Screening of Maize Doubled Haploid Lines for Resistance against Fall Armyworm and Pink Stem Borer under Artificial Infestation

This preliminary study evaluated 30 maize doubled-haploid (DH) lines for injury caused by fall armyworm (FAW), Spodoptera frugiperda, and pink stem borer (PSB), Sesamia inferens, under artificial infestation during the 2025–2026 rabi season. The trial was conducted in a net house using a randomised block design with two replications and resistant and susceptible checks. FAW leaf injury was scored at 14 and 21 days after infestation (DAI), ear damage was scored at harvest, and PSB injury was scored at 35 DAI. Among the DH lines, the descriptive mean FAW leaf-injury rating ranged from 3.00 to 5.60. DH 14 had the lowest mean score (3.00), placing it at the upper boundary of the operational resistant category, whereas DH 12, DH 15, DH 13, DH 18 and DH 17 had comparatively low scores within the moderately resistant category. DH 12, DH 14, DH 15, DH 18 and DH 23 also had the lowest ear-damage ratings. Mean foliar and ear injury were positively associated across all 32 entries (r = .877, n = 32, p < .001) and across the 30 DH lines alone (r = .836, p < .001). For PSB, DH-line scores ranged from 4.96 to 8.36. None of the DH lines fell within the least-susceptible class; DH 9, DH 21, DH 19, DH 7, DH 27 and DH 1 were moderately susceptible and had the lowest PSB injury among the DH material. The findings identify candidate lower-injury lines under the present test conditions, but the two-replication, single-season net-house design requires confirmation in replicated multi-season and field evaluations before stable resistance or breeding-donor status can be assigned.