UC Davis

Plant breeding is the art and science of developing new crops and plant products that serve an immense range of industries. The scientific training for plant breeders often involves making discoveries in plant genetics to develop new tools for plant breeders. The first part of this Thesis describes the discovery, validation, and deployment of WHEAT ORTHOLOG OF APO1 (WAPO1), a gene that increases the spikelet number per spike (SNS) and yield potential in wheat. The path from discovery to deployment of WAPO1 was a three-step, forward genetics approach that first involved construction of a high‑resolution genetic map, followed by candidate gene evaluation and functional validation experiments to demonstrate that WAPO-A1, the A genome homeolog of WAPO1, is a causal gene for SNS. With causality established, an extensive germplasm screen was performed to discover and characterize novel alleles for WAPO-A1. To raise durum yield potential, a WAPO-A1 allele associated with higher SNS was deployed into durum wheat and raised SNS significantly. If this increase in SNS translates into higher yield, plant breeders could make targeted introgressions of WAPO-A1 alleles into widely grown durum varieties to improve durum yield. Beyond scientific training and crop-specific knowledge, plant breeders also need to be competent in a wide variety of technical and soft skills. The second part of this Thesis is an assessment of students’ learning and skill development in the Student Collaborative Organic Plant-breeding Education (SCOPE) program: a student-led collective that uses technical training, social learning, and mentorship to prepare students for a career in plant breeding. Two educational theories – Experiential Learning and Situated Learning – served as the conceptual basis for this study’s design, implementation, and interpretation of results. To determine how well students were acquiring new technical and soft skills, I conducted a mixed methods study of anonymous surveys and analysis of student writing pieces from the SCOPE program. This study found that most students participated in all plant breeding activities and were building new knowledge and skills accordingly. SCOPE staff were the primary mentors to all students, while graduate students played dual roles as mentors to undergraduate students and mentees to staff and faculty advisors. However, undergraduate students rarely achieved proficiency in advanced skills, and few mastered more basic skills despite frequent practice and training. I suspect the unclear leadership role of undergraduate participants in the SCOPE community hampered learning and skills acquisition. If given a clear role and more responsibility, students would likely gain confidence in their training and take greater initiative and responsibility for their own learning. To make these suggestions a reality, this study concludes with recommendations for feasible undergraduate-led projects that would hopefully improve undergraduate skills development and benefit the SCOPE community.