Abstract

The genetics of resistance to grey leaf spot (GLS) disease, grain yield and selected agronomic traits was studied in 42 F₁ progenies from a full diallel cross among seven maize inbred lines. These 42 F₁ progenies and seven parents were evaluated at three locations; Kenya Agricultural Research Institute (KARI), Kiboko, KARI Kakamega and University of Nairobi (Field station) during the period June 2006 to April 2008. The experiments were laid out in a randomized complete block design with three replicates. Combining ability analyses were conducted on the across site data of grey leaf spot disease, grain yield and selected agronomic traits using Griffing’s method one, model one in the SAS program. Additive gene action played a greater role than non-additive gene action in the inheritance of resistance to grey leaf spot disease whereas the non additive effects were more important in the inheritance of grain yield. Reciprocal effects were not significant for GLS disease resistance and grain yield indicating absence of maternal effects for these traits. The inbred lines, CML 384 and CML 373 were the best combiners for grain yield with general combining ability (GCA) effects of 0.79 and 0.56 respectively while TZMI 711 and CML 373 were the best combiners for GLS resistance with highest negative values for GCA of -0.51 and -0.398, respectively. The local maize breeders could now incorporate the genes for GLS resistance in CML 373 and TZMI 711 and the grain yield genes in CML 384 into elite lines using recurrent and backcross methods, respectively in order to increase maize production and productivity in Kenya.

Key words: Maize, Zea mays, grey leaf spot, grain yield, combining ability