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With climate change, the pressure on tree breeding to provide varieties with improved resilience to biotic and abiotic stress is increasing. As such, pest resistance is of high priority but has been neglected in most tree breeding programs, given the complexity of phenotyping for these traits and delays to assess mature trees. In addition, the existing genetic variation of resistance and its relationship with productivity should be better understood for their consideration in multitrait breeding. In this study, we evaluated the prospects for genetic improvement of the levels of acetophenone aglycones (AAs) in white spruce needles, which have been shown to be tightly linked to resistance to spruce budworm. Furthermore, we estimated the accuracy of genomic selection (GS) for these traits, allowing selection at a very early stage to accelerate breeding. A total of 1,516 progeny trees established on five sites and belonging to 136 full‐sib families from a mature breeding population in New Brunswick were measured for height growth and genotyped for 4,148 high‐quality SNPs belonging to as many genes along the white spruce genome. In addition, 598 trees were assessed for levels of AAs piceol and pungenol in needles, and 578 for wood stiffness. GS models were developed with the phenotyped trees and then applied to predict the trait values of unphenotyped trees. AAs were under moderate‐to‐high genetic control (h2: 0.43–0.57) with null or marginally negative genetic correlations with other traits. The prediction accuracy of GS models (GBLUP) for AAs was high (PAAC: 0.63–0.67) and comparable or slightly higher than pedigree‐based (ABLUP) or BayesCπ models. We show that AA traits can be improved and that GS speeds up the selection of improved trees for insect resistance and for growth and wood quality traits. Various selection strategies were tested to optimize multitrait gains.

Polycross-pollinated white spruce (Picea glauca [Moench] Voss) families were evaluated in field and retrospective nursery tests in 1989, 1991, and 1992, respectively. Height growth was measured at age 10 for the field tests and at ages 1 to 6 for the retrospective nursery tests. Except for a few cases, the family mean correlations between nursery and field heights were significant for the 1989 and 1992 series, and their corresponding genetic correlations ranged from low to medium (from 0.37 to 0.74). Because of heavy noncrop competition, height growth in the 1991 nursery series showed consistently lower heritabilities and correlations with field performance compared with those of the other two series. Early nursery selection by theoretical prediction was generally efficient for the 1989 and 1992 series. Rank classification analysis indicated that application of early nursery selection should be used with caution for identifying elite families but could be used to cull inferior families or clones, apply multiple-stage selection, or perform positive assortative mating.

Density Functional Theory (DFT) calculations are used to investigate electrical deactivation after heat treatment in Tellurium (Te) doped Gallium Arsenide (GaAs) semiconductors, an effect that has been observed experimentally. DFT’s predictive capabilities are explored in the generation of the Gibbs free energy surfaces of the Zirconium-Hydride (Zr-H) system. In addition to providing insights into the Zr-H phase diagram, the temperature dependence of the free energies of the various phases are important inputs into mesoscale models of Zr-based clad.GaAs is a III-V direct band gap semiconductor that, when doped with Te, becomes n-type. Previously a decrease in electrical activation has been observed in the semiconductor after annealing. In this work, charged defect formation energies have been calculated using DFT. Additionally, the energy correction term compensating for the electrostatic interactions between the defects and their periodic images has been studied and a systematic approach to similar studies is recommended. The formation of Ga vacancies with charge –3, Te substitution with As atoms with charge +1 and combinations of the two defects are found to be the most energetically favorable. This work shows that the formation of the Ga vacancy and Te-substitutional defect complexes are the most likely cause for electrical deactivation in Te-doped GaAs.Zr-alloys for nuclear fuel cladding are known to precipitate hydride phases during operation. These precipitates can cause several issues including increased stresses due to lattice mismatches between the precipitate and the alloy and hydrogen embrittlement leading to cracking and failure of the cladding. In order to predict the materials properties of the cladding, the hydride phases must be accurately simulated. The thermodynamic stability of phases in the Zr-H system was evaluated using DFT. Cluster expansion techniques were employed to assess the stability of each phase over a range of concentrations at zero temperature. Phonon contributions were calculated and combined with results of statistical mechanical techniques calculating finite-temperature energetics to create free energy surfaces for the ground states as a function of temperature and concentration. These free energy surfaces can be employed by mesoscale modeling techniques to more accurately calculate microstructure and material properties of the cladding.