According to Bennett (1965), the introduction of wild plants into cultivation and the successful transfer of cultivars, with their genotypes unaltered, to new environments is called as ‘primary’ plant introduction and the rest as ‘secondary’ introduction.

Secondary sources are works that analyze, assess or interpret an historical event, era, or phenomenon, generally utilizing primary sources to do so. Secondary sources often offer a review or a critique. Secondary sources can include books, journal articles, speeches, reviews, research reports, and more.

Secondary data can be obtained from different sources:

• information collected through censuses or government departments like housing, social security, electoral statistics, tax records.
• internet searches or libraries.
• GPS, remote sensing.
• km progress reports.

Primary Introduction: For example, dwarf wheat varieties like ‘Sonora-64’, ‘Lerma rojo’ and dwarf rice varieties like ‘Taichung Native 1’, ‘IR-8’ are the examples of primary introduction.

How to Read a Book

1. Read the title. Define every word in the title; look up any unknown words.
2. Look at the table of contents. This is your “menu” for the book.
3. Read the book from the outside in. Read the foreword and introduction (if an article, read the first paragraph or two).
4. Read chapters from the outside in.

For a historical research project, secondary sources are generally scholarly books and articles. A secondary source interprets and analyzes primary sources. These sources are one or more steps removed from the event.

Secondary sources provide good overviews of a subject, so are particularly useful if you need to find about an area that’s new to you. They are also helpful because you can find keywords to describe a subject area, as well as key authors and key references that you can use to do further reading and research.

Secondary sources can be found in books, journals, or Internet resources….

1. the online catalog,
2. the appropriate article databases,
3. subject encyclopedias,
4. bibliographies,
5. and by consulting with your instructor.

The Internet is currently a component of the secondary data sources, one of the possible secondary data sources. The use of the Internet as a secondary source of data means both advantages and disadvantages; the qualities of the Internet should not be overvalued, although they exist.

Examples of Tertiary Sources: Dictionaries/encyclopedias (may also be secondary), almanacs, fact books, Wikipedia, bibliographies (may also be secondary), directories, guidebooks, manuals, handbooks, and textbooks (may be secondary), indexing and abstracting sources.

The first edition of Encyclopaedia Britannica was a secondary source when first published in 1768; but today it is a primary source to historians.

Always cite Britannica as your source when you use information from it in a report or research paper. A citation in three different formats is generated for you automatically when you view an article.

The articles in Britannica are written by authors both identifiable and credible. Many articles provide references to books and other sources about the topic covered. Undergraduates are rarely permitted to cite encyclopedia articles.

In addition to the full text database and thousands of illustrations, Britannica Online served as a gateway to the World Wide Web by providing direct links to outside sources of information.

Database management system. Connolly and Begg define database management system (DBMS) as a “software system that enables users to define, create, maintain and control access to the database”. Examples of DBMS’s include MySQL, PostgreSQL, Microsoft SQL Server, Oracle Database, and Microsoft Access.

Databases support good data access because: Large volumes of data can be stored in one place. Multiple users can read and modify the data at the same time. Databases are searchable and sortable, so the data you need can be found quick and easily.

Database, also called electronic database, any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval, modification, and deletion of data in conjunction with various data-processing operations.