Understanding mechanisms shaping phenotypic variation over space and time is a fundamental goal in biology and the foundation of domestication and crop improvement. Perennial plants comprise an estimated 40% of domesticated species and 60% of seed plants. Their long lifespans influence evolutionary processes and patterns of variation in unique ways relative to annual systems. We study perennial crops and wild perennial species in the field, often over the course of multiple years. We generate genetic data and patterns of gene expression, and measure plant traits including flowering time, fruit and seed chemistry, leaf shape, ion concentration, and physiology, among others. Our goals are to advance basic understanding of evolution and plasticity in perennial plants, and to apply this work to perennial crop improvement, the development of novel crops for natural systems agriculture, and the conservation of perennial plant genetic resources.
One ongoing project focuses on the lesser-known half of the perennial crop equation, the root system. Grafting is the horticultural practice that unites the root system (rootstock) of one plant with the shoot system (above-ground portion of the plant) of another, and is a common practice used in more than 70 perennial crops. We are studying grafted grapevines to learn more about how different roots influence whole plant function. In grapes, the vast majority of cultivated grapevines consist of a European species (V. vinifera ssp. vinifera) that is grafted to rootstocks derived from native North American Vitis species. We are documenting patterns of genomic and morphological variation in natural populations of rootstock species and exploring root system-shoot system interactions in experimental rootstock trials.
A second research trajectory focuses on perennial herbaceous plants, which are common in nature but relatively rare in agriculture. We are working with The Land Institute and the Missouri Botanical Garden in order to build a botanical foundation for perennial polyculture agriculture. The goal of this work is to document taxonomy, morphology, ethnobotany, and toxicology of wild, perennial, herbaceous members of the grass, legume, and sunflower families in order to identify candidate species for pre-breeding and domestication. Comparative analyses of closely related annual and perennial species, as well as selection experiments are planned in order to understand the evolution of perennial herbaceous plants under selection for increased reproductive effort.
Various other research projects focus on domesticated fruit and nut trees and their wild relatives.