Selection of Host Differentials for Elucidating Pathogenic Variation in Magnaporthe grisea Populations Adapted to Finger Millet (Eleusine coracana)

Abstract

Blast, caused by Pyricularia grisea (teleomorph: Magnaporthe grisea), is the most devastating disease of finger millet affecting production, utilization, and trade in Africa and Southeast Asia. An attempt was made to select a set of putative host differentials that can be used to determine virulence diversity in finger-millet-infecting populations of M. grisea. Thus, a differential set comprising eight germplasm accessions selected from finger millet core collection (IE 2911, IE 2957, IE 3392, IE 4497, IE 5091, IE 6240, IE 6337, and IE 7079) and a resistant (‘GPU 28’) and a susceptible (‘VR 708’) variety was developed. This differential set was used to study pathogenic variation in 25 isolates of M. grisea collected from Karnataka, Telangana, and Andhra Pradesh states in India. Based on the reaction (virulent = score ≥4 and avirulent = score ≤3 on a 1-to-9 scale) on host differentials, nine pathotypes were identified among 25 M. grisea isolates. Pathotype 9, represented by isolate Pg23 from Vizianagaram, was the most virulent because it could infect all of the host differentials except GPU 28. This study will be helpful in devising strategies for monitoring virulence change in M. grisea populations, and for identification of blast resistance in finger millet for use in disease resistance breeding programs.

Management of blast disease of finger millet (Eleusine coracana L. Gaertn) caused by Pyricularia grisea under field conditions in Dolakha, Nepal

“…After 25 days of transplanting, inoculum was sprayed using a Knapsack power sprayer in the evening at a concentration of 1×10 5 spores/ml with a drop of tween 20 for uniform dissemination on the foliage to create a uniform disease pressure. Sprinkler irrigation produced high humidity (>90% relative humidity) and leaf wetness to encourage the development of disease (Babu et al, 2015). After 10 days from the initial spray, a second inoculum was applied.…”

“…With a productivity of 0.98 t/ha, millet is grown on 31.65 million ha of land globally (FAOSTAT, 2021). Over 25 nations in Africa and Asia grow finger millet, which makes up roughly 12% of the world's millet acreage (Babu et al, 2015). It produces 314,225 Mt of millets across an area of 263,261 ha in Nepal with a productivity of 1.19 Mt/ha (MOALD, 2019).…”

Isolation, identification, and optimal cultivation of a marine bacterium antagonistic to Magnaporthe grisea

“…Global annual rice yield losses caused by M. grisea range from 11 to 30% (Tang et al, 2013;Li et al, 2014;Zhu et al, 2014;Shanmugapackiam et al, 2015), and infection can even cause crop failure. Spores are mainly responsible for infection (Choi et al, 2013;Motallebi et al, 2013;Li et al, 2014;Nehls and Dietz, 2014;Babu et al, 2015).…”

Effect of cultivar mixtures of Finger millet [Eleusine coracana L. Gaertn.] on blast [Pyricularia grisea (Cooke) Sacc.] disease development under field conditions

“…Despite its nutritional advantages over major cereals like rice and wheat, finger millet is a good source of minerals, proteins (7–14%) and gluten-free amino acids [ 1 ]. Finger millet grown in more than 25 nations of Africa and Asia continent, it makes around 12% of the world's millet area [ 2 ]. In field conditions, it faces significant challenges due to various diseases, particularly fungal infections like blast, brown spot, sheath blight, foot rot, green ear and smut diseases [ 3 ].…”