PBG Content Committee

PBG Style Guide

This Style Guide provides detailed information on the style and formatting conventions used in authoring articles for the Plant Breeding and Genetics Community of Practice on eXtension, but it is not exhaustive. For additonal information on style and formatting, refer to (in order of preference) the eXtension Manual of Style, the Wikipedia Manual of Style, the Chicago Manual of Style, and the Merriam-Webster Unabridged Dictionary. For a general overview on authoring PBG articles for eXtension, see the PBG Instructions for Authors.

  1. Introduction to Web Styling
  2. Article Titles
  3. Section Headings
  4. Capitalization
  5. Acronymns and Abbreviations
  6. Italics
  7. Spaces
  8. Quotations
  9. Punctuation
  10. Scientific Style
  11. Pronouns
  12. Language and Spelling Variations
  13. Bulleted and Numbered Lists
  14. Tables
  15. Figures
  16. References

Introduction to Web Styling

The Edit form translates text into HTML code. Do not cut and paste text directly into the Edit form from a word processing document, as this introduces additional formatting. Instead paste into the Edit form using the “Paste as Plain Text” function. Hyperlinks and formatting will need to be added after pasting as plain text. Give all images an alternate text description in the imagine property box to assist the visually impaired.

Other web styling issues to consider are usability and actionability. Usability involves ease of reading and scanning. Make sure that headings, subheadings, and titles are clear and descriptive. Keep sentence and paragraph structure as simple as possible, and use graphics, bullets, and charts where appropriate. Actionability involves linking articles to related materials and guiding users to further information. Articles should connect users to additional sources of information.

Article Titles

Keep article titles short—no more than 5 or 6 words, if possible. Compose titles using language appropriate for a general, rather than a specialist, audience. Compose titles and headings as nouns or noun phrases. Do not begin titles and headings with A, An, or The as the first word unless, by convention, it is an inseparable part of a name.

Use the key words that a reader looking for your content would use in a search engine.

Capitalize all major words; do not capitalize articles, coordinating conjunctions, and prepositions unless they are the first or last word. In hyphenated compounds, capitalize second and subsequent major-word elements.

Section Headings

Guidelines for article titles apply to section and subsection headings as well.

Avoid repeating or referring to article titles or higher-level headings in section and subsection headings.

Use Heading 2 format for section headings, and Heading 3 format for subsection headings. Use subsections sparingly.

Do not use hyperlinks in headings.

Do not insert blank lines before or after headings.


Refer to the Merriam-Webster Unabridged Dictionary for specific words.

Capitalize all proper nouns, including the names of months, days, and holidays; the names of planets and stars; the names of ethnic, socioeconomic, and other groups; directions and regions, and their related forms, when parts of formal or informal names (North Carolina; Southern California; Southerner); titles of people when used as part of the title (President Obama), but not when used generically (Barack Obama is an American president); scientific names of subgenera and higher taxa of plants, animals, and other organisms (but not the species name in latin binomials); and the names of institutions.

For the common names of species, capitalize only proper nouns and adjectives. When in doubt, do not capitalize.

Do not use all capital letters for emphasis (except in a direct quotations); use bold type instead.

Use all capitals for acronyms and initialisms.

Acronymns and Abbreviations

Do not assume that readers know the meanings of acronymns and abbreviations; write out the words in full on first occurrence, followed by the acryonym or abbreviation in parentheses. An exception is made for abbreviations that are as well-known or better known than their full name, such as PhD and DNA, for which is it unnecessary to supply the full name on first occurrence.

In general, the letters of acronymns (words formed from the initial parts of a name, such as NATO) and initialisms (a group of initial letters, each pronounced separately, used as an abbreviation for a name or expression, such as PBS or BBC) are not separated by periods or spaces; notable exceptions include U.S. (the abbreviation for United States), and certain latin abbreviations.

Latin abbreviations—ca., cf., et al., e.g., i.e., etc., N.B., and  P.S., for example—should be used in parenthetical material only; in regular text, spell out the English equivalent. Refer to the Merriam-Webster Unabridged Dictionary for the proper punctuation and capitalization of latin abbreviations.


In the body of articles, italicize the latin genus or genus-species names of organisms; the names of genes; and the titles of books, computer software, films, works of visual art, and periodicals (newspapers, journals, and magazines).

Use italics when introducing or distinguishing among terms.

Use italics for phrases in other languages and for isolated foreign words that are not in common use in English (i.e., they do not appear in the the Merriam-Webster Unabridged Dictionary).


Use only a single space—not double spaces—after all punctuation (including periods, question marks, exclamation marks, and full colons), with the exception of the colon separating a volume or serial number from page numbers in a list of references (use a single non-breaking space after the colon).

Use a non-breaking space (Shft-space) to prevent line wrapping from presenting elements that would be awkward at the beginning of a new line. For example, use a non-breaking space between values and abbreviations for units of measure.


Identify in the text the author of a quote of a full sentence or more, unless clearly unnecessary.

Distinguish long quotations (more than four lines of text, or more than one paragraph) from other text using blockquote formatting (the blockquote key in the editor menu).


Quotation Marks

Use only straight (typewriter) double quotation marks. Do not use single quotation marks for quotations-within-quotations; search engines consider single quotation marks to be parts of words or phrases.

Do not use “scare quotes”.

Do not use quotation marks with block quotes.

In the body of articles, use quotation marks around the titles of articles, essays, papers, and chapters of a longer work.

Punctuation with Parentheses, Brackets, and Quotation Marks

A sentence wholly within parentheses or brackets has it's punctuation inside the parentheses or brackets; a sentence ending in parenthesized or bracketed text has its punctuation outside the parentheses or brackets.

Place punctuation inside quotation marks if they are part of the quotation, and outside if they are not.

Serial Comma

Use a serial comma immediately before a conjunction in a series of three or more items.

  • Incorrect: Solanaceous vegetables include tomatoes, potatoes and peppers.
  • Correct: Solanaceous vegetables include tomatoes, potatoes, and peppers.

If any element of a series contains a comma, use semicolons to separate the elements of the series.

When a series of items is numbered, enclose the numbers in parentheses.

Hyphens (-)

Hyphens indicate conjuction.

Hyphenation involves many subtleties, especially for compounding; refer to the Chicago Manual of Style for comprehensive rules.

Derivatives—words containing a prefix, suffix, or combining form—are almost always written as one word (e.g., pretreatment, clockwise, fourfold [but 4-fold]). The following prefixes always require a hyphen: all-, ever-, ex-, great-, half-, much-, self-, still-. Otherwise, hyphenate prefixes only with homographs to prevent confusion about meaning (e.g., co-op vs. coop); with proper nouns, capitalized abreviations, and numbers (e.g., pre-Darwinian; anti-WTO; pre-1960s); with combinations that bring awkward combinations of words together (e.g., semi-independent); or with hyphenated adjectives (e.g., semi-winter-hardy). If in doubt, check the Dictionary.

Use a hyphen between the spelled-out numerator and denominator of a fraction (e.g., two-thirds), except where one is already hyphenated (e.g., thirty-two hundredths).

Use hyphens to join numbers and prefixes in chemical names (e.g., 2-deoxyribose).

Hyphenate a compound adjective before, but not after, the word modified (e.g., winter-hardy plant; but the plant is winter hardy).

Hyphenate compound adjectives that include a number (e.g., 500-mL flask; 3-yr-old plant).

Do not use a hyphen after a standard -ly adverb (e.g., newly germinated seed).

Use a hanging hyphen in serial compound adjectives having a common base (e.g., two- and three-digit numbers; north- or eastward leaning).

En Dashes (–)

Use an en dash to indicate a minus sign (e.g., –40°C).

Use an en dash to indicate a range (e.g., June–September). If a number in the range is negative or otherwise modified, use the word to instead of a hyphen (e.g., –4 to 20°C)

Use an en dash in a compound or prefixed adjective that has a phrase in one of its parts and the phrase cannot be hyphenated (e.g., Solanum lycopersicon–derived resistance genes).

Use an en dash between joined nouns of equal importance (e.g., marker–trait association; Waller–Duncan k-ratio).

Use a spaced endash in lists to separate distinct information within points (e.g. Step 1 – DNA extraction)

Em Dashes (—)

Em dashes indicate interruption in a sentence.

Use an em dash to indicate an abrupt break in thought—more so than is given by a colon or a semicolon.

Use em dashes parenthetically, giving more emphasis than commas, but less emphasis than parentheses.

Use em dashes sparingly, and without spaces.

Scientific Style

Use the International System of Units (SI) in text that is mathematical, statistical, technical, or scientific. Make exceptions to this guideline if there are compelling historical or pragmatic reasons to do so (for example, Hubble's constant should be quoted in its most common unit of (km/s)/Mpc rather than its SI unit of Hz). For nontechnical writing, use either Imperial or metric units.

In text about chemicals and chemistry, use the style of the International Union of Pure and Applied Chemistry (IUPAC) for chemical names wherever possible, except in article titles, where the common name should be used if different, followed by mention of the IUPAC name.

In periodic table groups, use the new IUPAC names (these use Hindu-Arabic numerals, not Roman numerals or letters).

Pronouns - Traditional Science Research Writing Style

When it comes to the use of pronouns, there are 2 options, depending upon the target audience for the material being written: the traditional science research style and the contemporary science education style. Choose whichever style is most appropriate for the particular case, but be sure to stay consistent within a piece of text material—do not switch back and forth between the two styles within the same body of content. 

The traditional science research writing style is best used when communicating research findings and procedures to a formal, academic research audience.  This particular style guide section is written in a traditional science research style, in contrast to the next section which is written in the contemporary science education style.  In the traditional style, the speaker (writer) is communicating more formally, at a distance from the audience and not engaging the reader in a 2-way conversation or with any interactivity with the content.

To utilize the traditional style, except in quotations, avoid the use of first- and second-person pronouns—such as I, you, and wewhenever possible.

Pronouns - Contemporary Science Education Writing Style

The second writing style you may use is what we are calling contemporary science education writing style.  This particular style is more useful when communicating a science concept for your target audiences such as students, agricultural industry clientele, and teachers. This section of the style guide is written in this contemporary style. You will likely notice the contrast between the two readily.

In the contemporary style, the speaker (writer) is communicating less formally. It is when you wish to engage your learners into more of a 2-way conversation.  You may ask questions within the text, which requires them to stop, think and apply the new concept you have outlined for them. Even though you are not communicating with them synchronously, you are encouraging them to have a dialogue with your written text which requires them to be a more active learner, rather than a possible tendancy to just pasively reading text without stopping to think through the applications.

There is educational research findings which indicate this type of writing is more effective in helping the learner grasp new, difficult concepts.

So what are some ways to help you write in the more contemporary style? I like to picture in my mind 2 scenerios.  In the first, I picture a typical scientific conference presentation, where the speaker is on a podium at the front, flipping through powerpoints to explain to an audience of 100+ researchers the significance of her/his latest experimental findings. This would represent a traditional science research writing style. 

In the second, I picture in my mind the typical lab setting for my genetics class where I am sitting at a round table, with 5 of my students.  They are stuck on one of the assignment questions and need further explanation.  I am not simply giving them answers, but providing further questions to help direct them down their own path of discovery and understanding. Sometimes I am drawing pictures, sometimes referring to other diagrams, but always it is a 2-way conversation. In this manner my students receive instant feedback as to whether or not they are mastering the concepts.

This contemporary style, then, tries to recreate the face-to-face live setting in an online, asynchronous format. It readily uses pronouns such as I, you, and wewhenever possible and incorporates questions to help the reader reflect and apply her/his new knowledge. If the electronic software allows, features such as the following are include to foster interactivity: video clips, pop up quiz questions with explanations, animations, storytelling - where real case examples are used to illustrate a science concept, etc.

Again, for the Plant Breeding and Genomics Community of Practice, we have decided that you, as the content writer, are free to choose whichever style you feel best meets the needs of your target audience. We just ask that you stay consistent with the style's use of pronouns within the piece of material you write.

Language and Spelling Variations

The Merriam-Webster Unabridged Dictionary is the dictionary of choice for spelling and related items.

Bulleted and Numbered Lists

Do not use lists if the text reads easily using plain paragraphs.

Use the same grammatical form for all elements in a list, and do not mix the use of sentences and sentence fragments as elements.

When the elements of a list are complete sentences, format them using sentence case and a final period.

When the elements of a list are sentence fragments, introduce the list with a lead fragment ending with a colon. Format the elements in sentence case, except for titles of works, which retain the original capitalization of the title. End each element with a semicolon, or with a period for the last element. Alternatively (especially when the elements are short), use no final punctuation at all.

Use numbers rather than bullets for the elements of a list only if a need to refer to the elements by number may arise; the sequence of the items is critical; or the numbering has some independent meaning, as in a listing of book chapters.


Do not use tables if the information is more appropriately or economically presented in graphs or in the text using plain paragraphs.


Reduce images to the display size (maximum 500 pixels, 72 dpi) before uploading them and inserting them into content; oversized images can consume significant bandwidth and can slow down webpage access for those who are restricted to dial-up connections.

Number figures consecutively. When a figure is comprised of two or more parts, identify the parts with lowercase letters. In the article text, refer to figures using the abbreviated form (e.g., Fig. 1).

Provide a descriptive caption below each image, beginning with a figure number in unabbreviated form and ending with an image credit as follows:

Figure 1. This is an example of a figure caption. (a) Description of first photograph. (b) Description of second photograph. Photo credits: (a) Name1, Affiliation1; (b) Name2, Affiliation2.


Follow the conventions outlined in the ASA–CSSA–SSSA Publications Handbook and Style Manual (ASA–CSA–SSSA, 2004) for compiling and formatting bibliographic information for resources listed in the References Cited, External Links, and Additional Resources sections of articles, with the exception that (1) full journal titles will be used, not abbreviations, and (2) URLs for internet versions of print resources will be included, if available (HTML in preference to other formats). 

For background, here are Modern Language Association's thoughts on citing web publications:

Checklist of General Principles

  • Make sure that bibliographic information has been compiled properly.
  • Cite the references in the text using "(Author last name, year)" such as: (Zaborski, 2008; Zitherly, 2002a, b, 2004).
  • Make sure that all references cited in the text appear in References section, and vice-versa.
  • Verify that hyperlinks in references are correct.
  • When multiple versions of online resources are available, preferentially link to HTML versions.
  • Use an en-dash to convey the sense of to or through, particularly in ranges (such as ranges of page numbers and dates of Proceedings).
  • Use only single spaces, not double spaces.
  • Names (punctuated initials and surname) in a series of authors or editors are separted by commas; the last name in the series is preceeded by a comma and the word 'and'; two initials are separated by a single space, but three or more initials are not separated by spaces.
  • Only the first author in a list of authors or editors at the beginning of a reference is listed surname first, a comma, and initials; list remaining names initials followed by surname.
  • Capitalize the first word of title and subtitles of articles, bulletins, or books, as well as capitalizing proper names.
  • Do not use abbreviations for titles of journals, books, proceedings, and so forth; capitalize all major words in journal, series, or Proceedings titles.
  • Though it is generally desirable to refer to primary sources, this may not always be desirable with linked media content (e.g. videos housed on YouTube). You may refer the user to an intermediate source if the intermediate source may be more robust, if there would be potential benefit to directing users to the intermediate source, or if there may be undesirable content associated with your content (e.g. "directly related" videos on YouTube may not be appropriate).

Articles in Periodical Publications

Elements of a reference to an article in a periodical publication, in order, are: author(s), year of publication, full title of article, title of publication, volume and inclusive page numbers.

  • Journal Article
    • Scott, J. W., J. B. Jones, G. C. Somodi, and R. E. Stall. 1995. Screening tomato accessions for resistance to Xanthomonas campestris pv. vesicatoria, race T3. HortScience 30: 579–581.
  • Article in Serial Publication
    • Egley, G. H. 1986. Stimulation of weed seed germination in soil. Reviews of Weed Science 2: 67–89.
    • Weller, D. M., J. M. Raaijmakers, B. B. M. Gardener, and L. S. Thomashow. 2002. Microbial populations responsible for specific soil suppressiveness to plant pathogens. Annual Review of Phytopathology 40: 309–348. (Available online at: http://dx.doi.org/10.1146/annurev.phyto.40.030402.110010) (verified 17 March 2010).
  • Magazine Article

Chapters or Articles in a Larger Work (Book, Proceedings, etc.)

Elements of a reference to a chapter or article in a larger work (such as a book or proceedings), in order: author(s), year of publication, full title of chapter or article, inclusive pages, the italicized word 'In', the name(s) of any editors followed by '(ed.)', the full publication title, volume and edition number (if applicable), publisher, and city of publication. Articles in conference proceedings also require: after the proceedings title, the place of the meeting followed by a period; then the date of the proceedings.

  • Chapter in a Book
    • Liebman, M., and E. R. Gallandt. 1997. Many little hammers: Ecological approaches for management of crop-weed interactions. p. 291–343. In L. E. Jackson (ed.) Ecology in agriculture. Academic Press, San Diego, CA.
    • Norris, R. F. 1999. Ecological implications of using thresholds for weed management. p. 31–58. In D. D. Buhler (ed.) Expanding the context of weed management. Food Products Press, New York.
  • Chapter in a Proceedings Volume
    • Mazzola, M., and M. F. Cohen. 2005. Consideration of plant-microbe interactions in the application of organic amendments for soilborne disease control. p. 53–54. In D. Granatstein and A. Azarenko (ed.) Proceedings 3rd National Organic Tree Fruit Research Symposium, Chelan, Washington. 6–8 June 2005. Washington State University Tree Fruit Research and Extension Center, Wenatchee, WA.

Larger Works

  • Conference, Symposium, or Workshop Proceedings and Transactions
    • Granatstein, D. and A. Azarenko (ed.). 2005. Proceedings 3rd National Organic Tree Fruit Research Symposium, Chelan, Washington. 6–8 June 2005.   Washington State University Tree Fruit Research and Extension Center, Wenatchee, WA.
  • Books (including bulletins, reports, multivolume works, series)
    • Jackson, L. E. (ed.) 1997. Ecology in agriculture. Academic Press, San Diego, CA.
    • Liebman, M., C. L. Mohler, and C. P. Staver. 2001. Ecological management of agricultural weeds. Cambridge University Press, New York.
  • Dissertations
    • Harbuck, K. Z. 2007. Weed seedbank dynamics and composition of Northern Great Plains cropping systems. MS Thesis. Montana State University, Bozeman, MT.
    • Gaur, A., 1997. Inoculum production technology development of vesicular-arbuscular mycorrhizae. Ph. D. thesis. Univ. of Delhi, Dehli, India.

Non-Print Media

  • Both print and electronic versions available (note: link to html version is preferred over other formats (eg. PDF, DOC); for journal articles, use DOI link when available, otherwise use link to abstract page, if available, because this will be the only page accessible to those without a subscription)
    • Miller, S. A., R. C. Rowe, and R. M. Riedel. 1996. Bacterial spot, speck, and canker of tomatoes. FactSheet HYG-3120-96. The Ohio State University Extension. (Available online at: http://ohioline.osu.edu/hyg-fact/3000/3120.html) (verified 22 June 2010).
    • Jones, J. B., G. H. Lacy, H. Bouzar, R. E. Stall, and N. W. Schaad. 2004. Reclassification of the xanthomonads associated with bacterial spot disease of tomato and pepper. Systematic and Applied Microbiology 27: 755–762. (Available online at: http://dx.doi.org/10.1078/0723202042369884) (verified 21 June 2010).
  • Electronic and Other Media Sources (non-print version only)
    • Baenziger, P. S., and P. Hain. Advanced backcross breeding [Online lesson]. Plant and Soil Sciences eLibrary, University of Nebraska – Lincoln. Available at: http://plantandsoil.unl.edu/croptechnology2005/pages/index.jsp?what=topicsD&topicOrder=1&informationModuleId=959723462 (verified 22 June 2010).
    • Grubinger, V. 2004. Farmers and their innovative cover cropping techniques [VHS tape/DVD]. University of Vermont Extension, Burlington, VT.
    • Sullivan, P. 2003. Principles of sustainable weed management for croplands [Online]. ATTRA Publication #PO39. National Sustainable Agriculture Information Service. Available at: http://www.attra.org/attra-pub/weed.html (verified 21 Nov 2008).
    • Wikipedia contributors. 2010. Marker assisted selection. Wikipedia, The Free Encyclopedia. Available at: http://en.wikipedia.org/w/index.php?title=Marker_assisted_selection&oldid=396502815 (verified 19 Nov 2010).
      Note: because Wikipedia articles are subject to revision at any time, use the URL of the specific version of the page that you reference in your article. To find this URL, go to the Wikipedia page you want to cite, click on Cite this page under Toolbox in the menu on the left side of the page, and adapt the CBE/CSE style citation to the format shown above.
  • Website
    • [Author/compiler/editor etc. of the webpage, if available. Title of the page [Online]. Title of the overall website, if distinct from the page being cited. Publisher or sponsor of the site (often the copyright holder). Available at: full URL of the webpage (verified day month year).]
    • National Center for Biotechnology Information [Online]. U.S. National Library of Medicine, National Institutes of Health. Available at: http://www.ncbi.nlm.nih.gov/ (verified 22 June 2010).
    • MetaCyc Encyclopedia of Metabolic Pathways [Online]. SRI International. Available at http://metacyc.org/ (verified 22 June 2010).
    • eXtension [Online]. eXtension Foundation. Available at: http://www.extension.org/ (verified 22 June 2010).