Phenological Responses of Selected Crotalaria Species to Climatic Variability in Tirupati, Andhra Pradesh, India

Abstract

Climate change is causing many plant species, especially in the tropics, to shift their phenological rhythms. The present study analyses the effect of major climatic factors: temperature, rainfall and humidity on the phenological events (vegetative growth, flowering, fruiting and seed dispersal) of four selected Crotalaria species: C. juncea, C. pallida, C. retusa and C. verrucosa. A field study was carried out in the Tirupati region of Andhra Pradesh, India, for a period of three years and five months (2022-2026). Biweekly phenological observations were connected to high-resolution climate data. Results showed species-specific phenological response, C. “ verrucosa had the longest length of flowering while C. juncea has a very restricted phenological cycle (180–210 days). High temperature and the arrival of the monsoon were shown to be the key triggers for the initiation of flowering. In all species, rising temperatures were associated with a large shift in flowering dates; C. pallida had the greatest sensitivity. The work provides important baseline data for anticipating the effects of future climate change on tropical legumes and adds to the creation of adaptive conservation measures.

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