a nitrogen gradient to directly address the genetic variation in a controlled environment.