Assessing dry rubber yield of 12 rubber clones using three tapping systems

Abstract

Rubber (Hevea brasiliensis Muell. Arg.) is a major high-value industrial crop in the Philippines, where latex productivity is strongly influenced by clonal characteristics, tapping systems, and prevailing climatic conditions. This study evaluated the dry rubber (DR) yield of twelve rubber clones subjected to three tapping systems (S2D2, S2D3, and S2D4) and examined their interaction with temperature, relative humidity, and rainfall. The experiment was conducted using a split-plot design arranged in a randomized complete block design with four replications, where tapping systems served as main plots and clones as subplots. Monthly dry rubber yields were recorded over one year (January–December 2023), and corresponding weather data were analyzed on a quarterly basis. Results revealed a highly significant interaction between tapping system and clone, while the main effect of tapping system alone was not significant. Climate had a strong modifying effect on yield expression. Frequent tapping (S2D2) was more effective during warm and relatively dry conditions in the first quarter, whereas longer rest intervals (S2D3 and S2D4) significantly improved yields during periods of high rainfall and relative humidity in the second and third quarters. Elite clones such as PB 260, USM 1, RRIM 2025, and RRIM 3001 consistently produced highDR yields (>1,500 kg ha⁻¹ yr⁻¹) when tapping frequency was synchronized with seasonal climatic patterns. Overall, S2D3 emerged as the most climate-resilient tapping system, providing stable yields across fluctuating temperature, humidity, and rainfall conditions. These findings demonstrate that rubber yield is governed by a strong interaction among clone, tapping system, and climate.