PartialThree-way Cross Plans for Hybrid Production

Abstract

The selection of appropriate parental lines and crossing plans are the most important keys for success in the area of hybrid production.Three-way cross breeding has been a major tool for the development of present day commercial hybrids.Three-way crosses are intermediate between two-way and four-way cross hybrids with respect to uniformity, yield, stability and the relative simplicity of selecting and testing. Three-way cross hybrids are more stable and they exhibit individual as well as population buffering mechanism because of the broad genetic base. As the number of lines increases number of crosses also increases and hence in such situation taking a sample from all possible three-way crosses, known as partial three-way cross, is always economical. Here, a method of constructing Partial Three-way Cross designs has been developed. The method is based on BIB designs. The efficiency factor pertaining to general combining ability effects of half parents as well as full parents in comparison to a Complete Three-way Cross plan, assuming constant error variance over both the cases, has been computed and is found to be very good. The method is illustrated through an example.