Abstract

                                A study to determine gene action, heritability and number of effective genes controlling 13 traits utilizing Jinks - Hayman diallel analysis of the populations raised by a fix6 diallel cross of fourth generation inbred lines of cassava showed that overdominance governed most of the traits including yield and yield components. The number of gene groups controlling various traits was estimated and root yield was found to be controlled by 3 gene groups. Very low narrow sense heritability obtained for yield and its components also revealed the preponderance of non-additive gene action. The (Vr. Wr graph confirmed the role of overdominance for yield and its major components. The standardised deviation graph was used to identify superior parents. The study indicated the possibility of genetic improvement in cassas a through heterosis breeding.

Key words : Cassava, diallel, overdominance, yield components