Indian Phytopath. 65 (2) : 200-202 (2012) Turcicum leaf blight (TLB) caused by Exserohilum turcicum (Pass.) is one of the major foliar diseases of maize throughout the world causing significant grain yield losses (1 and 9). It is severe at mid-altitude in tropical regions where high humidity, low temperature, and cloudy weather prevails during the maize growing season. The disease is endemic in the states of Bihar, Karnataka, Maharashtra and Andhra Pradesh where grain yield is reduced drastically because of this disease (4 and 5). The disease also appeared regularly in the mid hills of Meghalaya in the Kharif season. In endemic areas, it is difficult to manage the disease. The disease can be minimized by foliar application of fungicides such as Mancozeb and Propiconazole and by altering the date of sowing. However, the most appropriate and economical strategy to manage this disease is through exploitation of host resistance, which is not only environment friendly but also convenient to be adopted at farmers’ level. There were several attempts made to identify the suitable maize inbreds, which could be exploited for developing resistant cultivars against turcicum leaf blight of maize. Accordingly, several polygenic resistances have been developed and reported in Indian germplasm (8). Earlier, efforts were made to identify additional sources of resistance in maize for Exserohilum turcicum (6), but breeders still lack information on the new sources of resistance. Moreover, maize being the second most important cereal crop after rice in Meghalaya and disease management is purely dependent upon resistant sources, an attempt was made to identify sources of resistance to TLB suitable for mid hill conditions of Meghalaya. Barapani, Meghalaya (India) is a hot spot for Turcicum leaf blight, where during cropping season a sizeable amount of disease is observed every year. The experiment was conducted to identify new sources of resistance among the tested genotypes. The seed of genotypes were received from Directorate of Maize Research, New Delhi. A total of 64 genotypes including hybrids, composites and synthetics were evaluated at the ICAR Research Complex for NEH Region, Barapani experimental farm, during 2007-08 and 2008-09. Evaluations were done under field conditions through the use of high performance inoculation technique for creating infection by E. turcicum. The experiment was laid following randomized complete block design with three replications. Each genotype was planted in three rows of 4 meters length with spacing of 25 cm plant to plant and 75 cm row to row. Spreader rows of highly susceptible variety RCM 1-2 were planted after every 5 th row, which served as a source of secondary inoculum for disease development. Inbred line CM 202 (established susceptible check) was planted at initial and at the last row of each replication. The inoculum was prepared using standard method (2). The plants were inoculated at 3-4 leaf stage applying two pinches (about 100 mg) of powder obtained from actual lesion area. The powder containing 0.65 x 10 4 conidia/g was applied in central whorls and then sprinkled with water. Finally the whorls were covered with polythene to create humidity. There was frequent rainfall during the crop season and relative humidity was above 80%. The disease first manifested itself by 8-12 days after inoculation depending upon different genotypes. Disease appeared quickly in infector rows and became severe by the time of silking. Disease intensity was recorded using 1-5 rating scale (7). A slight modification in the scale was made by using zero, which indicated no disease symptoms. The disease intensity was recorded on individual plant basis at silk- drying stage. Analysis of variance was performed for each year data and F-test was used for testing homogeneity of variances (3). The genotypes showing disease score between 0.1-2.0 were considered as resistant (R), 2.1-2.5 as moderately resistant (MR), 2.6-3.0 as moderately susceptible (MS), 3.1-4.0 as susceptible (S) and 4.1-5.0 as highly susceptible (HS). It was observed that the mean disease score (2.72) for 2007-08 was comparatively more (2.62) than that of 2008- 09, which may be due to environmental effect. F-test indicated the presence of heterogeneity of variance in two years data, therefore pooled analysis was not performed and two years data are presented separately (Table 1). Susceptible checks RCM 1-2 and CM 202 showed 4.50 and 4.76 during 2007-08; 4.53 and 4.71 during 2008-09, respectively, which indicated the sufficient disease pressure. Category of 23 resistant and five moderately resistant genotypes did not change during two years trial. However, may be due to slightly high disease pressure (mean disease score = 2.72) in 2007-08, four susceptible genotypes viz. BH-4069, Comp. R. 2005 - 6, DMR Synthetic-4 and JH- 31041 became moderately susceptible in 2008-09, may be Sources of resistance to turcicum leaf blight (Exserohilum turcicum) of maize for NEH region RAM DUTTA*, NGASHEPAM ANITA, SATISH CHANDRA and S.V. NGACHAN Division of Plant Pathology, ICAR Complex for NEH Region, Umiam 793 103 Key words: Exserohilum turcicum, mid-hill conditions, resistance, turcicum leaf blight SHORT COMMUNICATION *Corresponding author: rdutta.iari@gmail.com