Evaluation of maize (Zea mays) inbred lines for grey leaf spot (Cercospora Zeae- maydis) resistance under artificial inoculation in Kenya

Abstract

 Grey leaf spot, caused by Cercospora Zeae maydis is the most important foliar disease of maize (Zea mays) in Sub Saharan Africa. In Kenya, small scale farmers accounts for 75% of the total maize production. However, production is constrained by grey leaf spot (GLS) among other factors, therefore, productivity can be enhanced by planting resistant varieties. The objective of this study was to screen inbred CIMMYT maize lines for source of grey leaf spot resistance. Forty-two maize inbred lines were evaluated under field conditions at KALRO Kakamega (longitude, 34° 45' 8.24" E and latitudes, 0° 17' 3.19" N) and Egerton university (longitude, 35° 55' 58.0" E, and latitudes, 0° 22' 11.0" S). The experiment was layout in a 7 x 6 alpha lattice design with two replications. Artificial inoculation techniques by prepared spores of 2.5 milligram and placed at the plant mid-rib at V6 crop stage. Data were collected using the CIMMYT maize breeder’s procedure and statistical analyses were done using the general linear model (GLM) to partition variance using SAS version 9.3 and means separated using Least Significant difference test at 5% level of significance. Disease severity based on plot severity scores was rated on a 1–9 scale at 21, 35 and 49 days after inoculation. Significant (P? .001) effects due to genotypes were observed for disease severity. Effects due to genotype by environment interaction (GEI) were significant for disease reaction. Among the screened lines, ten (CML 566, CML 539, CKDHL 120773, CKDHL 05017, CML 204, CKL15704, CML550, CML 568, CKLMARS 10677 and CML 202) were identified to be resistance. However, (POOL A6-3-1-1) was the least resistant genotype. Genotypes CML 539 and CKL O5017 exhibited disease resistance in both environments and had high grain yields. These genotypes are suitable candidates for utilization in both grain yield and GLS resistance in Kenya, thus recommended for inclusion in hybrid breeding programs.