Determination of combining abilities for grain yield and grey leaf spot resistance among selected maize inbred lines
Maize is a staple food crop for about 90% of Kenyans. Its production by smallholder farmers often plays a vital role in food security and alleviating poverty. Grey Leaf Spot (GLS) caused by Cercospora zeae maydis significantly reduces maize yields in farmers' fields. This study was carried out at three sites (KARI-Kiboko, Kabete Field Station and KARI-Kakamega) in 2006 to determine the combining abilities for yield. (j·LS resistance and other traits among seven selected maize inbred Iines CIVIL:204, CML 312. CML 373, CML 384, TZfv1I 102. TZMI 711 and TZIVII 712. Griffing's method one and model one of diallel analysis was used for data analysis using the SAS program. Significant differences were noted for most traits indicating that the good entries obtained in this work could be used as suitable testers in future breeding efforts. Different lines performed differently across the different sites; CML 373 with 3.16THa-1 and 2.83THa-1 was the highest yielder in KARI-Kiboko and KARIKakamega respectively whereas TZMI 711 with 8.43THa-1was the highest yielder in Kabete Field Station. However, CML 384 was the most stable highest yielding entry across environments implying that it had a high frequency of yield improvement genes. CML 373 and TZMI 711 had high GLS resistance. CML 373 and TZMI 711, which had high frequency of GLS resistance genes, could be used as male and female in hybrid combinations to impart GLS disease resistance in the elite maize germplasm. Non significant correlations were noted for GLS disease resistance and other diseases. The resistance genes in TZMI 711 and CML 373 should be pyramided into one good line to develop multiple disease resistant lines, for future development of open pollinated varieties and hybrids.