Combining Ability in Maize Breeding Programs in Sub-Saharan Africa: A Systematic Review.

Area of Science:

• Agricultural Science
• Plant Breeding
• Genetics

Background:

• Combining ability (CA) analysis is crucial for evaluating parental genetic potential in maize hybrid development.
• Its application in overcoming maize production constraints in sub-Saharan Africa (SSA) requires further understanding.

Purpose of the Study:

• To review recent applications of CA analysis in addressing maize breeding challenges across SSA.
• To summarize findings on the role of CA in enhancing maize productivity and resilience in the region.

Main Methods:

• A systematic literature search was conducted across ScienceDirect, Springer, and Google Scholar for studies from 2020 to September 2025.
• PRISMA guidelines were followed, including 94 eligible studies focusing on maize, combining ability, and SSA.

Main Results:

• Nigeria, Ethiopia, and Ghana were key research locations, with yield improvement as the primary breeding objective.
• General combining ability (GCA) significantly contributed to hybrid performance (80%), indicating high additive gene effects, especially with inbred lines.
• The line × tester mating design was the most common approach.

Conclusions:

• Combining ability analysis is essential for enhancing maize productivity and resilience in SSA.
• It facilitates the identification of superior parents and the development of widely adapted hybrids.
• The predominance of GCA highlights the importance of additive gene action in maize breeding programs within SSA.