Screening of Little Millet, Panicum sumatrense Germplasms for Resistance against Shoot Fly

Abstract

Little millet (Panicum sumatrense) is a vital climate-resilient small millet grown extensively in arid and semi-arid regions. However, seedling mortality caused by shoot fly, Atherigona pulla (Wiedemann) (Diptera: Muscidae), remains a primary biotic constraint, leading to substantial dead-heart formation and yield reductions. Field screening of 99 diverse little millet germplasms was conducted in an augmented block design at the Zonal Agricultural Research Station (ZARS), UAS, GKVK, Bengaluru, during two consecutive seasons (Kharif 2023 and Kharif 2024) under natural field infestation. Infestation levels were evaluated based on the percentage of dead-hearts recorded at 21 and 28 days after emergence (DAE) and were categorised using a standard 1–9 rating scale (Highly Resistant to Highly Susceptible). Variation in dead-heart damage was observed among the evaluated genotypes across both seasons. In Kharif 2023, the mean dead-heart percentage ranged from 5.00% to 53.33%, whereas in Kharif 2024, it ranged from 5.00% to 55.00%. Genotypes GPMP 609, GPMP 675, OLM 203 and GPMP 728 consistently displayed high levels of resistance, exhibiting the lowest mean dead-heart incidence (5.00% to 6.67%) with a score of 1. Other promising highly resistant entries included GPMP 642, GPMP 709, GPMP 669, GPMP 611, GPMP 671, GPMP 641 and GPMP 714. Conversely, germplasms GPMP 745, GPMP 700, GPMP 607 and the check DPLV 1 recorded severe infestations (53.33% to 55.00%) and were categorised as Highly Susceptible (score 9). The stable highly resistant genotypes identified in this investigation provide valuable donor germplasm for host-plant resistance breeding programmes aimed at developing pest-resilient, high-yielding cultivars of little millet without relying heavily on synthetic chemical interventions.