The heritability of gene expression is critical in understanding heterosis and is dependent on allele-specific regulation by local and remote factors in the genome. In this study, we used RNA-Seq to test whether variation in gene expression among F1 and F2 intraspecific Salix purpurea progeny is attributable to cis– and trans-regulatory divergence using two distinct tissue types: shoot tip and stem internode. In addition, we explored sexually dimorphic patterns of gene expression inheritance and regulatory divergence among F1 individuals.
Altogether, our results offer insight into the inheritance of gene expression in S. purpurea as well as evidence of sexually dimorphic expression which may have contributed to the evolution of dioecy in Salix.
Each year, the New York State Agricultural Experiment Station in Geneva, NY hosts undergraduates from across the country for an eight week Summer Research Scholar program that seeks to engage students in research projects focused around one of four areas: entomology, food science, horticulture, and plant pathology.We are excited to take this opportunity to highlight our 2017 Summer Research Scholars, Jennifer Myers and Jubilee Park.
Jenny is a student at the University of Nebraska – Lincoln, majoring in plant biology. After graduating, she is planning to attend graduate school in horticultural plant breeding and research. This summer, Jenny is conducting research on the genetic basis of sex determination in shrub willow.
Jubilee is a student at Emory University in Atlanta, Georgia, majoring in environment science. She plans to pursue a graduate degree in a plant science related field after spending a year teaching English in South Korea. Her work this summer is focused around characterizing pest resistance in a varied population of shrub willow.
Yield improvement of woody bioenergy crops has been the major focus of breeding programs, but biomass quality is also important for conversion to biofuels. Using high-resolution thermogravimetric analysis, the composition of biomass samples from two shrub willow (Salix spp.) yield trial networks representing two distinct datasets were examined. Dataset 1 consisted of 12 yield trials containing 10 genotypes that mainly represented early cultivars from the US breeding program. Dataset 2 consisted of five trial locations containing 19 genotypes from later breeding efforts. The genetic variation in wood composition as well as the ability to modify composition via management, indicate that both new genetic resources and management can be used to optimize biofuel conversion efficiency.
“The use of mixed models has allowed us to analyze a large yet unbalanced dataset of shrub willow yields in order to characterize GEI. The main findings are incremental increases in yield were achieved through traditional breeding techniques, that interspecific triploid hybrids seem to express the largest yield gains, especially in warmer environments, and that the GEI allows for the identification of cultivars adapted to low and high-yielding environments. This is critical for deploying regionally adapted and high-yielding genotypes for stands expected to be productive over 20 years. As a result of this work we have identified a number of recently bred, high-yielding triploid hybrids from diverse pedigrees that will be advanced for commercialization.”
Root biomass is an important trait often disregarded in woody perennial selection due to the challenge and expense of accurately and efficiently measuring large populations. In this study, we aim to develop a simple method that can predict root dry weight within a diverse shrub willow (Salix spp.) breeding population representing species hybrids and their parents using root electrical capacitance (REC). This work provides an efficient and nondestructive technique to indirectly quantify root biomass of genetically diverse shrub willow progeny, which has great promise for selection of genotypes with varying root biomass and for the accurate estimation of belowground carbon sequestration.
Shrub willow is showing promise as a dedicated bioenergy crop in areas of North America. Early breeding efforts have demonstrated that its broad taxonomic diversity can be exploited for genetic improvement. However, a comprehensive evaluation of the yield potentials of currently available cultivars has not occurred in North America. We used the Additive Main effects and Multiplicative Interactions (AMMI) model to explore genotype by environment interactions for the identification of broad and specific adaptation. We confirmed ploidy level as a key genetic factor involved in yield improvements which will be important for developing cultivar recommendations and informing future breeding work.
“…Larry Smart and his team will explore the genetic basis for rust resistance in shrub willow. By using cutting-edge genetic mapping approaches to identify the genes involved in rust resistance in willow, the team can generate molecular markers to be used by breeding programs in the early selection of resistant seedlings.”
“The focus of the project is to ensure the long-term sustainability of the crop, maintaining yields and continuing to breed improved cultivars.”
Matt Hayes is managing editor and social media officer for the College of Agriculture and Life Sciences.
The Cornell Chronicle is Cornell’s primary source of news since 1969. The site publishes daily news about research, outreach, events and the Cornell community.
New Willowpedia fact sheets published in August 2015 describing the latest shrub willow cultivars commercialized for bioenergy in Larry Smart’s breeding program are now available on the Willowpedia website.
‘Fabius’ has been tested across a wide range of sites and is a consistent winner relative to other cultivars according to recent research by Ph.D. candidate Eric Fabio in Smart’s lab. It produced over 6 dry tons per acre per year in a trial in Middlebury, VT and has produced similar yields in trials in Geneva, NY.
‘Preble’ has been tested on a fewer number of sites, but it has also yielded over 6 dry tons per acre per year on Northeast sites. A US Plant Patent was issued for ‘Preble’ on June 10, 2014.
Both of these cultivars are in Diversity Group 8, which also includes ‘Tully Champion’, ‘Otisco’, and ‘Owasco’. It is strongly recommended that fields should be planted with cultivars from different diversity groups either in blocks or in random mixtures to slow the onset of disease and pest outbreaks and to capitalize on the ability of genetically diverse cultivars to excel in various microsites across a field.
The willow cultivar genetic diversity groups were recently revised by Smart’s lab when it became known that ‘SX61’ and its offspring, ‘Canastota’, ‘Marcy’, and ‘Sherburne’, should be classified as Salix miyabeana and placed in Diversity group 5.
This fact sheet also includes a table of relative susceptibilities of the current commercial cultivars to common pests and diseases. The fact sheets were authored by Ph.D. candidate Fred Gouker and Larry Smart and were partially supported by Agriculture and Food Research Initiative grant 2012-68005-19703 for the NEWBio Project from the USDA National Institute of Food and Agriculture.