GBS data and morphological nut trait data from two populations of hazelnut (<em>Corylus</em> spp.)

The native, perennial shrub American hazelnut (Corylus americana) is cultivated in the Midwestern U.S. for its significant ecological benefits, as well as its high-value nut crop.&nbsp;Developing improved varieties for the Upper Midwest requires validated quantitative genetic approaches to utilizing genomic data in both American hazelnut and interspecific hybrids typical of breeding programs.&nbsp; In addition, high-throughput phenotyping methods are essential to the efficient and accurate screening of large breeding populations.&nbsp; This study reports novel advances in both of these domains.&nbsp; Two populations of hazelnuts, one composed of C. americana and one composed of C. americana x C. avellana hybrids, were phenotyped over the course of two years in two locations using a digital imagery-based method for quantifying morphological nut and kernel traits.&nbsp; This data was utilized to perform both composite interval mapping (CIM), using a recently released genetic map, and geno..., Phenotyping Morphological characteristics of in-shell hazelnuts and shelled kernels were used as the trait data for this study.&nbsp; This was collected primarily using an adapted version of the digital imagery acquisition and analysis pipeline reported by (Hameed et al. 2018).&nbsp; In brief, bushes were completely harvested by hand in August 2020 and August 2021. Harvested clusters were dried in the greenhouse, husked, and 30 in-shell nuts were then randomly sampled per bush.&nbsp; These nuts were arranged on a 6x5 grid with a QR code, and a Nikon 5600 DSLR camera tethered to a desktop computer was used to acquire a single image.&nbsp; The OpenCV Python library was used to isolate each in-shell nut and produce a binary mask by applying a fixed HSV threshold to each pixel.&nbsp; An ellipse was then fit to each binary mask, and the length of its major and minor axes was calculated by converting pixel length to physical distance using a scale bar embedded in each image.&nbsp; Circularity..., , # GBS data and morphological nut trait data from two populations of hazelnut (*Corylus* spp.) ## 1. Study description Developing improved hazelnut varieties for the Upper Midwest requires validated quantitative genetic approaches to utilizing genomic data in both American hazelnut (*Corylus americana*) and interspecific hybrids typical of breeding programs. High-throughput phenotyping methods are also essential for efficient and accurate screening of large breeding populations. This study reports advances in both domains. Two populations of hazelnuts—one composed of *C. americana* and one composed of *C. americana × C. avellana* hybrids—were phenotyped over two years at two locations using a digital imagery–based method for quantifying morphological nut and kernel traits. These data were used to perform: * Composite interval mapping (CIM), using a recently released genetic map. * Genomic prediction, using a newly available chromosome-scale reference genome for *C. americana*. Multi...,