Profiling of macroscopic traits for grading bamboo for selection of plus culm

Abstract

This study evaluated the macroscopic culm characteristics of Bambusa vulgaris across three age classes— 2, 3, and 4 years with the goal of identifying key traits for plus-culm selection. Five culms per age class were harvested from naturally growing bamboo groves, and samples were collected from the base (10%), middle (50%), and top (90%) positions along each culm. Morphological parameters including culm length, number of nodes and internodes, internode length, internode diameter, and culm wall thickness were examined. The results revealed that culm height ranged from 16.43 m to 17.07 m, with the tallest culms recorded at age 4. Mean internode lengths were 40.47 cm, 40.73 cm, and 41.00 cm for ages 2, 3, and 4 respectively. Internode diameters were 7.23 cm, 7.95 cm, and 8.01 cm, while wall thicknesses were 0.99 cm, 1.09 cm, and 1.13 cm in ascending order of age. While numerical increases with age were observed in most
traits, statistical analysis showed no significant variation (p ≥ 0.05) in culm length, number of nodes, internodes, or wall thickness among the age classes. However, internode length, internode diameter, and wall thickness varied significantly (p ≤ 0.01) along the culm height. Regression analysis revealed strong relationships between age and key traits: internode length (R² = 0.99), internode diameter (R² = 0.88), wall thickness (R² = 0.98), and culm length (R² = 0.90). These findings highlight internode length, diameter, and wall thickness—especially in relation to culm position—as reliable indicators for plus-culm selection. This research supports the development of phenotypic selection protocols to enhance bamboo resource utilization in Nigeria.