Assessment of growth attributes and fodder quality traits in Alnus nitida (Spach) Endl. natural populations

While Alnus nitida (Spach) Endl. is a vital multipurpose tree in the Western Himalayas, combined evaluations of phenotypic traits and fodder quality across wide elevation gradients are lacking. To address this gap, 15 natural populations in Himachal Pradesh (1000–2466 m above mean sea level) were evaluated during 2021–22 to establish a multi-trait baseline for tree improvement and elite genotype selection. The investigation was conducted in Chamba, Kullu and Shimla districts, covering an altitudinal range of 1000–2466 m above mean sea level. Fifteen sites (five each from district) were selected and five phenotypically superior trees from each site were evaluated for growth, leaf morphology and fodder quality parameters. Significant variation was observed among populations for morphological traits such as tree height, diameter at breast height, crown length, clear bole height and leaf characteristics, with populations from Bharmour, Salooni, Jubbal, Kotkhai and Rampur showing superior performance. Similarly, fodder quality traits including fresh and dry leaf weight, crude protein, crude fibre, ash content, ether extract and nitrogen-free extract exhibited considerable variability. Rampur recorded the highest leaf biomass (99.73 g) and crude fibre (25.94 %), while Bharmour recorded maximum crude protein (16.97 %) and ash content (5.23 %). Correlation, principal component and cluster analyses revealed substantial genetic diversity among genotypes. The findings highlight the potential for selecting superior populations for tree improvement, enhanced fodder value and sustainable agroforestry development in the Himalayan region.