Impact of Heat Units on the Phenology and Yield of Baby Corn (Zea mays L.) in Western Agro Climate Zone of Tamil Nadu

Field investigation was carried out during winter 2022 at Tamil Nadu Agricultural University, Coimbatore to study the phenological behaviour and yield of baby corn (Zea mays L.) as influenced by heat units. The split-plot design consisting three dates sowing viz., D1 – 21st January, D2 5th February D3 20th a main plot spacing 60x45 cm (S1), 60x30 (S2) 60x20 (S3) sub adopted replicated thrice. Growing Degree Days, Helio Thermal Unit Heat Use Efficiency were calculated for different stages plant emergence 50% flowering (P1), cob (P2), harvest (P3), (P4), (P5) (P6). results revealed that on Feb. had completed phenophases early, followed Feb Jan. GDD required attaining physiological maturity highest in (1194.6 ºC days)). Except morning relative humidity, wind speed solar radiation, all other weather parameters negative correlation with (R2=0.921). optimum temperature obtained (27.2 27.5 ºC) along short-day length (11.7 hours) resulting higher (9333.3 kg/ha) well HUE (5.75).