C-RUI: Tolerance to Damage: Examining Genetic Architecture and Selection of Candidate Traits Using Hybrid Willows

Vassar College, Poughkeepsie NY

Investigators

Abstract

0108172 Fritz It is well know that some plant species tolerate damage by herbivores more than others, but information about how natural selection acts to change the expression of tolerance is scarce. In this project, the investigators use a hybrid willow system to examine the role of tolerance to damage as an adaptive response to browsing herbivores. The researchers will evaluate traits that confer tolerance to damage, measure the selection gradient for those traits in F2 hybrids, determine the sets of trait combinations that are generally favored by selection, use six genetic classes of willows to investigate the genetic architecture of tolerance and its traits, and determine how plant age alters tolerance and its mechanisms. To evaluate these aspects of tolerance to damage, plant cuttings propagated from controlled crosses will be grown in common gardens, given a treatment of either 50% shoot damage or 0% shoot damage, and evaluated for fitness responses and for traits that confer fitness. By measuring the selection gradient for candidate traits of tolerance, the researchers will elucidate the role that natural selection can play in the evolution of tolerance to damage. In addition, they will assess how past selection has shaped the expression of tolerance traits in each parental species. By determining how tolerance to damage is expressed, they can evaluate the influence of epistasis on the evolution of tolerance, as well as the presence or absence of additive genetic variance between the two plant species. These findings will provide insight into the potential for hybridization to enhance the adaptive responses of plants to herbivore damage.