Studies on the relationship between yield and meteorological parameters of para rubber tree (Hevea brasiliensis)

Relationship between latex yield of natural rubber trees (Hevea brasiliensis) and climatic variables have been derived. Under humid tropical rainfed conditions, observed latex yields of rubber trees (clone RRII 105) are highly variable from 19.8 to 90.5 g per tree per tap. Maximum temperature experienced during 1 day, 7 days and 30 days prior to the tapping explains about 32%, 42% and 64%, respectively, of the day-to-day variability in latex yields. The multiple regression models to estimate latex yield on a tapping day, with different antecedent weather conditions are developed. The weekly weather conditions associated with optimum yields were maximum temperature of 30.4 degrees C, minimum temperature of 22.8 degrees C, 5.9 h sunshine and 72 mm of rainfall. Any deviation from these meteorological conditions up to 6 months duration may significantly influence latex production. In general, maximum temperature, sunshine duration, vapour pressure deficit and pan evaporation showed significant negative correlation with yield, irrespective of the time period considered. Whereas, significant positive association was observed between rainfall beyond a month period and the latex yield of rubber trees. (C) 1998 Published by Elsevier Science B.V.