I’ve now reviewed 6 academic books regarding plant breeding .
One of them is listed in post #1. Four others are books assembled with each chapter written by a different author and listed under the name of one or two editors. These kinds of books offer summaries of individual research programs and methodology, but are not very useful for learning a subject. They are sort of – what you eat for dessert.
But here is a book used at Penn. State for horticulture undergraduates and was recommended by the professor. I think some of you might find it useful.
Principles of Plant Genetics and Breeding, By George Acquaah