Screening for resistant sources against banded leaf and sheath blight on little millet

Introduction

Little millet (Panicum sumatrense Roth ex Roem. and Schult.) is a short-duration (75-110 days) C4 nutri-cereal cultivated in tropical and subtropical South Asia (Dey et al., 2024) [4] , rich in protein, fiber, B-complex vitamins (niacin, thiamine), and minerals (Fe, Zn, Cu, Mg, Se, P) (FAO, 2023). India is the leading producer (0.22-0.26 M/ha; 0.12-0.13 Mt/year), primarily growing it under rainfed conditions during kharif, with contingent potential in late kharif or rabi (Vetriventhan et al., 2023; Directorate of Economics and Statistics, 2023; ICAR-IIMR, 2024). Major millet-growing states (Madhya Pradesh, Chhattisgarh, Odisha, Tamil Nadu, Karnataka) report yields of 0.4-0.8 t/ha, but national productivity averages only 0.5-0.6 t/ha compared to a potential 2.5-3.0 t/ha due to biotic and abiotic stress (Directorate of Economics and Statistics, 2023; ICAR-IIMR, 2024). Fungal diseases cause 20% to >50% yield losses across growth stages: Rhizoctonia solani, Macrophomina phaseolina, and Fusarium spp. cause seedling damping-off (Patro et al., 2023); Pyricularia setariae / P. grisea, Helminthosporium nodulosum / Bipolaris spp., and Uromyces linearis cause vegetative foliage damage (Palanna et al., 2023;Tharana Poonacha et al., 2024); while Ustilago crameri / U. paradoxa and Sclerospora graminicola impair reproductive panicles (Dey et al., 2024) [4, 5, 8] . Banded Leaf and Sheath Blight (BLSB), caused by R. solani Kuhn, is particularly destructive in kharif under 25-30°C and 100% relative humidity (Jain & Kumar, 2023;Maddela et al., 2023;Patro et al., 2024;Prasanna et al., 2026). It forms greyish-white lesions with dark margins that coalesce into banded patterns, spreading upward from basal sheaths to induce necrosis, photosynthetic loss, and premature drying (Jain and Kumar, 2023;Poonacha et al., 2026), causing 30%-60% (or 37.4%-63.0%) yield loss and stover quality decline (Ramesh et al., 2023;Patro et al., 2024). Culturally, R. solani produces a white-to-brown mycelial mat with sclerotia (Kumar et al., 2025) [29, 5, 20, 16, 28, 4, 9, 12, 23, 9, 22, 24, 11] . Microscopically, it lacks asexual conidia, showing septate hyphae with 90° branching, origin constriction, and an adjacent septum (Sharma et al., 2024;Poonacha et al., 2025). To avoid pesticide hazards, host resistance is vital (Salam et al., 2023;Sowmika et al., 2025); thus, this study evaluated 30 little millet genotypes at ARS, Vizianagaram, to identify BLSB resistance [26, 21, 25, 27] .

Materials and methods

A field experiment was conducted against banded blight caused by R. solani during Kharif, 2023 at Agricultural Research Station, Vizianagaram. The experiment was laid out in Randomized Block Design (RBD), with 27 varieties which were received from AICRP (Small millets) along with two checks, replicated three times which was sown in two rows of 3 m length with a spacing of 30 x 10 cm. The recommended agronomic practices and other standard packages of practices were adopted at the time of crop growth period. Disease score was recorded on five randomly selected plants from each genotype/replication. The genotypes of little millet were screened under natural epiphytotic conditions, and no artificial inoculation was made. Infected plants were examined for disease development, and disease severity was assessed based on lesion length using a 1-9 scale (Table 1) at the grain maturity stage (Hariprasanna et al., 2022) [7] . >75% of plant area covered by lesion Percent Disease Index (PDI) was calculated by using the formula

The genotypes were categorized in to five disease reaction groups based on banded blight severity (Table 3).

Results and discussion

Twenty-eight little millet varieties, along with two checks, i.e., RLM-208 (Resistant) and RLM-223 (Susceptible), were screened for banded leaf and sheath blight (BLSB) reaction. Among the genotypes, none were found to be immune or resistant to R. solani, whereas nine entries were found to be moderately resistant, twelve entries were susceptible, and nine entries were found highly susceptible to BLSB disease (Table 3). 2). Previously, (Chouhan, 2014) [3] , who reported that among 27 entries screened, 12 were moderately resistant to BLSB. These genotypes would be of immense value to breeders involved in developing high-yielding and disease-resistant little millet genotypes [17, 13, 19, 18, 15, 25] . Thirty little millet genotypes were screened against banded leaf and sheath blight caused by Rhizoctonia solani along with one resistant and one susceptible variety as a check under natural conditions. No variety was found completely resistant to banded leaf and sheath blight disease during a year of experimentation, and the moderately resistant genotype (s) can be viewed as parental lines in resistance breeding programs.

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