Response of some early maturing maize genotypes to southern corn leaf blight (Bipolaris maydis)

Subject Areas : Plant Pests

Samaneh Hosseinkhani ¹ , Vahid Rahjoo ² , Majid Zamani ³

1 - Former MSc. Student, Department of Plant Pathology, College of Agriculture, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran.
2 - Assistant Professor, Seed and Plant Improvement Institute, Karaj, Iran
3 - Assistant Professor, Seed and Plant Improvement Institute, Karaj, Iran

Received: 2014-06-19 Accepted : 2014-11-19 Published : 2014-11-22

Keywords: Maize, Resistance, Bipolaris maydis, lines and hybrids, bazooka technique,

Abstract :

Southern corn leaf blight caused by Bipolaris  maydis is one of the most important diseases of maize and causes major losses in quality and quantity of yield in corn. The most effective way for control of disease is use of resistant cultivars. To evaluate the reaction of maize genotypes to the disease on experiment was arranged as split plot in RCBD with three replications and 15 genotypes (6 hybrids, 9 lines and a susceptible check) at Karaj and Sari stations. The mixture of five aggressive isolates were used for artificial inoculation at two growth stages of plant (spraying with spore suspension at 4-6 leaf stage and Bazooka technique with sorghum kernels infected to B. maydis at 6-8 leaf stage). Genotypes were evaluated based on disease severity percentage on leaves two weeks after flowering time. The results of combined variance analysis showed that there was a significant difference at 1% probability level among corn genotypes. Based on the results, three lines K1263/17, K615/1, S61 and two hybrids KSC 201 and KSC 301were susceptible, four lines K1263/1, KE75039, K1264/5-1, K1728/8 and hybrid KSC 260 were moderately susceptible, two lines OH43/1-43, KE72012/12 and two hybrids KSC 250 and KSC 340 were moderately resistant. Hybrid KSC 400 was the only genotype that induced chlorotic lesion on lower leaves of all genotypes and was assessed as resistant. Due to favorable climatic conditions and high disease incidence in Sari station percentage of susceptible genotypes in Sari (53.33%) was higher than that Karaj (26.69%).