Intra- and Interclonal Variation in Anatomical Properties of Hevea Brasiliensis Muell. Arg.

The wood anatomical properties of two new rubberwood clones (RRIM 2020 [I] and RRIM 2025 [II]) at four planting densities (PDs) (500 [I], 1000 [II], 1500 [III], and 2000 [IV] trees/ha) were assessed. Fiber morphology, vessel features, and ray cell anatomy were measured. At PD I and PD II, fiber features were the highest quality. For vessel features, the highest quality was at PD I and PD IV. The moderate densities did not show substantial variation. Ray density from clone I demonstrated a direct relationship with PD because the highest value was at PD IV. Ray height showed a descending trend with increasing PD with significant differences in PD I and PD II vs PD III and PD IV in clone I. PD I showed the highest values with no significant difference compared with the others. PD in both clones did not significantly influence ray area. Some anatomical features of fiber, vessel, and ray were successfully quantified using a regression approach. The results predicted PD I as optimum for high wood quality production. Among the treatments, PD I of clone II resulted in the best quality anatomical properties