Geographical Variation in Morphological and Seed Traits of Quercus robur L. for Genetic Improvement

Abstract

Natural dye extracted from the cupules of Quercus robur L., combined with a mordant made from wood ash of Salix alba L. and Populus deltoides Bartram ex Marsh., produces various shades on fabrics such as pashmina, silk, and wool. Additionally, extracts from its acorns, when prepared with methanol, ethanol, acetone, acetonitrile, and chloroform, exhibit antimicrobial properties. The present study explores the geographical influence on Quercus robur L. for evaluating tree and seed traits for superior genetic propagation. The study was conducted during 2022-23. It aimed to evaluate the influence of location on key tree and seed morphological traits viz: tree height, diameter at breast height (DBH), crown height, crown width, seed aspect ratio (seed length: seed diameter), average seed weight, and average kernel weight with an emphasis on identifying superior plant genetics for propagation. Eighteen randomly selected trees were analyzed, with Rajbagh showing the most promising results. The tallest tree (T6) from Rajbagh reached 26 m, while the shortest (T1) measured 23 m. DBH ranged from 82.3 cm (T1) to 88.5 cm (T6), with T6 also exhibiting the largest crown height (2.5 m) and crown width (11.5 m). The highest seed aspect ratio (2.42) was recorded in T2, while T9 exhibited the lowest (1.94). The greatest average seed weight was observed in T6 (9.05 g), followed by T4 (8.85 g), whereas the lowest occurred in T1 (7.86 g). Kernel weight followed a similar trend, peaking in T6 (7.95 g) and reaching a minimum in T1 (5.63 g). Across all traits, the phenotypic coefficient of variation (PCV) exceeded the genotypic coefficient of variation (GCV), with kernel weight demonstrating the highest PCV (10.75) and GCV (9.61), followed by aspect ratio (PCV: 8.84; GCV: 7.78). The lowest PCV (6.11) and GCV (5.10) were also recorded for kernel weight. Genetic differences among tree populations or individuals can result in varied growth performance across different locations. Locations with less competition might see better growth rates. A comprehensive understanding of these variables is imperative for the strategic management and optimization of tree development across diverse geographical landscapes. The close correspondence between PCV and GCV values suggests strong genetic control with limited environmental influence. Overall, trees from Rajbagh consistently displayed superior phenotypic traits, indicating their potential for use in future genetic improvement programs.