Variation in agro-morphological characteristics of red clover (Trifolium pratense L.) and its distribution under changing climate in the Kashmir Himalaya, India

The present study aimed to quantify variation in agro-morphological characters of Trifolium pratense across ecological gradients in Kashmir Himalaya and model and forecast its distribution under current and future climate using Maxent. The occurrence data was collected between 2016 and 2023 from 246 locations, including 22 sites representing 5 habitat types (apple orchards, agriculture fields, forest, roadside vegetation and moist habitat) for agro-morphological characterisation. Altitude, slope, soil moisture, soil organic carbon and canopy cover were measured at each site. Twenty-six morphologic characters (13 quantitative and 13 qualitative) were used for agro-morphological characterisation, analyzed by principal component analysis (PCA). Relationship between morphological characters and environmental variables was measured using redundancy analysis. For species distribution, eight non-collinear bioclimatic variables were selected. The results exhibited high intra-specific variability with apple orchards, forests and agriculture fields identified as important habitats. Eight quantitative characters exhibited significant differences (p < 0.05). The populations were grouped into four groups and first two PCA axes explained 43.32% variation. Model accuracy was satisfactory (AUC > 0.80). T. pratense distribution showed highest sensitivity to temperature, with mean diurnal temperature range, temperature seasonality, temperature of wettest quarter and elevation as hugely important. It attains maximum probability at elevations > 1600 m, and mean annual temperature > 15 °C. Projected distribution exhibited least changes in habitat extent and is predicted to remain almost steady for future climate scenarios. The study signifies T. pratense as highly valuable for developing forage germplasm while distribution scenarios could be utilized to explore areas of suitability for its cultivation and breeding.