Thermal influence on floral induction in mango (Mangifera indica L.): A study on two cultivars under Ultra High-Density Planting (UHDP)

Mango (Mangifera indica L.) is a globally significant tropical fruit, with India being the largest producer. Despite its economic importance, off-season mango production remains challenging due to the critical role of environmental factors on floral induction. This study investigates the thermal influence on floral initiation in two mango cultivars, Ratna and Bangalora, grown under the Ultra High-Density Planting (UHDP) system at Jain Irrigation Systems Limited Farms, Udumalpet, from 2022 to 2024. The study comprises the evaluation of flowering responses under both regular and off-season conditions. The experiment followed a randomized complete block design (RCBD) with three replications per cultivar, comprising 72 trees (36 per cultivar). Temperature thresholds for floral induction were determined using logistic regression models and the probability of flowering was analysed in relation to temperature integration periods. Results indicated cultivar-specific differences in temperature sensitivity. During the off-season, Bangalora exhibited 50 % flowering at a minimum temperature of 24.8 °C (95 % CI: 23.5 °C–26.0 °C) and a maximum of 35.5 °C (95 % CI: 34.0°C-37.0 °C). In contrast, Ratna required lower temperatures, with 50 % flowering occurring at a minimum of 21.3 °C (95 % CI: 20.5 °C-22.2 °C) and a maximum of 31.2 °C (95 % CI: 30.2°C-32.5 °C). During the regular season, optimal flowering temperatures were slightly lower, suggesting naturally favourable conditions. Findings confirm that temperature exposure and integration periods significantly affect floral induction, emphasizing the potential for controlled temperature management to optimize off-season production. These results provide critical insights into mango flowering physiology. It plays a crucial role in developing practical guidelines for farmers to regulate temperatures based on specific cultivars, ensuring year-round mango availability.