Xylem sap flow and trunk growth of 5 hybrid rubber tree clones
This investigation studies growth rate and sap flux density of trees of five hybrid rubber tree clones. The clones were bred from the original RRIM600 (female) and RRII105 (male) clones. This study was conducted at the Nong Khai Rubber Research Center, in northeast Thailand, during the rainy season of June-August 2015. Three-year-old selections of five hybrid clones (code 7, 85, 91, 161, 172) were compared with the mother clone (RRIM600). The experimental design was randomized complete block design (RCBD) with six clones (treatments) and three periods (blocks). The xylem sap flow was measured by the transient thermal dissipation method, utilizing Granier's probe. Results showed that the trunk diameters of each of the six clones differed significantly (P<0.05); trees of clone code 91 had the smallest (3.88 cm), those of clone code 161 the larges trunk diameter (5.92 cm). Maximum and daily sap flux densities were not significantly different in trees of all clones. However, sap flux densities and trunk diameter were positively correlated (P<0.05), indicating a high transpiration and a positive effect on tree growth.
Isarangkool Na Ayutthaya, S., Rattanawong, R., Meetha, S., Songsri, P. and Kasemsap, P. (2018). Xylem sap flow and trunk growth of 5 hybrid rubber tree clones. Acta Hortic. 1197, 1-6
Hevea brasiliensis, sap flux density, transpiration, trunk girth, thermal dissipation method