Evaluating genetic variation in growth, needles, wood and oleoresin traits among various half-sib families of Pinus roxburghii

Aim: This study examines genetic variability in growth, needle, wood, and oleoresin traits of high-resin-yielding Pinus roxburghii (Sargent) families in the Shilli conservation reserve, Solan, Himachal Pradesh, India. The research investigates how these genetic traits correlate with resin yield and evaluates their heritability to enhance breeding and forestry programs. Methodology: Fieldwork was conducted in a Chir pine block plantation, measuring traits like DBH, needle thickness, wood specific gravity, and oleoresin yield. Genetic analysis involved heritability estimates, genetic gain calculations, and principal component analysis to assess trait correlations and diversity. Results: Needle thickness showed the highest heritability (97%), while moisture content had the most significant genetic advance (7.18%). Notably, resin yield displayed a positive correlation with diameter at breast height (0.737), moisture content (0.672) and wood specific gravity (0.616), indicating potential indirect selection targets in breeding. Interpretation: The study identifies influential genetic traits in enhancing resin yield and wood quality in Pinus roxburghii. These findings suggest practical applications in selective breeding, facilitating more effective forestry management and tree development initiatives to optimize resource production. Key words: Genetic gain, Heritability, Moisture content, Needle thickness, Pinus roxburghii