Assessing Rice Phenology and Growth Using Agrometeorological Indices in Jagtial, Telangana, India
Srilaxmi Bottu *
Regional Agricultural Research Station, Polasa, Jagtial, PJTAU, Telangana, India.
Sreenivas Gade
Regional Agricultural Research Station, Polasa, Jagtial, PJTAU, Telangana, India.
Rajanikanth Eligeti
Regional Agricultural Research Station, Polasa, Jagtial, PJTAU, Telangana, India.
Srinivas Boddupalli
Regional Agricultural Research Station, Polasa, Jagtial, PJTAU, Telangana, India.
Sainath Nagula
Regional Agricultural Research Station, Polasa, Jagtial, PJTAU, Telangana, India.
*Author to whom correspondence should be addressed.
Abstract
Rice (Oryza sativa L.) is the principal staple crop of India, highly sensitive to temperature, rainfall distribution and radiation. To assess its climatic requirements, a long-term study (2014–2024) was conducted at RARS, Polasa, Telangana, using rice variety JGL 24423. Daily weather data were analyzed to compute agrometeorological indices - Growing Degree Days (GDD), Heliothermal Units (HTU) and Photothermal Units (PTU) from sowing to phenological stages. Results showed that a minimum of 776 GDD, 2624 HTU and 10045 PTU are required for panicle initiation, while physiological maturity needs 2076 GDD, 7759 HTU and 26054 PTU. Substantial variation across years reflected the influence of ENSO phases, rainfall variability and radiation availability. Excess rainfall during La Nina years lowered sunshine hours and HTU values, reducing yield, whereas balanced conditions in El Nino and normal years supported better productivity. The study underscores the importance of agrometeorological indices in predicting phenology, understanding crop-climate interactions and guiding weather-based management to sustain rice production in semi-arid tropics.
Keywords: Rice, agrometeorological indices, ENSO phases, phenology, climate variability