Effect of Heat Stress on Morphological, Physiological and Yield-Related Traits in Forty Maize (Zea mays L.) Inbred Lines Under Natural Late-Sown Conditions

DOI: 10.22161/ijeab.113.10

Abstract:
Heat stress during reproductive stages is a major constraint to maize productivity, particularly under late-sown spring regimes. In present investigation, forty maize inbred lines were evaluated for morphological, physiological and yield-related responses under normal (7 February) and late (12 March) sowing at two locations (CCS HAU RRS, Uchani, Karnal and KVK, Damla, Yamunanagar) across Spring 2021 and 2022. A randomized complete block design with two replications generated eight environments. Traits recorded included days to 50% anthesis and silking, anthesis–silking interval (ASI), leaf senescence score (1–9), tassel blast (%), leaf firing (%), silk receptivity (%), kernels per row, hundred grain weight, shelling percentage, canopy temperature and plot grain yield. Pooled ANOVA indicated highly significant effects of genotype (G), environment (E) and G×E for all traits. Late sowing accelerated phenology, increased ASI and heat-injury symptoms (senescence, tassel blast, leaf firing), reduced silk receptivity and caused severe yield reductions (0.049–0.288 kg plot⁻¹ under late sowing vs. 0.584–0.862 kg plot⁻¹ under normal sowing). Genotypes HKI 1011, HKI MBR139, HKI 1344 and HKI 1664 maintained lower ASI, reduced senescence, higher silk receptivity and relatively stable yields under stress, qualifying them as potential donors for heat-tolerance breeding.

Keywords:
maize, heat stress, late sowing, anthesis–silking interval, grain yield, inbred lines, canopy temperature, G×E

Article Info:
Received: 27 Apr 2026; Received in revised form: 25 May 2026; Accepted: 31 May 2026; Available online: 08 Jun 2026

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