Plant Breeding Methods (CS, HS 541)

Semester Project


All students will write a semester project which will consist of a summary of information on breeding a particular crop. The crop chosen will be one that is of interest to the student, but that the student has not worked with before as part of a graduate or undergraduate research program. It would probably benefit the student most if he would choose a crop totally unrelated to the one he has worked with or is working with (for example: choose peaches if you are working with soybeans). Approve your choice of crop with me so that we will not have more than one person working on a crop.


You have just received your graduate degree in plant breeding and have been assigned to lead a breeding program on a crop that is new to you. Summarize the important information that you will require to begin breeding this crop using the following format:

  • A sentence outline (outline with facts, references, figures and tables) is due on lecture 20 (your copy is all I need)
  • The rough draft is due on lecture 29 (give me your copy and I will return it with comments)
  • The final report is due on lecture 38 (make sure the title page, abstract and literature cited is separate for copying)


The semester project has been assigned 1) to familiarize you with the process involved in starting a breeding program, 2) to teach you something about a crop you have not worked with before, and 3) to broaden your understanding of plant breeding methods and how they are applied to different crops.


Keep the report as short as possible. (It will usually require around 20 to 40 typed pages to cover the essential material). It is intended that you will carry out this assignment just the way you would if you had arrived at your new job. Therefore, any sources may be used to gather information for the report: extension bulletins, books, journals, class notes, U.S.D.A. production statistics, plant breeders and other researchers working with the crop of interest (both on and off campus), the reference librarian, and your classmates. Use a format similar to that used in Crop Science journal for headings, subheadings, reference citations, etc. You should start working on this project now, completing those sections that you can, and then work on the remaining sections as we cover those topics in class.


Following is an outline with examples of how you might organize your semester report.

    • Place the title, author, date and abstract on the first page.
    • Place the Literature Cited on the second (and third, fourth, etc. if necessary) page.
    • We will get every student a copy of all the semester projects through the Literature Cited section for future use.
    • Students should obtain complete copies of the papers they are interested in by contacting the student who wrote it.
    • Introduce the crop, giving its Latin binomial (Genus-species), its importance to U.S. agriculture, the main production areas, any production techniques that affect breeding methods or objectives, production statistics (area, yield, dollar value, production), and what the important characteristics of the crop are (Which would be necessary for the ideal cultivar to have considering yield, quality and stress resistance?).
    • List the full classification of the crop from Kingdom to botanical variety including any subtaxa necessary (subclass, tribe, subspecies, etc.).
    • List any related species that are agriculturally important and how they are related to your crop: Are they intercrossable? Do they differ in chromosome number? Is one a polyploid relative of the other?
    • Discuss how related species might be used in a breeding program.
    • What are the centers of origin or centers of diversity for your crop and its related species?
    • Where has germplasm been collected, and where might future germplasm explorations be made?
    • What cultigens are available to plant breeders working with this crop (cultivars, breeding lines, plant introduction lines)?
    • Is your crop asexually or sexually propagated?
    • Is it cross- or self-pollinated, or is there apomixis?
    • Is self incompatibility, male sterility, or genetic control of sex expression important in production or breeding of this crop?
    • What is the floral morphology and pollination technique for making crosses?
    • How would your pollination tags be filled out (use an example)?
      • List the important genes for the crop giving its symbol, name, description, the cultigen that contains it, and a reference for the naming author.
      • How could these genes be used in a breeding program (consider especially those genes for plant type, and insect resistance, and quality)?
      • List the heritability, variance component analysis, and genotype x environment interactions reported, in the literature for the important quantitative traits such yield, quality, and stress tolerance.
      • What is known about heterosis and inbreeding depression for the agriculturally important quantitative traits?
    • What are the important diseases, insects, and environmental stresses in the U.S. production areas for this crop?
    • What is known of the genetic resistance to these stresses?
    • Which cultivars could be used as sources of resistance? You will probably need to talk to plant pathologists, entomologists and extension specialists, as well as plant breeders for this information.
    • What potential is there for use of tissue culture, genetic engineering, mutation breeding, haploids, polyploids, or interspecific hybridization in improving your crop?
    • What methods should be used in selecting for superior cultivars? (There may be different methods for different sets of traits depending upon the inheritance you described in the genetics section above).
    • Outline a comprehensive breeding program for developing superior cultivars (using both diagrams and text). Include population improvement, inbred development, and the production of hybrids and synthetics where applicable.
    • What cooperative testing organizations are there for yield trials?
    • What groups are there for plant breeders to keep up with others working on the same crop?
    • How would you keep pedigree records for your breeding program (use an example record from a plant breeder who works with this crop if you like)?
    • What kind of data sheets could be used for the experiments and yield trials you will need to run (use examples from plant breeders here, too)?
    • What sort of planter, harvester, stress testers would you use?
    • How would you measure yield, quality, and other performance traits?
    • Speculate on the potential for improving the crop.
    • What would be the ideal set of characteristics for this crop?
    • What trend will change the breeding objectives for the crop in the future (mechanization, disease, etc.)?