RESUMEN
In the original publication [...].
RESUMEN
Northern corn leaf blight (NCLB) of maize, caused by Exserohilum turcicum (Pass.) Leonard and Suggs., is an important foliar disease common across maize-producing areas of the world, including Bihar, India. In this study, virulence and distribution of races were observed against Ht-resistant genes and also identified the E. turcicum race population distribution in Bihar. For that, 45 E. turcicum isolates were collected from maize fields in Bhagalpur, Begusarai, Khagaria, Katihar and Samastipur districts between 2020 and 2022. These isolates were screened on maize differential lines containing Ht1, Ht2, Ht3 and HtN1 resistance genes. Five different physiological races were observed based on the symptoms response of the differential maize lines. These races are race 0, race 1, race 3, race 23N and race 123N. E. turcicum race 3 was the most prevalent race having 26.6% frequency followed by race 0 (24.4%) and race 1 (22.2%) and the least prevalent races were race 23N and 123N having 13.3% each. Varied resistance response of different isolates was observed on differential lines having different resistant genes. Despite the fact that virulence was seen against all Ht resistance genes, NCLB control might be increased by combining qualitative Ht resistance genes with quantitative resistance.
RESUMEN
Maize is considered the third most important cereal crop in Asia after rice and wheat. Many diseases affect this crop due to the cultivation of various hybrids. This research aimed to characterize the causative agent of northern corn leaf blight disease in Bihar, India, caused by Exserohilum turcicum (Passerini) Leonard and Suggs. Leaf samples were collected from infected fields in five maize growing districts of Bihar in 2020-2022. A total of 45 fungal isolates from 135 samples were examined for cultural, morphological, and molecular characteristics and were identified as E. turcicum. The isolates were grouped into four groups based on colony color, i.e., olivaceous brown, blackish brown, whitish black, and grayish, and into two groups based on regular and irregular margins. The conidial shapes were observed to be elongated and spindle-shaped with protruding hilum, with conidial septa ranging from 2-12. Similarly, conidial length varied from 52.94 µm to 144.12 µm. ß-tubulin gene sequences analysis made it possible to verify the identities of fungal strains and the phylogenetic relationships of all isolates, which were clustered in the same clade. The ß-tubulin gene sequences of all the isolates showed a high level of similarity (100%) with reference isolates from GenBank accession numbers KU670342.1, KU670344.1, KU670343.1, KU670341.1, and KU670340.1. The findings of this study will serve as a baseline for future studies and will help to minimize yield losses.