Combining Ability define by Gene Action
Authors: Vivek Sharma and Ashwani Kumar
PhD Scholar Plant Breeding and Genetics


• Combining ability is a very important concept in plant breeding and it can be used to compare and investigate how two inbred lines can be combined together to produce a productive hybrid or to breed new inbred lines.


• Selection and development of parental lines or inbred with strong combining ability is one of the most important breeding objectives.

• In maize breeding, Sprague and Tatum (1942)
• Two categories of combining ability,
General combining ability (GCA)
Special combining ability (SCA).

• The GCA for an inbred line or a cultivar can be evaluated by the average performance of yield or other economic traits in a set of hybrid combinations.

• The SCA for a cross combination can be evaluated by the deviation in its performance from the value expected from the GCA of its two parental lines.

• The total variation among crosses can be partitioned into two components ascribable to GCA and SCA.







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About Author / Additional Info:
PhD Scholar Plant Breeding and Genetics
Rajasthan Agriculture Research Institute, Jaipur