Rapid Screening Methods for Identification of Resistant Maize Inbreds to Fungal Foliar Pathogens

Background and Objective: Maize (Zea mays L.) is an important cereal that provides nutrition for about 50% of the global population. Despite the numerous benefits and potential of the crop, maize is susceptible to various biotic stresses that limit its maximum yield potential. Host plant resistance (HPR) has been adjudged the best option among the various options for disease management. However, identifying sources of resistance among maize genotypes maximizes the efficiency of HPR. The present study compared the effectiveness of the rapid laboratory assay; the detached leaf assay (DLA) with screen house screening for rapid identification of disease-resistant maize genotypes. Materials and Methods: Ten each of the early and extra-early maturing maize inbreds were screened for resistance to Bipolaris maydis (SLB 02) and Exserohilum turcicum (NGIB16-13), respectively. The screen house experiment was laid in a restricted randomized complete block design with two replications and disease severity was measured using a 1-9 scale weekly after inoculation. Four-weeks-old leaves of each genotype were inoculated with 40 µL of 10^-5 spores/mL of the pathogens using the DLA, in a completely randomized design. Data collected were subjected to ANOVA and significant means were separated using Fisher’s LSD at 0.05 probability level. Results: The DLA and screen house experiments were compared and were found to be similar. The TZEEI 179, TZEEI 8 and TZEEI 20 were identified as SCLB-resistant inbreds while TZEI 56, TZEI 60, TZEI 86 and TZEI 128 were found to be NCLB-resistant genotypes using both methods. Conclusion: The DLA is an efficient technique for identifying disease-resistant early and extra-early maturing genotypes and could facilitate the rapid development of disease-resistant maize hybrids and open-pollinated varieties. Adopting the disease-resistant genotypes would reduce crop losses, increase farmer’s income and ensure food security.