Latex Yield of Para Rubber (Hevea brasilliensis Muell. Arg) as a Function of Clonal Variation and Age at Tapping in Three Locations in the Niger Delta Region of Nigeria

The objective of this study was to assess the influence of clonal variability and tree-tapping age on latex yield in parts of the Niger Delta region of Nigeria. One exotic (GT 1) and three indigenous (NIG 800, NIG 803, NIG 805) clones of Hevea brasilliensis (Muell. Arg.), at three tree-tapping ages (‘young’, ‘prime’, ‘old’) were evaluated for latex yield in three estate plantations located in Calabar (latitude 4°58’N and 8°21’ E), Nko (latitude 5°5’ N; 8°11’ E), and Uyo (latitude 5°01’N and 7°56’E). A split – split plot in which location of plantings, type of clone, and age at which trees were tapped comprised the main-, sub-, and sub-sub- plots respectively, was used for the experiment, and treatments arranged in randomized complete block design replicated three times. Data were generated on trunk girth, percentage tree dryness, and latex yield. Girth size increased with age of tree irrespective of clone type and location of plantings. The average girth of ‘young’ GT 1, NIG 800, NIG 803, and NIG 805 was 48.65, 49.07, 50.63, and 52.13 cm, respectively indicating that NIG 805 and NIG 803 had a faster growth rate and attained the standard tappable girth of 50 cm earlier than NIG 803 and GT 1. Whilst ‘young’ NIG 805 and NIG 803 clones can be exploited, tapping NIG 800 and GT 1 clones at this stage of growth could have undesirable consequences on the tree’s physiology, productivity and longevity. Panel dryness exceeded 20% in all clones, with the highest incidence in GT 1 at 25.03%. This might have contributed to the relatively low yield of ‘old’ trees, in comparison to the ‘prime’ ones. Significant genotype × location interaction was found for latex yield, indicating that clonal and ecological conditions of each location made significant contributions to latex yield. Differences in clonal latex yield are attributable to variations in girth, panel dryness and ecological conditions.