Abstract

A study was carried out using diallel crosses in maize to determine the general and specific combining abilities in the mode of inheritance of tolerance to Striga lutea. Ten inbred parents of varying tolerance to S. lutea were crossed in half diallel to generate 45 F₁ hybrids. The hybrids were evaluated in three striga endemic locations of Southwestern Nigeria under artificial infestation in 1998 growing seasons.  The results showed that general combining ability effects were significant for almost all traits under infested and uninfested conditions. Progeny performance showed that hybrids were 86 and 40% better than their parent inbreds for striga tolerance rating and maize grain yield under artificial infestation. General combining ability (gca) effects for striga syndrome ratings were generally low with negative gca effects of -080. -0.40, -0.21,-0.15 and -0.26 in parents Tzi 97, Tzli100, Tzpi43-22, Tzmi105 and Tzpi260, respectively. Parents inbreds Tzpi97, Tzmi104, Tzpi57 and Tzli10 are good sources of gene for higher grain yield. Specific combining ability (sca) effects were also generally low for striga syndrome rating with values of -0.94, -0.77, -1.14 and 0.83 showing good tolerance. These tolerant inbreds may be adopted for commercial hybrid maize production for S. lutea endemic areas of south western Nigeria.

Key words: Striga lutea, tolerance levels, combining ability, grain yield.