Germplasm Development of Underutilized Temperate U.S. Tree Crops

Abstract

In the Midwest U.S. dominated corn-soybean landscape, agroforestry systems can be particularly valuable for increasing the provisioning and regulatory capacity of the agricultural landscape. However, these systems have not yet been broadly integrated into the landscape of this region since they are mostly relegated to marginal lands. A growing body of literature suggests a path to increase the adoption of agroforestry in the Midwest U.S. lies in the incorporation of low-input food-producing tree species that provide economic incentives for farmers. Studies of the system-level integration of such approaches have proceeded by using the currently available cultivars and breeding selections of various tree nut and fruit species. While existing varieties and breeding selections provide the opportunity for initial system development and integration, their broad adaptability to the Midwest U.S. and its marginal land-types is unexplored. Thus, a second tier of research includes the genetic improvement and adaptation of tree crop selections to their respective target environments throughout the Midwest U.S. Fortunately, select tree crops of interest are amendable to systematic breeding and have wild relatives that are endemic across the region. In this paper, we discuss the value of these wild relatives for broadening the adaption of cultivated tree crop selections by using the hazelnut as an example species. We present a framework using geospatial tools to define and prioritize target environments for breeding and, in turn, exploiting wild relative germplasm.

Using Living Germplasm Collections to Characterize, Improve, and Conserve Woody Perennials

“…are one of many tree crops that can be integrated into agroforestry models. Current breeding efforts are making use of American and European hazelnut germplasm collections in accelerating the introgression of commercially important traits such as climatic tolerance, disease resistance, and improved nut quality to expand the viability of this crop (Revord et al, 2019). Thus, living germplasm collections represent a crucial source of diversity used by breeders to improve perennial crops.…”

“…Recent work by Hoban et al (Hoban and Schlarbaum, 2014;Hoban et al, 2018) improves on previous recommendations for gathering diverse collections for ex situ conservation, demonstrating that simulations using species-specific information such as population structure can be used to optimize collection efforts and greatly reduce the number of collections required to conserve allelic diversity. In particular, in order to capture genetic diversity, extensive sampling of wild relatives across a broad geographic range is essential because species may be locally adapted to different environmental conditions and diseases (Revord et al, 2019).…”

Morphological Traits and Chemical Composition of Hazelnut from Different Geographical Origins: A Review

“…To the best of our knowledge, reviews on hazelnut physio-chemical properties are limited. Moreover, the Turkish hazelnut supply and production have strongly fluctuated in recent years, due to abiotic stresses in the plantations, causing peak prices and market instability [38]. Furthermore, Chile, China, and Azerbaijan all increasing their rank in the current international market, due to the exploitation of seasonality in contrast with European trades.…”

Characterization of black walnut (Juglans nigra) cultivars for agroforestry systems

“…Despite the potential of ACS in the Midwest, adoption has remained low. While farmers are interested in using agroforestry on their land (Mattia et al, 2018), scaling the adoption of ACS with specialty nut crops, such as Chinese chestnut (Castanea mollissma Blume) , hybrid hazelnut (Corylus avellana L. X C. americana Marshall) or eastern black walnut, will depend on the development of improved cultivars through breeding and selection Mori et al, 2017;Revord et al, 2019). A challenge to designing agroforestry systems is identifying compatible tree species and cultivars/breeding selections with desirable commercial traits and reduced interspecific competition with alley crops (Desclaux et al, 2016;Santi & Ferrandez, 2014).…”