Maize (Zea mays L) is the most important staple food crop in Kenya. Despite its importance, maize production is limited due to a number of factors, among them diseases and insect pests. Highland leaf blight caused by Exerohilium turcicum (Pass.) Leonard & Suggs is one of the most economically important diseases of maize in Kenya. Various maize genotypes were screened for genetic variability for resistance to E. turcicum in the greenhouse and the field. Plants were inoculated at the 6-7 leaf stage. Greenhouse test plants were incubated for 24 hrs at 100% relative humidity. Disease severity ratings were recorded two weeks after inoculation on a 0 to 5 scale in the field, and in the greenhouse the lesion lengths and widths were measured. The ratings were significantly different among genotypes and some entries were segregating into groups of resistant, intermediate and susceptible. Mean lesion length ranged from 2.73 cm for POPL 32 to 8.97 cm for M30 while width varied from 0.25 cm for PR98A to 0.57 cm for M30. Mean ratings in the field ranged from 0.5 for three entries to 3.0 for Embu 12X CN211. The resistant and/or segregating genotypes appeared adapted and have potential in Embu and other areas with a similar environment. The resistant genotypes identified need to be evaluated against blight and other major diseases under controlled or different environmental conditions at diverse locations. Identification of resistant genotypes is useful in a maize breeding programme where blight is of concern for general varietal improvement.

English

0410|AGRIS 0401|AL-Maize Program

Juan Carlos Mendieta

CIMMYT Publications Collection