Decoding the phenomenon of combining ability for yield and related traits with reference to maize

Abstract

Knowledge of combining ability of inbred lines is vital for effective exploitation of heterosis for enhancing yield in hybrid breeding programmes. Two types of combining ability analysis i.e. general combining ability (GCA) and specific combing (SCA) are reported. While general combining ability governed by additive variance reflects the average performance of parental lines in combination with several other lines, specific combining ability refers to the performance of a specific cross combination involving two parental lines and is the result of non-additive gene action. In the initial phase of breeding programmes, GCA assumes higher importance with, SCA coming into play in later stage of the hybrid development programme, once lines with high GCA are identified and designated to their respective heterotic pools. Lines with high GCA can be used to predict single cross heterosis and therefore it is imperative that heterotic pools with high GCA variance based on combining ability performances are developed. Dissecting the genetic basis of GCA with the help of molecular markers can help to further improve GCA evaluation of the lines for enhancing hybrid development programmes.